• The NIDA Blog Team

    Pop quiz!  Don't worry, you won't be graded on this one.

    Question: If you look at the candy in the check-out aisle in your local store, an average chocolate bar is 1 serving, and an average bag of candy-covered chocolates (which has about 30 candies) is also 1 serving.

    What's the average serving of a marijuana edible chocolate bar or bag of a candy that has been infused with THC—the active ingredient in marijuana?

    Answer:  There is no average serving.

    Yes, it was a trick question. But that’s kind of what marijuana edibles are…tricky. At least for a person who doesn’t use marijuana regularly.

    Do the math

    For example, in Colorado, a single serving of an edible marijuana food product purchased for adult recreational use (as opposed to medicinal use) can’t have more than 10 milligrams of THC in it. BUT, there can be up to ten servings in the product or package. That means a single bag of marijuana candy, a marijuana chocolate bar, a marijuana brownie, or any other marijuana edible might contain as much as 100 milligrams of THC.

    Smoking marijuana delivers to the user about 5 mg of THC in one puff. So if you ate all ten gummies in a bag of marijuana candy—each one a single 10 mg “serving”—it would be like taking 20 hits of a marijuana cigarette at one time! Because it takes longer to feel the effects of the THC when you eat an edible compared to smoking marijuana—up to an hour or two, this happens a lot. People end up eating more than the recommended serving because they don’t “feel” it right away.

    But really, it also goes against how most people eat candy. When was the last time you just had one candy from a bag?

    Half a sip?

    Beverages containing cannabis can be even more confusing. For example, one product contains 7.5 servings in a bottle that is about the same size as a can of soda. Does that mean that you are supposed to take only one sip? A sip and a half? 

    Manufacturers may say it’s a great drink to share, but do you really want to share a bottle with 7.5 friends? That’s a little too much sharing, if you ask us. (And how do you find half a friend?)

    We all know that these THC-infused edibles and drinks are illegal for teens to use and buy. But many will find ways to try them. They may discover, though, that it isn’t worth long nights coping with overwhelming dizziness, hallucinations, and stomach sickness (common symptoms of overdose)—and, for a growing number of unlucky experimenters, trips to the emergency room.

    That’s what happened to New York Times reporter Trish Reske’s 21-year-old son, who had to be rushed to the hospital after eating all 6 servings of a marijuana chocolate bar. Not a great way to spend an evening.

    Tell us in the comments: What should manufacturers do to make marijuana edibles safer?

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    When we wrote about secondhand marijuana smoke in 2014, we still had many unanswered questions about its effects. Here’s what research since then has found:

    1. It’s hard to get “high” off of secondhand marijuana smoke. How much a room is ventilated could make the difference. A study found that if you’re in an unventilated room (the windows and doors are closed), and smoke is blown directly in your face for a while, it might make you feel a little sleepy and your thinking “fuzzy.” If the room is ventilated, this reaction probably won’t happen. But even if you feel normal, the smoke could get into your body and you could still fail a drug test.
    2. A study in rats indicates that secondhand marijuana smoke might harm your heart and blood vessels. In fact, when the rats inhaled the smoke for just one minute, their hearts and blood vessels didn’t function as well as normal for the next hour and a half! A study like this hasn’t been done in humans, but it’s troubling.

    Researchers still have many unanswered questions, but the available evidence suggests that while inhaling secondhand marijuana smoke isn’t as bad for your health as smoking marijuana, it isn’t harmless, either.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • People can smoke marijuana rolled up like cigarettes, put it into tea, or cook it into food or candy. Some people think that it is safer to inhale marijuana using electronic cigarettes, or vaporizers, because they are not inhaling smoke. This is called “vaping.” But studies show that vaping can be harmful because you still inhale chemicals.

  • Describes nationwide trends in drug abuse and addiction, focusing on past-month use for illicit drugs (including marijuana and prescription drugs), alcohol, and tobacco.

  • Image by NIDA

    The NIDA Blog Team

    According to the Monitoring the Future survey of more than 44,000 teens, many of today’s teens are thinking twice about using marijuana.

    In 2018, marijuana use declined among 8th graders and was the same for 10th and 12th graders compared to 2013, even though laws on marijuana use have changed in several states during those 5 years. (A reminder: Using marijuana is still illegal for teens in all 50 states.)

    Public health experts want to see more encouraging trends like these, because using marijuana brings risks, whether it’s smoked, vaped, or put in food. Let’s look at some of those risks:

    Marijuana affects the developing teen brain.

    Your brain continues to develop until you’re about 25 years old. Using marijuana regularly before then can have negative and long-lasting effects on a person’s cognitive development (in other words, on how well a person can think).

    Marijuana use is linked to problems in school.

    Marijuana dulls attention, memory, and learning skills—effects that can last for days and sometimes weeks, depending on how often it’s used. Students who use marijuana are more likely to quit high school or not get a college degree, compared with teens who don’t use marijuana.

    Marijuana can be addictive.

    For some people, repeated marijuana use can lead to a marijuana use disorder or addiction. Addiction means that a person has trouble controlling drug use even if it’s causing bad things to happen in school, with friends, or at home.

    People who begin using marijuana before age 18 are four to seven times more likely than adults to develop a problem with drugs. Marijuana use can lead to other problems, too.

    It’s more important than ever that teens get the message that marijuana use can affect their developing brains.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Sara Bellum

    When you’re driving down the highway at 60 miles per hour, you need a clear head. Driving while distracted by your phone or driving under the influence of alcohol both can lead to crashes and tragedy. Driving under the influence of marijuana is also dangerous, because of the way the drug affects the brain and body.

    Recent news reports have talked about how drugged driving crashes and deaths have surged since medical marijuana has become legal in more states. Now that marijuana is legal for those over age 21 in Colorado and Washington, the rates of drugged driving are likely to increase even more.

    This poses a problem for police and our criminal courts because there isn’t yet a test that can show a person’s marijuana levels the way a “breathalyzer” test can show how much alcohol is in a person’s system in just a few seconds. It also poses a problem for public safety. When people drive after using marijuana, they put themselves, their passengers, and anyone else on the road in danger.

    Evidence from driving studies indicates that marijuana can harm a driver’s ability to pay attention, awareness of time and speed, and ability to draw on information gained from past experiences. Impairment increases a lot when marijuana is combined with alcohol.

    Another problem is that marijuana stays in your system a lot longer than alcohol, which leaves a few hours after you stop drinking. A recent NIDA-funded study looked at long-term marijuana users very closely. The researchers found that even if a person hasn’t used marijuana in a month, it could still be detected in their blood—which may have an effect on a person’s ability to drive safely.

    The bottom line: Use of any mind-altering drug makes it highly unsafe to drive a car and is against the law—just like driving after drinking alcohol.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    Everybody knows how dangerous it is to drink and drive. (A refresher: Drunk driving kills over 10,000 people every year.) That’s why states established a blood alcohol concentration limit for drivers; if you’re pulled over and the alcohol in your breath is above that limit (.08 percent), you’re considered to be Driving Under the Influence (DUI) or Driving While Impaired (DWI).

    Now, with more states in the U.S. legalizing marijuana for medical and/or recreational use, there’s an increasing need to know the potential risks of “drugged driving.”

    To find out, NIDA joined forces with the Office of National Drug Control Policy (ONDCP), and the National Highway Traffic Safety Administration (NHTSA) for a three-year study on how inhaling marijuana with and without drinking alcohol affects the way people drive. In this two-part series we’ll show you just how they did it, and what they found out!

    Driving without actually driving

    Researchers can now measure driving performance safely, by using the University of Iowa's National Advanced Driving Simulator (NADS), which features state-of-the-art technology to mimic the driving experience in a very convincing way. Other driving simulators are more like video games, but NADS puts you in a real car, surrounded by a 360-degree virtual environment. It also measures tiny details, like where your eyes are looking when you face certain driving obstacles, such as pedestrians and oncoming traffic.

    NADS was developed [link removed] by NHTSA to enable research that aims to reduce driving accidents, injuries, and deaths by studying how people drive in certain situations, and the ways that certain driving conditions can contribute to safer driving. For instance, what are the safest designs for intersections, entrances and exits, highway signs, and so on?

    It’s a lot less expensive—and yes, a lot safer—to try out different options for roads, signs, etc., without having to actually build them. And a bonus for NIDA’s research: the simulator is just as effective at measuring how people drive under the influence of various drugs.

    Driving Simulator 101: better than Blu-Ray

    The main NADS set-up is a large dome, mounted on a rig that slides and tilts in all directions to give the “driver” sensations of motion. Engineers can install entire cars, and the cabs of trucks and buses, inside the dome. Every vehicle used in the NADS has the exact same interior instruments (dashboard, steering wheel, lighting, etc.) that its real make and model has.

    The motion system creates such a realistic driving experience that drivers feel steering, acceleration, and braking just as they would when driving a real vehicle. The latest visual and audio technology can create all kinds of driving settings and situations: from parking lots to city streets to gravel roads, from oncoming traffic to cars that swerve into your lane as they pass.

    Can you juggle and drive?

    NADS shows a lot more than whether a driver could get into an accident. When you’re driving, it may feel like all you’re doing is watching the road, but you’re actually paying attention to dozens of different things at the same time. It’s kind of like mental juggling.

    For instance, you’re monitoring whether you’re staying in the lane; using peripheral vision to note what’s in your immediate environment; observing what the car in front of you is doing, your distance from it, and what’s behind you in the rearview mirror; keeping tabs on your speed; and a lot more. Hopefully you’re able to keep doing all of that even when momentarily distracted, as when you glance at a GPS.

    NADS is outfitted with interior cameras and other devices that constantly gauge how well a driver handles all these tasks in different driving scenarios. It provides the most thorough data possible on someone’s minute-to-minute driving performance.

    So, back to the NIDA/ONDCP/NHTSA study using NADS: we’ll look at the first set of results in our next post: “Read This If You Know People Who Smoke Weed and Then Drive (Part 2).”

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    Do you know how long it took for tobacco smoking rates to significantly drop after researchers first linked smoking cigarettes to cancer? 40 years.

    In the 1920s, when the link to cancer was discovered, smoking was normal---in fact, ads for cigarettes even featured doctors saying it relieved stress! For years, people smoked in their homes and offices, in restaurants and stores, on planes and on trains. Wherever they went…they smoked.

    Changing habits

    In 1957, the nation’s top doctor—the U.S. Surgeon General—warned that cigarette smoking could cause lung cancer. Other government doctors began to speak out. Still, people continued to smoke.

    Over time, laws to protect the public’s health limiting where people could smoke, increases in the cost of cigarettes, and the growing body of evidence that smoking was directly linked to lung cancer helped lead turn the tide. Now, it’s surprising to find people smoking indoors; it’s the norm for people to have to go outside.

    Weed and the teen brain

    Today, it's marijuana that people, especially younger people, are beginning to view as "okay" or "less dangerous" or "normal." It reminds us of tobacco nearly 100 years ago—and not in a good way.

    A big difference, though, is for teens—we already know that for them, using marijuana comes with some serious risks. Evidence is strong that smoking marijuana on a regular basis can harm the developing teen brain. And long-term, regular use of marijuana starting in the teen years can impair brain development and lower IQ. In other words, the brain may not reach its full potential. 

    Perception vs. reality

    As more and more states legalize marijuana for adults, it will likely be easier to get (even for teens), and there’s a chance that the number of people who use it will increase. For teens, this could have real and lasting effects. The question is, how long will it take before perception catches up to reality? 

    Scholastic shares the facts surrounding the great marijuana debate with its recent article, "Marijuana: Breaking Down the Buzz."

    Tell us in comments, is marijuana the next tobacco? Do these facts change your perception?

    For additional facts about the brain and drugs, visit scholastic.com/headsup.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Marijuana changes how the brain works. It attaches to parts of your brain, and for most people, it tells your brain and body to feel calm and relaxed.

  • The principles listed below are the result of long-term research studies on the origins of drug abuse behaviors and the common elements of effective prevention programs. These principles were developed to help prevention practitioners use the results of prevention research to address drug use among children, adolescents, and young adults in communities across the country. Parents, educators, and community leaders can use these principles to help guide their thinking, planning, selection, and delivery of drug abuse prevention programs at the community level.

    Prevention programs are generally designed for use in a particular setting, such as at home, at school, or within the community, but can be adapted for use in several settings. In addition, programs are also designed with the intended audience in mind: for everyone in the population, for those at greater risk, and for those already involved with drugs or other problem behaviors. Some programs can be geared for more than one audience.

    NIDA's prevention research program focuses on risks for drug abuse and other problem behaviors that occur throughout a child's development, from pregnancy through young adulthood. Research funded by NIDA and other Federal research organizations—such as the National Institute of Mental Health and the Centers for Disease Control and Prevention—shows that early intervention can prevent many adolescent risk behaviors.

    Principle 1 - Prevention programs should enhance protective factors and reverse or reduce risk factors (Hawkins et al. 2002).

    • The risk of becoming a drug abuser involves the relationship among the number and type of risk factors (e.g., deviant attitudes and behaviors) and protective factors (e.g., parental support) (Wills et al. 1996).
    • The potential impact of specific risk and protective factors changes with age. For example, risk factors within the family have greater impact on a younger child, while association with drug-abusing peers may be a more significant risk factor for an adolescent (Gerstein and Green 1993; Dishion et al. 1999).
    • Early intervention with risk factors (e.g., aggressive behavior and poor self-control) often has a greater impact than later intervention by changing a child's life path (trajectory) away from problems and toward positive behaviors (Ialongo et al. 2001; Hawkins et al. 2008).
    • While risk and protective factors can affect people of all groups, these factors can have a different effect depending on a person's age, gender, ethnicity, culture, and environment (Beauvais et al. 1996; Moon et al. 1999).

    Principle 2 - Prevention programs should address all forms of drug abuse, alone or in combination, including the underage use of legal drugs (e.g., tobacco or alcohol); the use of illegal drugs (e.g., marijuana or heroin); and the inappropriate use of legally obtained substances (e.g., inhalants), prescription medications, or over-the-counter drugs (Johnston et al. 2002).

    Principle 3 - Prevention programs should address the type of drug abuse problem in the local community, target modifiable risk factors, and strengthen identified protective factors (Hawkins et al. 2002).

    Principle 4 - Prevention programs should be tailored to address risks specific to population or audience characteristics, such as age, gender, and ethnicity, to improve program effectiveness (Oetting et al. 1997; Olds et al. 1998; Fisher et al. 2007; Brody et al. 2008).

    Principle 5 - Family-based prevention programs should enhance family bonding and relationships and include parenting skills; practice in developing, discussing, and enforcing family policies on substance abuse; and training in drug education and information (Ashery et al. 1998).

    Family bonding is the bedrock of the relationship between parents and children. Bonding can be strengthened through skills training on parent supportiveness of children, parent-child communication, and parental involvement (Kosterman et al. 1997; Spoth et al. 2004).

    Parental monitoring and supervision are critical for drug abuse prevention. These skills can be enhanced with training on rule-setting; techniques for monitoring activities; praise for appropriate behavior; and moderate, consistent discipline that enforces defined family rules (Kosterman et al. 2001).

    Drug education and information for parents or caregivers reinforces what children are learning about the harmful effects of drugs and opens opportunities for family discussions about the abuse of legal and illegal substances (Bauman et al. 2001).

    Brief, family-focused interventions for the general population can positively change specific parenting behavior that can reduce later risks of drug abuse (Spoth et al. 2002b).

    Principle 6 - Prevention programs can be designed to intervene as early as infancy to address risk factors for drug abuse, such as aggressive behavior, poor social skills, and academic difficulties (Webster-Stratton 1998; Olds et al. 1998; Webster-Stratton et al. 2001; Fisher et al. 2007).

    Principle 7 - Prevention programs for elementary school children should target improving academic and social-emotional learning to address risk factors for drug abuse, such as early aggression, academic failure, and school dropout. Education should focus on the following skills (Conduct Problems Prevention Research Group 2002; Ialongo et al. 2001; Riggs et al. 2006; Kellam et al. 2008; Beets et al. 2009):

    • self-control
    • emotional awareness
    • communication
    • social problem-solving and
    • academic support, especially in reading

    Principle 8 - Prevention programs for middle or junior high and high school students should increase academic and social competence with the following skills (Botvin et al. 1995; Scheier et al. 1999; Eisen et al. 2003; Ellickson et al. 2003; Haggerty et al. 2007):

    • study habits and academic support
    • communication
    • peer relationships
    • self-efficacy and assertiveness
    • drug resistance skills
    • reinforcement of anti-drug attitudes and
    • strengthening of personal commitments against drug abuse

    Principle 9 - Prevention programs aimed at general populations at key transition points, such as the transition to middle school, can produce beneficial effects even among high-risk families and children. Such interventions do not single out risk populations and, therefore, reduce labeling and promote bonding to school and community (Botvin et al. 1995; Dishion et al. 2002; Institute of Medicine 2009).

    Principle 10 - Community prevention programs that combine two or more effective programs, such as family-based and school-based programs, can be more effective than a single program alone (Battistich et al. 1997; Spoth et al. 2002c; Stormshak et al. 2005).

    Principle 11 - Community prevention programs reaching populations in multiple settings—for example, schools, clubs, faith-based organizations, and the media—are most effective when they present consistent, community-wide messages in each setting (Chou et al. 1998; Hawkins et al. 2009).

    Principle 12 - When communities adapt programs to match their needs, community norms, or differing cultural requirements, they should retain core elements of the original research-based intervention (Spoth et al. 2002b; Hawkins et al. 2009), which include:

    • structure (how the program is organized and constructed)
    • content (the information, skills, and strategies of the program) and
    • delivery (how the program is adapted, implemented, and evaluated)

    Principle 13 - Prevention programs should be long-term with repeated interventions (i.e., booster programs) to reinforce the original prevention goals. Research shows that the benefits from middle school prevention programs diminish without follow-up programs in high school (Botvin et al. 1995; Scheier et al. 1999).

    Principle 14 - Prevention programs should include teacher training on good classroom management practices, such as rewarding appropriate student behavior. Such techniques help to foster students' positive behavior, achievement, academic motivation, and school bonding (Ialongo et al. 2001; Kellam et al. 2008).

    Principle 15 - Prevention programs are most effective when they employ interactive techniques, such as peer discussion groups and parent role-playing, that allow for active involvement in learning about drug abuse and reinforcing skills (Botvin et al. 1995).

    Principle 16 - Research-based prevention programs can be cost-effective. Similar to earlier research, recent research shows that for each dollar invested in prevention, a savings of up to $10 in treatment for alcohol or other substance abuse can be seen (Aos et al. 2001; Hawkins et al. 1999; Pentz 1998; Spoth et al. 2002a; Jones et al. 2008; Foster et al. 2007; Miller and Hendrie 2009).


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    37. Spoth, R.; Redmond, C.; Shin, C.; and Azevedo, K. Brief family intervention effects on adolescent substance initiation: School-level growth curve analyses 6 years following baseline. J Consult Clin Psychol 72(3):535-542, 2004.
    38. Spoth, R.; Guyull, M.; and Day, S. Universal family-focused interventions in alcohol-use disorder prevention: Cost effectiveness and cost benefit analyses of two interventions. J Stud Alcohol 63:219-228, 2002a.
    39. Spoth, R.L.; Redmond, C.; Trudeau, L.; and Shin, C. Longitudinal substance initiation outcomes for a universal preventive intervention combining family and school programs. Psychol Addict Behav 16(2):129-134, 2002b.
    40. Spoth, R.L.; Redmond, C.; Trudeau, L.; and C.S. Longitudinal substance initiation outcomes for a universal preventive intervention combining family and school programs. Psychol Addict Behav 16(2):129-134, 2002c.
    41. Stormshak, E.A.; Dishion, T.J.; Light, J.; and Yasui, M. Implementing family-centered interventions within the public middle school: linking service delivery to change in student problem behavior. J Abnorm Child Psychol 33(6):723-733, 2005.
    42. Webster-Stratton, C. Preventing conduct problems in Head Start children: Strengthening parenting competencies. J Consult Clin Psychol 66:715-730, 1998.
    43. Webster-Stratton, C.; Reid, J.; and Hammond, M. Preventing conduct problems, promoting social competence: A parent and teacher training partnership in Head Start. J Clin Child Psychol 30:282-302, 2001.
    44. Wills, T.; McNamara, G.; Vaccaro, D.; and Hirky, A. Escalated substance use: A longitudinal grouping analysis from early to middle adolescence. J Abnorm Psychol 105:166-180, 1996.


  • Sara Bellum

    Spice, also known as K2 or “synthetic (manmade) marijuana,” is not nice. News stories tell of some really bad effects, like one teen who was paralyzed after using the drug. And the deaths of 3 young people earlier this year in Iowa were also linked to Spice.

    With marijuana use continuing to rise and more states considering making it legal, it is important to get the word out that Spice is not fake marijuana. Calling Spice “fake pot” is just a marketing ploy to attract people to try it, making them believe that it is something familiar.

    In fact, some effects of Spice are much more intense than those of marijuana. Some users experience extreme anxiety, paranoia (believing someone is out to get you), and hallucinations (seeing and hearing things that aren’t real).

    People also report a fast heart rate, vomiting, agitation, and confusion. Spice can also raise blood pressure and cause reduced blood supply to the heart, and in a few cases it has been linked with heart attacks. People who use it a lot may experience withdrawal and addiction symptoms.

    Marijuana does not cause paralysis like in the Texas teen. Spice needs to be treated as a dangerous drug in its own right, not just a manmade form of marijuana.

    The good news is that Spice use is down, especially among high school seniors, who seem to be getting the message that it’s not a drug to mess with. That’s one particularly bright spot in NIDA’s 2013 Monitoring the Future statistics.

    Visit DrugFacts: Spice for more information.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    Our previous post looked at the National Advanced Driving Simulator that NIDA, the Office of National Drug Control Policy (ONDCP), and the National Highway Traffic Safety Administration (NHTSA) used for a three-year study on the effects of marijuana—with and without a low dose of alcohol—on people’s driving. What did the study discover?

    Conducting the study

    First, let’s look at how the study worked:

    (1) Researchers selected 18 participants between the ages of 21 and 55 who met specific criteria. The participants:

    • reported drinking alcohol and using marijuana no more than three times a week;
    • had been a licensed driver for no less than 2 years, and had a valid unrestricted license; and
    • had driven at least 1,300 miles in the previous year.

    The participants also:

    • had no past or current significant medical illness (i.e., a medical illness with a genuine, noticeable effect on daily life);
    • had no history of a significant negative experience with cannabis or alcohol intoxication, or with motion sickness;
    • were not pregnant or nursing; and
    • were not taking drugs that could cause harm if they were combined with cannabis or alcohol, or that are known to impact driving.

    (2) The participants were given specific amounts of marijuana, alcohol, both, or a placebo (something that wouldn’t get them intoxicated) before each simulated drive. Since the University of Iowa is a non-smoking campus, participants were given vaporized marijuana instead of the kind you smoke.

    (3) After spending the night at the University of Iowa Hospital to ensure that they were sober when the test began, the participants arrived at NADS, consumed the cannabis and/or alcohol or placebo, and then drove in the simulator for 45 minutes. They each did this six times, separated by at least a week between visits.

    One lane per customer

    As we mentioned in the previous post, the National Advanced Driving Simulator (NADS) measures many things about a driver’s behavior—eye movements, reaction times, steering—in lots of driving situations.

    The first results of the study focus on three aspects:

    • how much someone weaved within the lane;
    • the number of times the car left its lane; and
    • how fast the weaving was.

    Remember, the main research question was, What level of ∆9-tetrahydrocannabinol (THC) in the driver’s blood impaired their driving performance similarly to alcohol at the U.S. limit of 0.08 percent? THC is the main ingredient in marijuana that makes you high.

    The answer: A blood concentration of 13.1 ug/L (micrograms per liter of blood) of THC increased weaving of the car within the lane to the same degree as drivers with a .08 percent breath alcohol concentration. A single marijuana cigarette can impair your driving skills.

    Not quite “apples to apples”

    It’s important to note that this was the “blood marijuana concentration” recorded during driving, not at the time a person’s blood would be collected after an accident or police stop. Why is that important? Because the concentration of THC in the blood starts to decrease as soon as a person stops using marijuana. By the time a driver gets a blood test, their THC level will be below 13.1 ug/L, but that doesn’t mean they were okay when they were driving.

    Marijuana is often consumed in combination with alcohol. The study found that drivers who used both alcohol and marijuana weaved within lanes, even if their blood THC and alcohol concentrations were below the impairment concentrations of either one when used alone.

    This basically means that when alcohol and marijuana are used together, you need less of each to impair your driving skills. If this sounds complicated, it is. It’s just too risky to drink and drive, or smoke weed and drive.

    Did you miss Part 1? Read it here!

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    In concerts, at house parties, even in the hallway of apartment buildings, you may have come into contact and been exposed to secondhand marijuana smoke.

    In situations like these, people often worry how breathing someone else’s marijuana smoke affects them.  A couple of common questions and the answers may help you see through the fog of this smoky situation.

    Can you get high from inhaling secondhand marijuana smoke?

    Probably not. 

    You may have heard the phrase “contact high,” about someone breathing secondhand marijuana smoke and feeling a buzz. Studies have found that in extreme conditions, with lots of smoke blown directly into your face, you can feel the high and it can even show up in a urine test. But this is not a normal circumstance.

    Research shows that very little THC is exhaled back into the air when a smoker exhales. So little, in fact, that if you sat in a room while people exhaled the smoke of four marijuana cigarettes (sometimes called joints) in one hour, you wouldn’t get high.  You would have to be trapped in a room breathing the smoke of 16 burning joints before you started to show signs of being high. 

    Can you fail a drug test from inhaling secondhand marijuana smoke?

    Again, probably not.

    Since the amount of THC exhaled by marijuana smokers is so low, it would take a lot of secondhand exposure to fail a drug test. 

    In a 2010 study, researchers measured the effect of secondhand marijuana smoke on non-marijuana smokers.  The non-smokers were placed in a well-ventilated space with people casually smoking marijuana for 3 hours.  The researchers then took blood and urine samples from the nonsmokers. They found that THC was present, but the amount was well below the level to needed to fail a drug test.  Another study found similar results: Testing positive is rare and limited to the hours directly following exposure.

    What are the health effects of inhaling secondhand marijuana smoke?

    Researchers are still working to figure this out. We still don’t know how a person is affected if they live with a regular marijuana smoker. We also don’t know how higher amounts of THC in today’s marijuana cigarettes affects secondhand smoke.

    A recent study on rats suggests that secondhand marijuana smoke can do as much damage to your heart and blood vessels as secondhand tobacco smoke. But that study has not yet been done on humans.

    We also know marijuana smoke contains harmful and cancer-causing chemicals, the same way tobacco smoke does. But we still don’t know how it affects a person’s health in the long run. Lots more research still needs to be done. 

    Tell us in comments: what would you do if someone was smoking marijuana near you?

    Update: Read the blog post, “Two More Things We’ve Learned About Secondhand Marijuana Smoke.”

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • 2017 Teen MTF Video – 508 Visual Description

    00:00 Music plays

    00:03 On screen: Drug related words appear on screen with three human silhouettes on the left and three on the right. In the middle, a black diamond shape appears that reads “Teen Drug Use.” A blue banner appears across the bottom that reads “Monitoring the Future 2017.”

    00:05 On screen: Background transitions to blue.

    On screen text: Monitoring the Future is an annual survey of 8th, 10th, and 12th graders conducted by researchers at the Institute for Social Research at the University of Michigan, Ann Arbor, under a grant from the National Institute on Drug Abuse, part of the National Institutes of Health. 

    00:17 On screen: Background transitions to green.

    On screen text: Since 1975, the survey has measured how teens report their drug and alcohol use and related attitudes in 12th graders nationwide; 8th and 10th graders were added to the survey in 1991.

    00:28 On screen: Teal box drops down from the top

    On screen text: 43,703 students from 360 public and private schools participated in the 2017 survey. 

    00:32 – 00:40 On screen: Blue banner appears across the top of the screen that reads "Daily Marijuana Use Mostly Steady." An orange chart appears with a horizontal scale from 2007 to 2017 and a vertical scale of 1 percent to 7 percent. Three boxes appear left of center indicating 8th graders as green, 10th graders as light blue and 12th graders as dark teal. A green line graph crosses the chart, peaking at 1.5 percent in 2011 followed by a light blue line graph on top, peaking at 4.5 percent in 2013 and then a dark teal line graph on top of both peaking at 6.8 percent in 2011.  

    00:41 On screen: Teal box drops down from the top

    On screen text: 71.0 percent of high school seniors do not view regular marijuana smoking as being very harmful, but 64.7 percent say they disapprove of regular marijuana smoking. 

    00:49 On screen: A tan background is revealed and a blue banner appears across the top of the screen that reads "Binge Drinking Rates Steady After Decades of Decline." A line graph with a horizontal scale appears with dates from 1992 to 2017. A vertical scale appears with percentages from 5 percent up to 35 percent. A green line indicating 8th graders draws across the graph and a beer bottle appears with a tag that reads "1996, 13.3 percent” and ends with a tag at 2017 that reads “8th graders, 3.7 percent.” A light blue line indicating 10th graders draws across the graph and a beer bottle appears with a tag that reads "2000, 24.1 percent" and ends with a tag at 2017 that reads “10th graders, 9.8 percent.” Finally, a dark teal line indicating 12th graders draws across the graph and a beer bottle appears with a tag that reads "1998, 31.5” percent and ends with a tag at 2017 that reads “12th graders 16.6 percent." A disclaimer at the bottom reads "*Binge drinking is defined as having 5 or more drinks in a row in the last 2 weeks." 

    01:01 On screen: Teal box drops down from the top. 

    On screen text: Binge drinking appears to have leveled off this year, but is still significantly lower than peak years. 

    01:08 On screen: A light green background is revealed and a blue banner appears across the top of the screen that reads "Past-year e-vaporizer use and what teens are inhaling." A black vertical line draws down the screen. Left of the line three boxes appear, on the top, a green box that reads "8th graders, 13.3 percent.” Right of the line, a green e-vaporizer extends horizontally to the right to show the amount. Below the green box, left of the line, a light blue box appears that reads "10th graders, 23.9 percent.” Right of the line, a light blue e-vaporizer extends horizontally to the right to show the amount. Below the light blue box, left of the line, a dark teal box appears that reads "12th graders, 27.8 percent.” Right of the line, a dark blue e-vaporizer extends horizontally to the right to show the amount. The dark blue, 12th graders e-vaporizer is the longest, indicating 12th graders use e-vaporizers the most. 

    01:16 On screen: The e-vaporizer graph disappears and the words, "When asked what they thought was in the e-vaporizer mist students inhaled the last time they smoked, these were their responses:” appears

    01:23 On screen: The on-screen text shrinks and moves to the top of the screen. An orange chart appears with three boxes left of the chart – a green 8th graders box, light blue 10th graders box, and dark teal 12th graders box. The vertical scale spans from 10 percent to 80 percent and the horizontal scale includes the categories, “Nicotine,” “Marijuana or Hash Oil,” “Just Flavoring,” “Other,” and “Don't Know.” Green, light blue and dark teal bars rise vertically above each category. The bars indicate that 50 percent – 75 percent of all three age groups think the e-vaporizer mist is "Just Flavoring" and 10 percent – 31 percent think the e-vaporizer mist is "Nicotine." 

    01:37 On screen: Teal box drops down from the top. 

    On screen text: Nearly 1 in 3 students in 12th grade report past-year use of e-vaporizers, raising concerns about the impact on their long-term health. 

    01:45 On screen: A light teal background is revealed and a blue banner appears across the top of the screen that reads "Teens more likely to use marijuana than cigarettes." Underneath the banner reads "Daily use among 12th graders." A graph appears with a horizontal scale of dates ranging from 1992 to 2017 and a vertical scale from 0 percent to 25 percent. A marijuana leaf with a green tag that reads "1992, 1.9 percent" appears at the base of the vertical axis of the graph and a green line draws across the chart ending at the far right above 2017 with a green tag that reads "Marijuana, 5.9 percent." The graph shows the increase in the likelihood that 12th graders will use Marijuana. At the same time, a white line draws across the graph starting at 17.2 percent in 1992, when it reaches its peak a pack of cigarettes appears with a white tag that reads “1997, 24.6 percent” and then dives down across the remainder of the chart where a second white tag appears and reads “Cigarettes, 4.2 percent” in 2017. This graph shows that in 2017, 12th graders are more likely to use marijuana than cigarettes. 

    01:57 On screen: A light gray background appears and a blue banner unveils across the top of the screen that reads "Past-year misuse of prescription/over-the-counter vs. illicit drugs." Below that, an orange prescription pill bottle appears on the right.

    On screen text: Past-year misuse of Vicodinâ among 12th graders has dropped dramatically in the past 15 years.

    02:08 On screen: The pill bottle shrinks and moves to the top of the screen below the blue banner. A chart appears right of center with the title " Vicodinâ " at the top. The chart's vertical scale ranges from 1 percent to 11 percent and the horizontal scale has dates from left to right – 2002, 2007, 2012 and 2017. Small white pills fall from the bottle, landing on specific data points. One pill lands on 2002 and a teal tag appears that reads “9.6 percent,” the next lands on 2007 at 9.6 percent, the next lands on 2012 at 7.5 percent and the last pill lands on 2017 and a teal tag appears that reads “2.0 percent.” The graph shows a dramatic decrease in the misuse of Vicodinâ over the 15-year span. 

    02:13 On screen: A teal box drops down from the top. 

    On screen text: Misuse of all prescription opioids among 12th graders has also dropped dramatically, despite high opioid overdose rates among adults. 

    02:20 On screen: Teal box pulls down to reveal the blue banner that still reads "Past-year misuse of prescription/over-the-counter vs. illicit drugs.” Underneath the blue banner the title, “Prescription/OTC” appears. An orange box appears below the title. Percentages appear down the left side of the chart while blue bars extend horizontally from left to right in the orange box to visually represent the amounts of prescription, over-the-counter and illicit drugs that were misused in the past year. From top to bottom the chart reads, “5.5 percent, Adderallâ,” “4.7 percent, Tranquilizers,” “4.2 percent, Opioids other than Heroin,” “3.2 percent, Cough/Cold Medicine,” “2.9 percent, Sedatives,” and “1.3 percent, Ritalinâ.” 

    02:32 On screen: The chart changes. The title reads "Illicit Drugs, past-year use among 12th graders." The chart animates similar to the previous chart, percentages are listed down the left of the chart, while blue bars extend from left to right. From top to bottom the chart reads, “37.1 percent, Marijuana/Hashish,” “3.7 percent, Synthetic Cannabinoids*,” “3.3 percent, LSD,” “2.7 percent, Cocaine,” “2.6 percent, MDMA (Ecstasy/Molly),” “1.5 percent, Inhalants,” and “0.4 percent, Heroin.” An asterisk below the chart notes that Synthetic Cannabinoids are called "synthetic marijuana in survey." 

    02:44 On screen: A teal box drops down from the top. 

    On screen text: Students report lowest rates for some drugs since start of the survey.

    02:48 On screen: A green screen drops down from the top. 

    On screen text: Across all grades, past-year use of heroin, methamphetamine, cigarettes, and synthetic cannabinoids* are at their lowest by many measures. An asterisk at the bottom of the screen notes that Synthetic Cannabinoids are called "synthetic marijuana in survey."

    02:55 On screen: Green screen changes to dark gray screen with Department of Health and Human Services and NIH National Institute on Drug Abuse logos. 

    On screen text: For more information, please visit Drugabuse.gov

    03:07 Music ends

  • Short-Term Effects

    1. Feel less coordinated and react more slowly
    2. Altered sense of time
    3. Feeling relaxed
    4. Anxiety, fear, distrust, or panic (when taken in high doses)
    5. Feeling really hungry
    6. Fast heart rate

    Long-Term Effects

    1. Problems with memory and learning skills
    2. Problems with breathing
    3. Cough or lung sickness
    4. Severe nausea and vomiting
  • The NIDA Blog Team

    Maybe you’ve heard that marijuana is similar (or identical) to something called hemp. If you’ve seen hemp necklaces or hemp shampoo on store shelves, or heard that Thomas Jefferson, the third president of the United States, grew hemp, you may have wondered: Wait a minute, you mean I can wash my hair with liquid marijuana? Our third president grew weed?

    The answer is more complicated than you might think.

    Here are some facts on hemp and its relation to marijuana:

    What exactly is hemp?

    “Hemp” is another name for the Cannabis sativa plant and its products. This same species of plant is also called marijuana.

    Is hemp the same thing as marijuana?

    Yes and no. Hemp and marijuana are both names for the Cannabis sativa plant, but people usually use these terms to talk about two different varieties of the plant.

    Varieties grown to make hemp rope and other products you see on the shelves (including the varieties Jefferson and others grew during the 1700s) have a whole lot less of the chemical that makes marijuana users feel high. Those varieties are sometimes called “industrial hemp.”

    Varieties grown for use as a drug have been specifically bred to have lots of THC, or delta-9-tetrahydrocannabinol, which is the chemical that makes users feel high.

    What is industrial hemp used for?

    The stalks of industrial hemp—remember, that’s the kind with low levels of THC—can be made into rope, paper, wax, and cloth for furniture or clothes. Sterilized hemp seeds can be made into oil for shampoo, soap, or body lotion. The seeds can also be mixed in with food for animals.

    Is hemp illegal?

    Cannabis sativa is usually illegal under U.S. federal law, but there are exceptions to that rule for products made from hemp that do not contain THC, like paper and shampoo. The U.S. imports some industrial hemp products, and some states also allow farmers to grow industrial hemp.

    What’s the short answer?

    Hemp rope and joints of marijuana come from different varieties of the same plant. The hemp that’s made into rope or jewelry won’t make a person high.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Image by State of Colorado

    The NIDA Blog Team

    People who make marijuana edibles often advertise them as if they’re just like candy. They sometimes design the edibles to look like candy, too. Even the products’ names (like “jelly bomb”) and fun-sounding flavors are intended to make them sound sweet and harmless.

    Whatever the people selling them tell you, though, marijuana edibles are not candy. Not even close.

    Easy to overdose

    Many people don’t know that it takes longer to feel the effects of marijuana when it’s put in food.

    People who are used to the quick high they get from smoking marijuana (which allows the drug to get into their bloodstream quickly via the lungs) may be disappointed with edibles. They have to wait for the drug to be absorbed through their stomach, which can take more than an hour. In the meantime, they may get impatient and eat too much of the edibles.

    Then too much THC gets into their body in a short time. An overdose like that can lead to overwhelming dizziness, hallucinations, and stomach sickness—sometimes serious enough to send people to the ER

    Edibles are especially dangerous for young children, who may see them at home and eat them. Hospitals in states where marijuana has been legalized have warned adults not to leave marijuana edibles around where they could tempt children who think they’re regular candy.

    Laws on edibles

    Colorado, one of the first states to legalize marijuana for use by adults, changed its laws on edibles in 2016:

    • The words “candy” or “candies” can’t appear on packages of marijuana or edibles.
    • Edibles can’t be shaped like people, animals, fruits, or cartoons.
    • Manufacturers must put a THC symbol (see image) not only on each package of edibles, but also on each individual edible sold in Colorado.

    Using marijuana in any form is illegal for people under age 21. Adults who use it should learn about the possible health effects of edibles, and help educate young people about the potential health risks.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Yes, you can. Over time, marijuana can change the way your brain works. If you stop using marijuana, your body can get confused and you can start to feel sick. This makes it hard to stop using marijuana. This is called addiction.

    Anyone can become addicted to marijuana. It doesn’t matter how smart you are or where you live. There is no way to predict who is likely to become addicted.


    Did you know that using marijuana as a teen can change how your brain grows?

    That’s because your brain is still growing and changing until you get into your 20s.

  • "Spice" refers to a wide variety of herbal mixtures that produce experiences similar to marijuana (cannabis) and that are marketed as "safe," legal alternatives to that drug. Sold under many names, including K2, fake weed, Yucatan Fire, Skunk, Moon Rocks, and others — and labeled "not for human consumption" — these products contain dried, shredded plant material and chemical additives that are responsible for their psychoactive (mind-altering) effects.

    False Advertising

    Labels on Spice products often claim that they contain "natural" psycho-active material taken from a variety of plants. Spice products do contain dried plant material, but chemical analyses show that their active ingredients are synthetic (or designer) cannabinoid compounds.

    For several years, Spice mixtures have been easy to purchase in head shops and gas stations and via the Internet. Because the chemicals used in Spice have a high potential for abuse and no medical benefit, the Drug Enforcement Administration (DEA) has designated the five active chemicals most frequently found in Spice as Schedule I controlled substances, making it illegal to sell, buy, or possess them. Manufacturers of Spice products attempt to evade these legal restrictions by substituting different chemicals in their mixtures, while the DEA continues to monitor the situation and evaluate the need for updating the list of banned cannabinoids.

    Spice products are popular among young people; of the illicit drugs most used by high-school seniors, they are second only to marijuana. (They are more popular among boys than girls — in 2012, nearly twice as many male 12th graders reported past-year use of synthetic marijuana as females in the same age group.) Easy access and the misperception that Spice products are “natural” and therefore harmless have likely contributed to their popularity. Another selling point is that the chemicals used in Spice are not easily detected in standard drug tests.

    Past year use of illicit drugs by high school seniors 2012, Marijuana/Hashish 36.4%, Synthetic Marijuana 11.3%, Hallucinogens 4.8%, Salvia 4.4%, MDMA 3.8%, Cocaine 2.7%

    How Is Spice Abused?

    Some Spice products are sold as “incense,” but they more closely resemble potpourri. Like marijuana, Spice is abused mainly by smoking. Sometimes Spice is mixed with marijuana or is prepared as an herbal infusion for drinking.

    Image of K2, a popular brand of “Spice” mixture.
    K2, a popular brand of “Spice” mixture. Image courtesy of Coolidge Youth Coalition

    How Does Spice Affect the Brain?

    Spice users report experiences similar to those produced by marijuana—elevated mood, relaxation, and altered perception—and in some cases the effects are even stronger than those of marijuana. Some users report psychotic effects like extreme anxiety, paranoia, and hallucinations.

    So far, there have been no scientific studies of Spice’s effects on the human brain, but we do know that the cannabinoid compounds found in Spice products act on the same cell receptors as THC, the primary psychoactive component of marijuana. Some of the compounds found in Spice, however, bind more strongly to those receptors, which could lead to a much more powerful and unpredictable effect. Because the chemical composition of many products sold as Spice is unknown, it is likely that some varieties also contain substances that could cause dramatically different effects than the user might expect.

    What Are the Other Health Effects of Spice?

    Spice abusers who have been taken to Poison Control Centers report symptoms that include rapid heart rate, vomiting, agitation, confusion, and hallucinations. Spice can also raise blood pressure and cause reduced blood supply to the heart (myocardial ischemia), and in a few cases it has been associated with heart attacks. Regular users may experience withdrawal and addiction symptoms.

    We still do not know all the ways Spice may affect human health or how toxic it may be, but one public health concern is that there may be harmful heavy metal residues in Spice mixtures. Without further analyses, it is difficult to determine whether this concern is justified.

    Learn More

    For more information on Spice, see

  • The NIDA Blog Team

    This is the first post of a 3-part series on the science of medical marijuana.  Check out Part 2: Making Medicine From Marijuana, and Part 3: Medicines or Poisons?—Why Cannabinoids Can Both Help and Hurt You.

    Before modern medical science, most medicines were raw herbs or herbal concoctions of one sort or another. They sometimes helped patients, but those benefits weren’t very powerful by today’s standards, and they often had a lot of unpredictable or even dangerous side effects.

    That’s because all plants contain hundreds or thousands of different chemicals. If you eat or smoke the leaves of any plant, you are putting all those chemicals in your body, and the results can be unpredictable.

    Marijuana is no different.

    Still, there is growing public support for “medical marijuana,” based on anecdotal evidence (that is, from individual people’s personal experience) that the drug might be useful in treating various diseases, including PTSD (post-traumatic stress disorder), pain, and epilepsy.

    Voters in 23 states have now passed laws allowing marijuana to be dispensed to patients, as long as they receive permission from a doctor.

    Why doesn’t the Food and Drug Administration (FDA) approve “medical marijuana”?

    Turns out, there’s very little scientific evidence that smoking or eating marijuana is effective and safe for treating any medical issues. Scientific evidence would have to come from carefully controlled research studies.

    Since there’s no science to back it up, the FDA has not approved smoked or vaporized marijuana for the treatment of any medical condition.

    The FDA only approves medicines when large studies examining lots of patients (called clinical trials) show that the medicines work safely. Without these studies, the FDA can’t promise people that the medications will help them and not harm them. 

    So why haven’t there been clinical trials on marijuana? 

    Because marijuana is a raw herb. There are over 500 different chemicals in marijuana, in combinations that vary widely between different strains and even from plant to plant. This causes serious problems trying to use the whole marijuana leaf, or crude extracts like hash oil, as medicine:

    1. It’s hard to deliver precise, accurate doses of the right chemicals;
    2. It can harm the lungs if users smoke it; and
    3. It causes additional effects—like the “high”—that may interfere with the quality of life of patients taking the drug for serious medical conditions.

    Plus, when used by teens or children, it could even harm their brains as they develop.

    Today, there are almost no approved medicines that are whole herbs. Although it’s not impossible, it would be very unusual if marijuana became an exception.

    How can we discover and use marijuana’s medical benefits without the harms?

    In Part 2, you'll learn how scientists are busy trying to create actual medicines from the chemical ingredients in marijuana.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    Smoking marijuana extracts, sometimes called “dabbing,” has become more popular in recent years, and it has some doctors concerned.

    Marijuana extracts—concentrated oils from the marijuana plant (sometimes called “hash oil”)—are a lot stronger than dried marijuana. The higher THC levels are what draw some people to try marijuana extracts. On average, regular marijuana has a THC content of 12–13 percent. (Remember, THC is the chemical in pot that makes users feel high.) But the average marijuana extract has a THC content of more than 50 percent, and some extracts are as much as 80 percent THC!

    Side effects may include explosions

    Because the THC and other chemicals are more concentrated in marijuana extracts than in regular marijuana, the side effects of dabbing—like poor judgment and coordination—are likely to be more powerful than those from smoking weed. Since dabbing is so new, there are not many studies on this yet, unfortunately.

    Marijuana extracts can also be very dangerous to make. One method for extracting the concentrated drug from regular marijuana involves forcing butane (a flammable chemical often found in lighter fluid) through a marijuana-packed pipe. Sometimes it works; sometimes it blows the house up, landing the maker in a burn unit (or worse). 

    Dab at your own risk

    Some scientists have said there should be more public education about the risks of dabbing. In 2014, one study found that, although using dabs didn’t cause more accidents than smoking marijuana buds, the extracts did cause people to build up a higher tolerance to THC and to have more symptoms of withdrawal.

    Also, in a 2015 study, over 80 percent of marijuana extracts studied were contaminated with pesticides or poisonous solvents left over from the extraction process.

    Marijuana in general is bad for teens’ developing brains. A new way to smoke marijuana doesn’t make it any safer.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team
    Studies show that marijuana interferes with attention, motivation, memory, and learning. Students who use marijuana regularly tend to get lower grades and are more likely to drop out of high school than those who don’t use. Those who use it regularly may be functioning at a reduced intellectual level most or all of the time.
    Check out NIDA's new infographic that explains what that means in the classroom, and how that can affect your life.  
    Marijuana Use & Educational Outcomes Infographic
    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • ©Shutterstock/Iryna_Tiumentseva

    The NIDA Blog Team

    Using marijuana comes with risks: It can cause some health problems and increase your chances for an injury or accidents. When a pregnant woman uses marijuana, the risks increase, because her unborn baby’s birthweight or brain development could also be affected.

    A rising trend

    Unfortunately, marijuana use during pregnancy is on the rise. Based on a 2016 government survey, 4.9 percent of pregnant women aged 12–44 had used marijuana in the previous month, compared to 3 percent in 2002.1

    What’s even more concerning is the risky behavior related to both teen pregnancy and early marijuana use. According to a recent study, 14 percent of pregnant girls aged 12–17 in the United States had used marijuana in the past month. That’s more than twice the percentage of their nonpregnant peers who used it.

    A risky choice

    What could be causing this troubling trend? It’s possible that some women didn’t know they were pregnant when they used marijuana, and some women don’t know about the dangers of using marijuana during pregnancy. (For a reminder of those dangers, check out this blog post.)

    A recent study found that 70 percent of medical marijuana shops in Colorado recommend marijuana for pregnant women in their first trimester to help with morning sickness—despite warnings from doctors.2 Morning sickness is the feeling of upset stomach and nausea that often comes with pregnancy (sometimes it lasts all day).  

    But the possibility of reducing morning sickness just isn’t worth the risks that come from using marijuana during pregnancy. It’s unsafe for baby, and quite possibly for mom, too.

    Sources Cited:
    1. Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration. Special data run based on the 2002-2016 National Surveys on Drug Use and Health data.
    2. Dickson B. et al, Recommendations From Cannabis Dispensaries About First Trimester Cannabis Use; Obstetrics and Gynecology Vol. 131, No. 6, June 2018, pp.1031-1038.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • For teachers: Background information and classroom activities for use with the Marijuana Student Booklet.

    Marijuana is the dried leaves and flowers of Cannabis Sativa. Delta-9-tetrahydrocannabinol (THC) is the main active ingredient in marijuana that causes people who use it to experience a calm euphoria. Marijuana changes brain messages that affect sensory perception and coordination. This can cause users to see, hear, and feel stimuli differently and to exhibit slower reflexes.

  • All materials appearing in the ​Research Reports series are in the public domain and may be reproduced without permission from NIDA. Citation of the source is appreciated.

  • The NIDA Blog Team

    This is the second post of a 3-part series on the science of medical marijuana.  Check out Part 1: What’s Wrong With “Medical Marijuana”? and Part 3: Medicines or Poisons?—Why Cannabinoids Can Both Help and Hurt You.

    What people usually mean by “medical marijuana” is use of an unprocessed (raw) plant to treat illness—or herbal medicine, in other words. Unprocessed means the leaves, stems, or seeds are just taken off the plant and used.

    Before the 20th century, that’s mostly what medicine was.

    But science has made a lot of progress in the last several decades, and generally it hasn’t looked back. It’s because we now have ways of picking out the specific chemicals that are useful from plants and putting just those parts in a pill, without all the unwanted chemicals that might cause side effects or even be toxic.

    This is what a lot of scientists are busy doing right now with marijuana—trying to figure out which chemicals in the plant really are useful in treating health problems and then finding ways to deliver them safely and effectively to patients to treat their conditions.

    Turning Marijuana into Medicine

    At the last count, scientists have found over 500 separate chemicals in the marijuana plant. The main chemical that gives users the “high” is tetrahydrocannabinol, or THC, but there are over 100 other chemicals in marijuana that have a similar molecular structure to THC. This family of chemical compounds is called cannabinoids.

    So far, there are two FDA-approved medications containing THC for treating nausea and appetite problems caused by cancer chemotherapy and AIDS. Other drugs with THC in them have been approved already in other countries for treating symptoms of multiple sclerosis (MS) and are now being carefully tested before being approved in the United States.

    Another marijuana chemical is cannabidiol, or CBD. News reports have highlighted some families who are living in states where medical marijuana is legal so their children with bad forms of epilepsy can get special high-CBD marijuana extracts to help control seizures.

    These extracts probably still contain other, possibly harmful ingredients. But a medicine only containing CBD is now being tested in the United States. If the science finds that CBD really is a good treatment for seizures, eventually patients may be able to take that or another safe, CBD-based medication. This could help people get the safe treatment they need.

    Cannabinoids and Other Diseases

    Lots of different cannabinoid chemicals are being studied to see whether they have beneficial effects on conditions ranging from addictions and other mental health problems to pain and other serious conditions. Most are still a long way from being studied in humans and going on to become medications.

    In Part 3, we’ll look at why chemicals in the marijuana plant could be so helpful even though they may also be harmful. It turns out, marijuana’s not unique in being two-faced!

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    The Super Bowl is only a few days away. From the game itself to the halftime show to the commercials (of course!), the event has something for everyone. Most people who tune in, however, won’t realize that behind the scenes, a different competition is going on: the National Football League (NFL) vs. drug use.

    Some NFL players may abuse prescription drugs to cover up the pain that can result from football-related injuries. Or they may take performance-enhancing drugs (PEDs), like anabolic steroids, trying to make themselves stronger and (they hope) play a better game.

    The NFL’s drug policy—which it developed along with the NFL Players’ Association (NFLPA)—takes a stand against PEDs as well as other substances. But the policy doesn’t score with some critics, who think it isn’t strict enough.

    No illegal kicks

    The League bans players from using, possessing, or distributing drugs like cocaine, marijuana, painkillers such as opioids, MDMA (Molly or Ecstasy), and PCP. Amphetamines are also banned unless the player has a genuine, proven need to use them for a medical condition. The policy also covers alcohol use that’s associated with breaking the law: for instance, failing an alcohol breath test.

    In 2014, the NFL and NFLPA agreed on a separate policy for PEDs. It bans players’ use of anabolic steroids, stimulants, human or animal growth hormones, and related PEDs.

    NFL players are tested for drugs at certain points throughout the season, and again at other times if a player fails a drug test, or is arrested in connection with drug use, or shows signs of drug abuse.

    Time to move the goalposts?

    If a player violates the NFL’s drug policy once, he receives 90 days of treatment and the unannounced testing. Second-time violators get two years of treatment and testing, plus a four-game suspension if they don’t stick with the treatment or they test positive. Three-time offenders who don’t stay with treatment or who have a positive test for marijuana get a 10-game suspension, and a year-long ban from the League for using other drugs.

    People who think the NFL drug policy should be tougher point to players like Josh Gordon, the Cleveland Browns’ 24-year-old wide receiver, who has already faced four suspensions (two of them lasting a year each). And in 2014, there were 41 drug-related suspensions in the League—an all-time record—and the current season may break that record.

    A lot of people look up to the players, and critics worry that when so many NFL players are violating drug policy, it sends a bad message. The League may or may not “move the goalposts” for players who use drugs—but either way, the consequences for those players are a reminder that using banned or illegal drugs for any reason is a losing game.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    Note: This post has been updated since the original posting date.

    Last week, the American Academy of Pediatrics (AAP), an organization that represents doctors who specialize in treating children and adolescents, published a statement opposing most uses of medical marijuana and the legalization of marijuana, because of the possible ways the drug can harm young people.

    You’re aware that there’s been a lot of talk about whether the government should relax its marijuana laws, or even make it legal. There are lots of strong opinions for and against. So far, voters in four states and the District of Columbia have voted to legalize adult recreational use of marijuana.

    Nearly half of the states have also passed laws allowing medical use of marijuana, even though so far there’s very little science supporting it. The Food and Drug Administration (FDA), which puts its stamp of approval on medicines, has never approved it.

    Doctors who treat young people are worried about the long-term dangers of exposure to marijuana when the brain is still growing—usually until you’re in your early 20s. Studies show that young people are especially vulnerable to becoming addicted to drugs, including marijuana. And heavy use of marijuana in the teen years has been linked with loss of IQ—which can potentially have a domino effect in a person’s life: worse grades, worse jobs, worse relationships, and so on.…

    The AAP also recommended that, in places where marijuana has already been legalized, authorities take steps to keep it out of the hands of young people and to place limits on advertising that might make it seem appealing to kids.

    Although the AAP is opposed to most medical marijuana—and especially against using marijuana to treat children and teens—it does support loosening the legal restrictions (“scheduling”) on marijuana that sometimes make it hard for researchers to study the possible health benefits of the plant and the cannabinoid chemicals it contains. More research could lead to FDA-approved drugs that use these potentially healing chemicals, but do not require smoking the plant, which can affect your lung health.

    Tell us what you think: Are these doctors right? Do you think more kids would use marijuana if it was made legal? Do you think most teens realize their brain is still growing and could be affected by marijuana use?  

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Research shows that some of the chemicals in marijuana can help people with cancer and other serious diseases. But this doesn’t mean that anyone who is sick should use marijuana. The government has approved a few medicines in pill form that have marijuana chemicals in them but don’t make you high. Only a doctor can give you these medicines. This is not the same type of marijuana that people usually smoke. Scientists are looking at ways that marijuana can help with other conditions, but it will take years of research.

  • Mechanism of Action

    woman viewing test tube

    THC, the main active ingredient in marijuana, binds to and activates specific receptors, known as cannabinoid receptors. There are many of these receptors in parts of the brain that control memory, thought, concentration, time and depth perception, and coordinated movement. By activating these receptors, THC interferes with their normal functioning.

    The cerebellum is a part of the brain involved in balance, posture, and coordination of movement. The cerebellum coordinates the muscle actions ordered by the motor cortex. Nerve impulses alert the cerebellum that the motor cortex has directed a part of the body to perform a certain act. Almost instantly, impulses from that part of the body inform the cerebellum as to how the action is being carried out. The cerebellum compares the actual movement with the intended movement and then signals the motor cortex to make any necessary corrections. In this way, the cerebellum ensures that the body moves smoothly and efficiently.

    The hippocampus is involved with memory formation. Studies suggest that marijuana affects memory by decreasing the activity of neurons in this area. Because the hippocampus is involved in new memory formation, someone under the influence of marijuana will have impaired short-term memory, and new learning may be compromised. However, most studies in humans suggest that if a person stops using marijuana, their memory abilities can recover.

    Marijuana also affects brain areas responsible for sensory perception (for example, touch, sight, hearing, taste, and smell) in the cerebral cortex. Most sensory information that comes from the body is routed through the thalamus, and then on to appropriate areas of the cerebral cortex. For example, the somatosensory cortex receives messages interpreted as body sensations, such as touch. The somatosensory cortex lies in the parietal lobe of each hemisphere. The somatosensory cortex is organized in such a way that the entire body is represented, so that it can receive and accurately interpret impulses from a specific body part. Other specialized areas of the cerebral cortex receive the sensory impulses related to seeing, hearing, taste, and smell. Impulses from the eyes travel along the optic nerve and then are relayed via the thalamus to the visual cortex in the occipital lobes. Portions of the temporal lobes receive auditory messages from the ears. The area for taste lies buried in the lateral fissure, which separates the frontal and temporal lobes. The center for smell is on the underside of the frontal lobes-smell is the only sense that is not relayed through the thalamus. Olfactory nerves carrying this information go through the olfactory bulb and directly to the cortex. Marijuana activates cannabinoid receptors in these various cortical areas, leading to altered sensory perception that users experience under the influence.

    In the late 1980’s, it was discovered that THC acted at specific receptors in the brain, which became known as cannabinoid receptors. It was then hypothesized that, because these receptors exist, there must also be a substance naturally produced in the brain that acts on them. In 1992, scientists discovered a substance that activates the THC receptors and has many of the same physiological effects as THC. The scientists named the substance anandamide, from a Sanskrit word meaning “bliss.” The discovery of anandamide opened whole new avenues of research, which led to the discovery of additional cannabinoid molecules and receptors. One of these, 2-arachidonoglycerol, is similar to anandamide, and helps control pain. Scientists continue to study the functions of anandamide and 2-arachidonoglycerol in the brain, with the hope of understanding not just how marijuana exerts its actions and why it is abused, but also how the cannabinoid system contributes to brain function under normal (non-drug) conditions.

    Marijuana’s potential medicinal effects have long been hypothesized. Indeed, oral forms of THC (e.g., marinol) are already currently available to treat nausea associated with chemotherapy and to stimulate appetite in AIDS wasting syndrome. The discovery of the brain's own THC-like substances, and their unique mode of action, should help uncover the mechanisms underlying the therapeutic potential of cannabinoids, which could then lead to the development of more effective and safer treatments for a variety of conditions, including addiction, pain, obesity, multiple sclerosis, etc.

    The following activities will help explain to students how these substances change the brain and the body.

  • The NIDA Blog Team

    This is the final post of a 3-part series on the science of medical marijuana. Check out Part 1: What’s Wrong with “Medical Marijuana”? and Part 2: Making Medicine from Marijuana.

    People who write about the health benefits of marijuana sometimes think it’s ironic that a plant containing compounds that could treat disease (like THC or CBD) is banned by the government for being unsafe. But in fact many effective, FDA-approved medicines are closely related to illegal, harmful drugs and are sometimes even made from the same sources.

    That’s because there’s a fine (and sometimes fuzzy) line between chemicals that are good for you and those that can hurt or even kill you. The Greek word pharmakon, where we get pharmacy, originally meant both “medicine” and “poison.”

    Speaking the Body’s Language

    The opium poppy is a great example. It’s the source of a drug called morphine, part of a class of drugs called opioids. Morphine is used to make heroin, a very addictive and sometimes deadly drug. But morphine is also modified to make many effective, relatively safe pain relievers prescribed widely by doctors and dentists. In fact, these opioids are our most valuable drugs for pain relief.

    Another example is cocaine, from the coca plant. It's part of a class of drugs called stimulants. Cocaine is an especially dangerous, addictive stimulant, but it's closely related to medications used to treat people with attention deficit hyperactivity disorder (ADHD) and other conditions.  Sometimes it's also used as an anesthetic.

    The thing that makes a drug a drug is its ability to speak the body’s language—specifically, to interact with one of the many chemical signaling systems that cells use to talk to each other. Both heroin and cocaine are able to do that, fluently.

    Same with marijuana: Its cannabinoid chemicals speak the body’s own endocannabinoid language.

    Parlez-Vous Endocannabinoid?

    Nerve cells use chemicals called neurotransmitters to send each other messages, and there are several different kinds of neurotransmitters. Similar chemicals in plants or in foods can interact with these neurotransmitter systems because their molecules are very similar to the ones produced naturally in the human body.

    Morphine from the poppy plant is able to work in a peson's nervous system because it closely resembles the body’s own natural pain-relieving opioid chemicals—the endorphins that cause a “runner’s high.” (The “endo” in endorphin or endocannabinoid means “from inside”—that is, inside your body.)

    Cocaine and related stimulants work with your own neurotransmitter dopamine, which naturally keeps you focused on rewarding activities.

    And the THC in marijuana interacts with the endocannabinoid signaling system used by the body’s own cannabinoid chemicals—such as anandamide—in brain circuits that control a wide range of things including pleasure, memory, thinking, concentration, movement, coordination, and even how you perceive time. That’s why THC can interfere with these abilities when people smoke marijuana either to get high or to treat a medical condition.

    The endocannabinoid system also is involved in things like appetite and pain, which is why THC has been made into an effective medication for helping treat nausea and loss of appetite in AIDS and cancer-chemotherapy patients. And it's why THC may, in the future, be prescribed for treating pain.

    So, there’s nothing special about marijuana: It’s one of many plants that contain substances that can be both beneficial and harmful, depending on how they're used.

    Update: Read the blog post, “How Legal Is Marijuana?

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Teens get answers from experts to their questions about drugs and alcohol during NDAFW Chat Day 2016.

    The NIDA Blog Team

    How much do you really know about why people become addicted to drugs, whether marijuana can be medicine, and what causes a hangover?

    Every January, the National Institute on Drug Abuse (NIDA) hosts a chat day for National Drug and Alcohol Facts WeekSM (NDAFW). This year, NIDA scientists answered more than 1,600 questions from teens and others about drug and alcohol use. Here are a few of our favorites from this year’s questions; a link to the full chat transcript is on our NDAFW page.

    1. Why do some people become addicted, while others don’t?

    Great question, and a hard one. We don’t fully understand yet why this is so. We know that genes play a part, because an inclination for addiction can run in families, and because different strains of mice, rats, and other animals differ in how readily they develop addiction-like behaviors after they’re exposed to drugs.

    We also know that a person’s environment plays a part in addiction. For example, what are the factors that encourage someone who has tried a drug to keep on taking it to the point where they can’t stop? Many scientists are trying to untangle the answers so that we can find better ways to prevent and treat addiction. 

    See these videos on how anyone can become addicted, and why drugs are so hard to quit.

    Update: Read more on what increases the risk of having a drug problem.

    2. What can cause a hangover?

    There are several reasons why people experience hangovers from drinking. One component is dehydration. Alcohol causes the body to get rid of too much fluid, and the dehydration that results can cause headaches, nausea, thirst, and other symptoms of hangovers.

    While some people think that alcohol helps a person sleep, it actually disrupts sleep, and that can contribute to the grogginess that accompanies hangovers. 

    3. What properties in drugs make them addicting?

    Different drugs act on the brain in different ways, but they all cause release of the neurotransmitter dopamine in the brain’s reward area, which is what causes the pleasurable sensation (the high). Once a person uses a drug repeatedly, their brain starts to adjust to these surges of dopamine; the brain cells (neurons) make fewer dopamine receptors, or they simply produce less dopamine.

    The result is a lower amount of “dopamine signaling” in the reward area—it’s like “turning down the volume” on the reward signal. Then the person may start to find natural “rewards”—like food, relationships, or sex—less pleasurable; that’s one of the signs of addiction

    Also, reduced dopamine signaling in the brain’s prefrontal cortex, which governs our ability to inhibit (slow down or stop) our impulses, makes it harder to resist the urge to take drugs even if a person would like to quit. Learn more about how drugs affect your brain and body.

    4. Does marijuana use lead to the use of other drugs?

    The “gateway drug” concept—where using one drug leads a person to use other drugs— generates a lot of controversy. Researchers haven’t found a definite answer yet, but as of today the research does suggest that, while most people who smoke marijuana do not go on to use other drugs, most teens who do use other illegal drugs try marijuana first.

    For example, the risk of using cocaine is much greater for those who have tried marijuana than for those who have never tried it. However, this risk is also greater for people who have used alcohol and tobacco.

    Animal studies suggest that because the teen brain is still developing, using marijuana, alcohol, or tobacco in your teen years (or earlier) may alter your brain’s reward system (see the answer to #3 above), and that may put teens at higher risk of using other drugs. In addition, using marijuana puts children and teens in contact with people who use and sell other drugs, increasing the risk of additional drug use.

    5. Is medical marijuana good for you?

    The marijuana plant has not been approved by the FDA for the treatment of any medical condition. A pill form of THC (the main chemical in marijuana that affects the brain) is already available for certain conditions, such as nausea associated with cancer chemotherapy and weight loss in patients with AIDS.

    Early research suggests that some of the active ingredients in marijuana, like THC and cannabidiol (CBD), might be able to help treat conditions and diseases like epilepsy, cancer, or addiction. Scientists are studying THC and CBD to try to develop new medications. However, smoked marijuana is unlikely to be an ideal medication because of its negative health effects, including the risk of addiction and the damage that smoking can do to your lungs.

    6. Can drugs affect animals?

    Yes. Chemicals can have different effects in different animals—for instance, chocolate is delicious to humans and poisonous to dogs—so even small amounts of a drug could be very harmful for your pet. Alcohol can cause a dog to suffer dangerous drops in blood pressure, blood sugar, and body temperature, to have seizures, and to stop breathing.

    In dogs and cats poisoned by marijuana, signs may be seen within 3 hours, such as a lack of energy, low heart rate, low blood pressure, respiratory depression, hyperactivity, seizures, vomiting, and coma. Also, your pet wouldn’t understand that it had been given a drug, and the sensations that might feel like a “high” to a human would be a very scary experience for an animal.

    7. How can I help someone if they are on drugs?

    One of the best things you can do for a friend with a serious drug problem is let them know you are there to support them. Tell them you’re concerned about their drug use and encourage them to seek help from a trusted adult; maybe a teacher, coach, parent, or counselor can help. 

    You can also help by being a strong positive influence; help them get involved in non-drug-using activities like joining a club, playing music, or playing a sport. However, if your friend is becoming a negative influence in your life, you might have to step away from the friendship for a while.

    If you feel your friend is a danger to himself or herself, or to others, it is important to tell a trusted adult right away; it could save your friend’s life. See NIDA’s “Step by Step Guide” for teens and young adults.

    8. Are video games more addictive than drugs?

    No, they aren’t more addictive—for example, they don’t cause painful physical withdrawal when you stop. Technically, video games wouldn’t be considered addictive. But they do act on some of the same systems in the brain as addictive drugs. For instance, they produce bursts of dopamine (described in answer #3 above), and some people think that playing video games a lot might cause problems similar to drug use, such as being unable to get satisfaction from other things in life. 

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    With so much hype about marijuana legalization and the “drug war,” it’s easy to think that marijuana is just a modern phenomenon (or invented by the hippies). But the cannabis (or hemp) plant has had a long—really long!—history. And while the plant, and the way it is used, has changed a lot over the centuries, it’s interesting to take the long view of marijuana and look back at its history. For this three-part series, we’ll be your tour guide of cannabis through the ages.

    Starting in Asia…

    The cannabis or hemp plant (which only came to be called marijuana in the 20th century) has a long history, going back several thousand years—first in Central Asia, then spreading east to China, south to India, and westward to Europe, the Middle East, and Africa.

    In most ancient cultures, though, “getting high” was not the main use for the plant. Hemp fiber was valued for making clothes and other textiles, and its seeds were used for food and oil. The types of plant used for these purposes had very low amounts of THC, the chemical that causes intoxication.

    The ancients did know, however, about the plant’s mind-altering properties and may have bred varieties for this purpose as well. The oldest evidence of this is the remains of burned cannabis seeds that have been found in graves of shamans—religious leaders and healers—in China and Siberia from around 500 BC.

    Ancient “Medical Marijuana”

    Shamans enlisted the aid of spirits to help their community and try to cure sickness. Sometimes this was done with the help of intoxicating substances, and it is likely that cannabis was used this way. It probably wasn’t “recreational” but was believed to be a serious religious and healing tool to be respected.

    We now know that THC can be used medically to treat nausea—in fact, two FDA-approved drugs with THC are prescribed in pill form to people who feel sick or have no appetite as a result of chemotherapy or AIDS. The ancients seem to have used cannabis to treat similar ailments. It appears in ancient medical texts from ancient Egypt, and ancient Greek physicians described using it for stomach problems.

    Cannabis as a Recreational Drug

    The oldest evidence of marijuana being used recreationally comes from an ancient Greek historian named Herodotus (484–425 BC). He described how people of a Eurasian society called the Scythians inhaled the vapor of cannabis seeds and flowers thrown on heated rocks. It might have not sounded that appealing to his Greek readers, though, who much preferred to get “high” on wine, as did the Romans later.

    The first drug to rival alcohol for popularity in Europe was tobacco, imported from America in the late 1500s. Coffee followed about a century later, imported from Africa. And although Europeans cultivated hemp and occasionally smoked cannabis, its popularity didn’t match that of alcohol, tobacco, and coffee.

    Unlike in Europe, however, cannabis (in the concentrated form called hashish) did become widely used in the Middle East and South Asia after about 800 AD. The reason has to do with the spread of Islam. The Koran strictly forbade Muslims from drinking alcohol or partaking in other intoxicating substances, but it did not specifically mention cannabis. Cannabis is prohibited in most Islamic countries today, though, as it is throughout much of the world.

    Part 2 of this series gives a brief history of cannabis in America and answers the question: Did the Founding Fathers really smoke it, as rumors have claimed?

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Laws about marijuana for recreational use vary by state but it is not legal for teens in any state.

  • Activity One


    The student will understand the effects of marijuana on the brain structures that control the five senses, emotions, memory, and judgment.

    The student will use knowledge of brain-behavior relationships to determine the possible effects of marijuana on the ability to perform certain tasks and occupations.


    Review the way marijuana use affects brain regions and structures that control the five senses, heart rate, emotions, memory, and judgment. Students will then randomly select (for example, draw from a hat) an occupation and be asked to act out, in front of the class, how marijuana use might specifically affect the performance of a person in that occupation. (Examples: airline pilot, professional basketball player, doctor, defense attorney, truck driver, construction worker, server in a restaurant, politician.) Students will identify the brain regions and structures affected by marijuana use, and describe the link between these structures and behavior.

  • Source: Don't Be A Lab Rat, a campaign sponsored by the State of Colorado.

    The NIDA Blog Team

    Marijuana has long been seen as an “alternative” drug. It was illegal for everyone, and those who used it regularly were seen as “stoners” or “hippies” or “partiers” and were somehow different than “regular” people. There was a stereotype of people who used marijuana and most people didn’t think much about it.

    And then came the rise of medical marijuana, and that began to change marijuana’s reputation. It was seen, by some, as medicine, and in some states people were able to get a prescription for it and use it to help them with specific health problems. Marijuana started to change its image. Now, along with the typical marijuana user, there were people who had medical conditions enabling them to get a prescription and use marijuana legally.

    But the biggest change in marijuana’s image is what has happened in two states, Colorado and Washington, where marijuana has been made legal for adults to use, with or without a prescription. This change pushed marijuana out of the shadows and into the spotlight.

    Marijuana is still not as popular as alcohol or tobacco in those states, but this new identity as a “legal drug” has come with a change in perception that marijuana is safe, and that the reasons it was illegal before no longer exist.

    This really worries people who dedicate their lives to the health of the public. That’s especially true when it comes to people who care about teens, whose brains are actively developing and may really be damaged by marijuana use.

    Colorado is working to counter the effects of marijuana’s image makeover by constructing human-sized rat cages to raise awareness about the effects of marijuana on young people, getting the point across that using it as a teenager is kind of like doing an experiment on your brain. Thus the campaign’s message: “Don’t be a lab rat” and questions like “Can marijuana really cause schizophrenia in teenagers? Volunteers, anyone?” The cages are displayed in places popular with kids and teens, such as a skate park and the public library.

    Tell us in comments: Do you think advertising campaigns can help teens see that marijuana is still dangerous for them to use?

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    This is the second part of an update to the post, “Using Drugs When Pregnant Harms the Baby.”

    Last week we described some of the recent scientific research about the dangers to an unborn baby’s health if the baby’s mother smokes or vapes while she’s pregnant. Now let’s look at recent discoveries about how a pregnant woman’s use of marijuana, opioids, or other drugs can affect her baby.

    Weed and pregnancy don’t mix

    You’ve probably heard that marijuana can affect a teen’s brain, which is still developing. Well, think of how it might affect a tiny baby’s brain. The active ingredient in marijuana, THC, may affect the way a baby’s brain grows and develops. A recent study found that if a pregnant mouse is exposed to marijuana, the baby mice have difficulty with solving problems, paying attention, remembering information, and socializing. The reasons aren’t clear yet, but it’s possible that THC is affecting the development of the brain cells (or neurons) that are important to those skills and behaviors.

    Another study found that pregnant women who smoke marijuana may triple their risk for a stillbirth (a baby who dies after 20 weeks or more in the womb).

    Research also discovered that using marijuana in pregnancy is associated with a 77 percent higher risk for having a baby with a low birth weight—which sometimes results in health problems such as sickness early in life or long-term learning disabilities—and can double the risk of a baby being placed in intensive care.

    These studies didn’t show that using marijuana while pregnant directly caused stillbirths and low birth weight; more research is needed to see exactly what’s behind the connection. For now, it’s important for expectant mothers to know about the significantly higher health risks associated with marijuana use.

    Pain reliever misuse = pregnancy problems

    The dramatic increase in the misuse of prescription opioid pain relievers in the last several years has brought new attention to the dangers of using them while pregnant. Researchers have found that a pregnant woman’s use of opioids can lead to neonatal abstinence syndrome (NAS), where the baby becomes dependent on the drug just as the mother does. It can also bring a higher risk for the baby to have heart defects, spine problems, and buildup of fluid in the brain (hydrocephalus).

    Other drugs: not for babies, either

    An expecting mother’s use of other kinds of drugs has all kinds of risks for the baby.

    For instance, using cocaine can lead to premature birth, low birth weight, and NAS. A pregnant woman who uses heroin has an increased risk of miscarrying, having a baby of low birth weight, and NAS.

    And let’s not forget alcohol, which can cause brain damage in an unborn child, leading to problems with development, thinking ability, and behavior.

    If you’re pregnant and you smoke, drink alcohol, or use drugs, you can get help—and help your baby in the process. Your doctor can recommend programs to help you quit, or you can call 1-800-662-HELP (4357), the Helpline of the Substance Abuse and Mental Health Services Administration (SAMHSA); visit SAMHSA’s online treatment locators; or use SAMHSA’s Step-by-Step Guides.

    Update: For the latest on marijuana use and pregnancy, read this blog post.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    Recently, the NIDA Blog Team brought the science of marijuana to life in a series of posts about the drug’s effects on your brain, perception, pets, driving, and more. Here are a few highlights!

    1. Marijuana use interferes with attention, motivation, memory, and learning. When used heavily during the teen years, it can lower grades and your IQ

    A young man looking dumbfounded.


    2.  Exposure to secondhand marijuana smoke rarely results in a contact high.

    A man looking relieved.


    3. Serving sizes for marijuana edibles are confusing—it’s easy to eat much more than a person means to, with bad side effects. 

    A women looking surprised as she is about to bite a piece of chocolate.

    For real?

    4. Marijuana doesn’t make you more creative—it just makes you think you are.

    A dog with a beret, holding a painter's palette.

    Dude, this is my masterpiece.

    5. Marijuana can make dogs ill, causing serious medical issues such as injury, dehydration, anxiety, lethargy, impaired balance, vomiting, or diarrhea. A few dogs have even died from eating it.

    A sad-looking puppy.

    No bueno.

    6. Drugged driving is dangerous, illegal, and happening more and more. The risk of being in an accident doubles after marijuana use.

    A police officer writing a ticket.

    Do you know why I pulled you over?

    7. Over three-quarters of the students surveyed in the "Monitoring the Future" study (and four-fifths of 8th graders) said they disapproved of people using marijuana regularly.

    A teen girl looking disappointed.

    Do better.

    8. Spice, also known as K2, is not fake marijuana. In fact, some effects of Spice are much more intense than those of marijuana and have even been linked to deaths.

    A teen boy looking surprised.


    9. A small number of medications that contain THC are approved by the Food and Drug Administration. They are used for treating nausea and appetite problems caused by cancer chemotherapy and AIDS. Marijuana’s other chemical—cannabidiol or CBD—also is being studied for potential medical uses, including treatment for seizures.

    A young girl dressed as a scientist.


    10. Ancient healers used cannabis in religious ceremonies—not as a party drug.

    Cannabis plant.

    That’s old school.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • If you think a friend or family member has a problem with drugs, talk to an adult you trust, like a parent, coach, or teacher, right away. Remember, treatment is available and people can get better.

    For more information, go to teens.drugabuse.gov.

    * Johnston, et al. (2018). Monitoring the Future national survey results on drug use: 1975–2017: Overview, key findings on adolescent drug use. Ann Arbor: Institute for Social Research, The University of Michigan.

  • Activity Two


    The student will understand how marijuana interferes with information transfer and short-term memory.


    Read aloud a list of 20 words to the class; then ask the students to write down as many words as they can remember. Next, have several students, stand in pairs around the room and carry on loud conversations while you read another list of 20 words to the remainder of the class. Ask students once again to write down as many of the words as they can remember. Compare the performance of the two trials. Tell the students that, like the disruptive pairs of students, marijuana interferes with normal information transfer and memory. Students will then identify the areas of the brain and structures responsible for these functions and will be reminded that marijuana alters neurotransmission in these areas. Students can also search the Internet and other sources for more research into the effects of marijuana on information transfer and memory, and then prepare a brief report summarizing their findings.

  • Photo of a marijuana leaf.

    What is marijuana

    Marijuana refers to the dried leaves, flowers, stems, and seeds from the hemp plant, Cannabis sativa. The plant contains the mind-altering chemical delta-9-tetrahydrocannabinol (THC) and other related compounds. Extracts with high amounts of THC can also be made from the cannabis plant (see "Marijuana Extracts").

    Marijuana is the most commonly used illicit drug in the United States (SAMHSA, 2014). Its use is widespread among young people. According to a yearly survey of middle and high school students, rates of marijuana use have steadied in the past few years after several years of increase. However, the number of young people who believe marijuana use is risky is decreasing (Johnston, 2014).

    Legalization of marijuana for medical use or adult recreational use in a growing number of states may affect these views. Read more about marijuana as medicine in DrugFacts: Is Marijuana Medicine? at www.drugabuse.gov/publications/drugfacts/marijuana-medicine.

    Photo of dried marijuana and joints.

    How do people use marijuana?

    People smoke marijuana in hand-rolled cigarettes (joints) or in pipes or water pipes (bongs). They also smoke it in blunts—emptied cigars that have been partly or completely refilled with marijuana. To avoid inhaling smoke, more people are using vaporizers. These devices pull the active ingredients (including THC) from the marijuana and collect their vapor in a storage unit. A person then inhales the vapor, not the smoke.

    Users can mix marijuana in food (edibles), such as brownies, cookies, or candy, or brew it as a tea. A newly popular method of use is smoking or eating different forms of THC-rich resins (see "Marijuana Extracts").

    Marijuana Extracts

    Smoking THC-rich resins extracted from the marijuana plant is on the rise. Users call this practice dabbing. People are using various forms of these extracts, such as:

    • hash oil or honey oil—a gooey liquid
    • wax or budder—a soft solid with a texture like lip balm
    • shatter—a hard, amber-colored solid

    These extracts can deliver extremely large amounts of THC to users, and their use has sent some people to the emergency room. Another danger is in preparing these extracts, which usually involves butane (lighter fluid). A number of people who have used butane to make extracts at home have caused fires and explosions and have been seriously burned.

    How does marijuana affect the brain?

    Marijuana has both short- and long-term effects on the brain.

    Image of a cross section of the brain with marked areas that are affected by THC.THC acts on numerous areas (in yellow) in the brain.

    Short-term effects

    When a person smokes marijuana, THC quickly passes from the lungs into the bloodstream. The blood carries the chemical to the brain and other organs throughout the body. The body absorbs THC more slowly when the person eats or drinks it. In that case, the user generally feels the effects after 30 minutes to 1 hour.

    THC acts on specific brain cell receptors that ordinarily react to natural THC-like chemicals in the brain. These natural chemicals play a role in normal brain development and function.

    Marijuana overactivates parts of the brain that contain the highest number of these receptors. This causes the "high" that users feel. Other effects include:

    • altered senses (for example, seeing brighter colors)
    • altered sense of time
    • changes in mood
    • impaired body movement
    • difficulty with thinking and problem-solving
    • impaired memory
    Silhouette of a seated young male, hunched over with his head resting in his hand.

    Long-term effects

    Marijuana also affects brain development. When marijuana users begin using as teenagers, the drug may reduce thinking, memory, and learning functions and affect how the brain builds connections between the areas necessary for these functions.

    Marijuana’s effects on these abilities may last a long time or even be permanent.

    For example, a study showed that people who started smoking marijuana heavily in their teens and had an ongoing cannabis use disorder lost an average of eight IQ points between ages 13 and 38. The lost mental abilities did not fully return in those who quit marijuana as adults. Those who started smoking marijuana as adults did not show notable IQ declines (Meier, 2012).

    A Rise in Marijuana’s THC Levels

    The amount of THC in marijuana has been increasing steadily over the past few decades (Mehmedic, 2010). For a new user, this may mean exposure to higher THC levels with a greater chance of a harmful reaction. Higher THC levels may explain the rise in emergency room visits involving marijuana use.

    The popularity of edibles also increases the chance of users having harmful reactions. Edibles take longer to digest and produce a high. Therefore, people may consume more to feel the effects faster, leading to dangerous results.

    Dabbing is yet another growing trend. More people are using marijuana extracts that provide stronger doses, and therefore stronger effects, of THC (see "Marijuana Extracts").

    Higher THC levels may mean a greater risk for addiction if users are regularly exposing themselves to high doses.

    What are the other health effects of marijuana?

    Marijuana use may have a wide range of effects, both physical and mental.

    Physical effects

    • Breathing problems. Marijuana smoke irritates the lungs, and frequent marijuana smokers can have the same breathing problems that tobacco smokers have. These problems include daily cough and phlegm, more frequent lung illness, and a higher risk of lung infections. Researchers still do not know whether marijuana smokers have a higher risk for lung cancer.
    • Increased heart rate. Marijuana raises heart rate for up to 3 hours after smoking. This effect may increase the chance of heart attack. Older people and those with heart problems may be at higher risk
    • Problems with child development during and after pregnancy. Marijuana use during pregnancy is linked to increased risk of both brain and behavioral problems in babies. If a pregnant woman uses marijuana, the drug may affect certain developing parts of the fetus’s brain. Resulting challenges for the child may include problems with attention, memory, and problem-solving. Additionally, some research suggests that moderate amounts of THC are excreted into the breast milk of nursing mothers. The effects on a baby’s developing brain are still unknown.

    Mental effects

    Long-term marijuana use has been linked to mental illness in some users, such as:

    • temporary hallucinations—sensations and images that seem real though they are not
    • temporary paranoia—extreme and unreasonable distrust of others
    • worsening symptoms in patients with schizophrenia (a severe mental disorder with symptoms such as hallucinations, paranoia, and disorganized thinking)

    Marijuana use has also been linked to other mental health problems, such as:

    • depression
    • anxiety
    • suicidal thoughts among teens

    Is marijuana addictive?

    Contrary to common belief, marijuana can be addictive. Research suggests that about 1 in 11 users becomes addicted to marijuana (Anthony, 1994; Lopez-Quintero 2011).This number increases among those who start as teens (to about 17 percent, or 1 in 6) and among people who use marijuana daily (to 25-50 percent) (Hall, 2009a; Hall, 2009b).

    How Does Marijuana Affect a User’s Life?

    Compared to nonusers, heavy marijuana users more often report the following:

    • lower life satisfaction
    • poorer mental health
    • poorer physical health
    • more relationship problems

    Users also report less academic and career success. For example, marijuana use is linked to a higher likelihood of dropping out of school (McCaffrey, 2010). It is also linked to more job absences, accidents, and injuries (Zwerling, 1990).

    How can people get treatment for marijuana addiction?

    Long-term marijuana users trying to quit report withdrawal symptoms that make quitting difficult. These include:

    • grouchiness
    • sleeplessness
    • decreased appetite
    • anxiety
    • cravings

    Behavioral support has been effective in treating marijuana addiction. Examples include therapy and motivational incentives (providing rewards to patients who remain substance free). No medications are currently available to treat marijuana addiction. However, continuing research may lead to new medications that help ease withdrawal symptoms, block the effects of marijuana, and prevent relapse.

    Points to Remember

    • Marijuana refers to the dried leaves, flowers, stems, and seeds from the hemp plant, Cannabis sativa.
    • The plant contains the mind-altering chemical delta-9-tetrahydrocannabinol (THC) and other related compounds.
    • People use marijuana by smoking, eating, drinking, and inhaling it.
    • Smoking THC-rich extracts from the marijuana plant (a practice called dabbing) is on the rise.
    • THC overactivates certain brain cell receptors, resulting in effects such as:
      • altered senses
      • changes in mood
      • impaired body movement
      • difficulty with thinking and problem-solving
      • impaired memory and learning
    • Marijuana use may have a wide range of effects, both physical and mental, which include:
      • breathing illnesses
      • possible harm to a fetus’s brain in pregnant users
      • hallucinations and paranoia
    • The amount of THC in marijuana has been increasing steadily, creating more harmful effects for users.
    • Marijuana can be addictive.
    • Treatment for marijuana addiction includes forms of behavioral therapy. No medications currently exist for treatment.

    Learn More

    For more information on marijuana and marijuana use, visit:

    For more information on marijuana as medicine and on state laws related to marijuana, visit:

    Monitoring the Future

    Learn more about the Monitoring the Future survey, which annually measures drug, alcohol, and tobacco use and related attitudes among teenage students nationwide:

    This publication is in the public domain and may be used or reproduced in its entirety without permission from NIDA. Citation of the source is appreciated.


    Anthony J, Warner LA, Kessler RC. Comparative epidemiology of dependence on tobacco, alcohol, controlled substances, and inhalants: basic findings from the National Comorbidity Survey. Exp Clin Psychopharmacol. 1994;2:244-268.

    Hall W, Degenhardt L. Adverse health effects of non-medical cannabis use. Lancet. 2009;374:1383-1391.

    Hall W. The adverse health effects of cannabis use: what are they, and what are their implications for policy? Int J of Drug Policy. 2009;20:458-466.

    Johnston LD, O’Malley PM, Miech RA, Bachman JG, Schulenberg JE. Monitoring the Future national results on drug use: 1975-2014: Overview, Key Findings on Adolescent Drug Use. Ann Arbor, MI: Institute for Social Research, The University of Michigan; 2014.

    Lopez-Quintero C, Pérez de los Cobos J, Hasin DS, et al. Probability and predictors of transition from first use to dependence on nicotine, alcohol, cannabis, and cocaine: results of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Drug Alcohol Depend. 2011;115(1-2):120-130.

    McCaffrey DF, Pacula RL, Han B, Ellickson P. Marijuana use and high school dropout: the influence of unobservables. Health Econ. 2010;19(11):1281-1299.

    Mehmedic Z, Chandra S, Slade D, et al. Potency trends of Δ9-THC and other cannabinoids in confiscated cannabis preparations from 1993 to 2008. J Forensic Sci. 2010;55(5):1209-1217.

    Meier MH, Caspi A, Ambler A, et al. Persistent cannabis users show neuropsychological decline from childhood to midlife. Proc Natl Acad Sci USA. 2012;109:E2657-2664.

    Substance Abuse and Mental Health Services Administration (SAMHSA). Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings. Rockville, MD: Substance Abuse and Mental Health Services Administration; 2014. HHS Publication No. (SMA) 14-4887. NSDUH Series H-49.

    Zwerling C, Ryan J, Orav E. The efficacy of preemployment drug screening for marijuana and cocaine in predicting employment outcome. JAMA. 1990;264(20):2639-2643.

  • The NIDA Blog Team

    You already know the dangers of using marijuana before driving: Marijuana seriously impairs your motor skills and clouds your perception and judgment, all of which you need to safely operate a car. That’s why it’s illegal to drive high. But lots of people don’t know this … or they know it, but figure it’s okay “just this one time.” Whatever the case, it’s breaking the law, just like driving after drinking alcohol.

    Driving under the influence of marijuana is a big problem. A 2007 study by the National Highway Transportation Safety Administration found that 8.7 percent of people driving at night on a weekend had been using marijuana—4 times the percentage of drivers who had had enough alcohol to impair them.

    With all of these drugged drivers, police need an easy test to check if people have been using marijuana, like they have for alcohol. Unfortunately, there isn’t one—yet.

    A Marijuana Breathalyzer

    With alcohol, police can test a driver’s breath and tell if the person has enough in their system to impair their driving—a device called a breathalyzer. This works because alcohol leaves the body quickly.  This also means that the breathalyzer only measures alcohol that has been recently used.

    Measuring marijuana, however, turns out to be way, way more complicated.

    For one thing, marijuana can stick around in a person’s body a lot longer than alcohol. It can be detected in blood tests of heavy users as much as a month after they’ve stopped using it! So in theory, heavy marijuana users could test positive in a blood test for marijuana even if they haven’t used it in a few weeks.

    Another tricky thing with marijuana is that, after taking it, frequent users may show a higher amount of THC (marijuana’s active ingredient) in their body fluids than infrequent users do, even if the effect on their driving abilities is similar.

    This means there’s a big need for a test that can universally tell when a person has consumed marijuana during the previous few hours, when it can have its biggest impact on driving ability—whether or not he or she uses the drug frequently or just occasionally. It also needs to be easy to use by police and painless for drivers.

    Scientists are hard at work on the problem, and last fall a team of researchers at NIDA’s Intramural Research Program had a breakthrough: a first successful test of a marijuana breathalyzer.

    Getting High for Science

    In their research study, the scientists had a group of frequent marijuana-using adults and a comparison group of occasional marijuana-using adults each smoke a single marijuana cigarette (with an exactly measured dose of THC) and then provide breath samples using a device called SensAbues. Both groups tested positive up to an hour later, and frequent users tested positive 2 hours later.

    So far it’s not perfect, and even though the collection device is very portable, the equipment to test the results isn’t, so there are still some hurdles. But it’s one step closer to making the roads safer from drugged drivers.

    Tell us what you think in comments: Do you think if the police had a marijuana breath test, it would deter people from using marijuana before driving?

    Check out these PSAs from Colorado reminding residents that while recreational use of marijuana is legal—driving under the influence of marijuana is illegal.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    In Part 1, we showed how the cannabis (hemp) plant spread from Asia to other parts of the world thousands of years ago, mainly because of its usefulness as a fiber and a grain. But as in ancient times, today some people used it for healing and some used it as a recreational drug. Now we’ll look at cannabis in America from Colonial times until the start of the 20th century, and lay to rest one of the biggest myths about the history of this drug.

    Did the Founding Fathers Smoke It?

    The cannabis or hemp plant has been an important source of grain and fiber for thousands of years. It was brought to North and South America by European colonists in the 1500s. Hemp fiber was widely used for making sails, rope, clothing, paper, and other valuable commodities, and the growing of hemp was encouraged by the American colonies.

    There is a popular story you might have heard that the Founding Fathers of our nation smoked hemp. You might even see Thomas Jefferson quoted as saying: "Some of my finest hours have been spent on my back veranda, smoking hemp and observing as far as my eye can see."

    In fact, that quote is completely made up. None of his writings include it (or anything like it); it was falsely attributed to him—no doubt by a marijuana fan—in recent times, and it has lived a life of its own on the Internet along with lots of other made-up “facts.”

    Jefferson, along with George Washington and Benjamin Franklin, did grow hemp on their farms, as did most people who owned land, but there’s no direct evidence they ever smoked it. The amount of the psychoactive (mind-altering) chemical THC in most hemp at the time was probably too low anyway to become intoxicated from it. When Colonial Americans smoked anything, it was mainly tobacco—the drug that was also a big part of America’s economy during those times.

    Cannabis From the Druggist

    Cannabis was not widely used recreationally in the United States until the 20th century, but in the 1800s it was used as a medicine. In the 1830s, an Irish doctor in India found that cannabis extracts (not the smoked kind) could lessen the terrible vomiting of people suffering from the often fatal disease cholera. His discovery spread, and by the late 1800s, cannabis extracts were commonly sold by American druggists (pharmacists) for ailments, including stomach problems.

    Using cannabis extracts to treat digestive symptoms makes some sense, scientifically. We now know that THC is able to lessen nausea, as well as promote hunger, by interacting with areas of the brain that regulate those functions, like the brainstem and hypothalamus. Today, two FDA- approved THC-based drugs taken as pills are prescribed to treat the nausea caused by cancer chemotherapy and the loss of appetite that causes “wasting syndrome” in AIDS patients.

    “Snake Oil”

    But 19th-century doctors and druggists also touted cannabis extracts as beneficial for a long list of other problems, ranging from cough, fever, rheumatism, asthma, and diabetes to venereal (sexually transmitted) diseases, like gonorrhea.

    This was still before modern medicine, when lots of herbal products (and even animal products like oil made from rattlesnakes) were sold as “cures” for every disease under the sun. These products were usually ineffective, occasionally harmful, and frequently (as with cannabis and opium extracts) even abused.   

    In 1906, Congress passed the Pure Food and Drug Act, requiring that cannabis and other herbal products be accurately labeled. This was the beginning of laws regulating the sale of cannabis. In later years, some states passed more restrictive laws on cannabis-based medicines as more and more people realized that they could be habit-forming.

    Stay tuned for the final installment of our History of Marijuana series, and find out how cannabis started to be called marijuana.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • (Music)

    [Dr. Volkow speaking]

    Vaping becomes very appealing for teenagers because to start with its new technologies, a gadget and some of these gadgets are actually very sleek and cool-looking so it's basically you get conditioned to the gadget.

    On top of this, these devices are delivering whether it's nicotine or THC flavors.

    And flavors are a very powerful way to conditioned you to other stimulants, so anything that's ultimately very basic into the way that we get conditioned to food - through flavors and smells.

    So, here you have a device that has a new technology, the appeal of being it cool, and then on top of that it has these very tasty flavors that then become appealing on themselves.

    Then you put in nicotine, which is going to make everything more reinforcing because nicotine is a drug that activates that dopamine neuron.

    And dopamine neurons are there in your brain to assign something as salient - as worthwhile, as motivating and... then the flavor is good and then you have nicotine, which enhances that it makes it even more salient and that is really a terrible combination for accelerating the addictiveness of a product.

    The other appealing component for a teenager and of great concern is that you can use the vaping devices to deliver a 9THC which is the active ingredient of marijuana the reason why people get high on it. But you can put it in a concentrate that's almost a hundred percent.

    That vaping is now the way by which teenagers are getting cannabinoids into their system in a way that's actually going to have a higher purity and therefore may be associated with more even worse adverse effects.


  • Activity Three


    The student will learn more about the important role of the cerebellum.


    Explain that the cerebellum is involved in balance, coordination, and a variety of other regulatory functions. Marijuana affects the cerebellum, resulting in impairments in coordination of motor behavior and reaction time. Students will search the Internet and other sources for more information about the role and function of the cerebellum and will make a list of ways that disrupting the function of the cerebellum would affect their day-to-day behavior.

  • 2014’s Monitoring the Future survey of drug use and attitudes among American 8th, 10th, and 12th graders continued to show encouraging news about youth drug use, including decreasing use of alcohol, cigarettes, and prescription pain relievers; no increase in use of marijuana; decreasing use of inhalants and synthetic drugs, including K2/Spice and bath salts; and a general decline over the last two decades in the use of illicit drugs. However, the survey highlighted growing concerns over the high rate of e-cigarette use and softening of attitudes around some types of drug use, particularly decreases in perceived harm and disapproval of marijuana use.

    Top Drugs among  8th and 12th Graders, Past Year Use


    The 2014 survey showed continued declines in alcohol use by all grades. Nine percent of 8th graders, 23.5 percent of 10th graders, and 37.4 percent of 12th graders reported past-month use of alcohol, which was significantly lower than in 2009, when rates were 14.9 percent, 30.4 percent, and 43.5 percent, respectively. There was also a significant five-year drop in binge drinking (five or more drinks in a row in the previous 2 weeks) by seniors: 19.4 percent reported binge drinking in 2014, whereas 31.5 percent had reported the practice at its peak in 1998.

    Tobacco and e-Cigarettes

    Cigarette smoking by youth continues to drop and is currently at its lowest rate in the survey’s history. Only 1.4 percent of 8th graders reported smoking every day in 2014, compared to 2.7 percent in 2009; 3.2 percent of 10th graders reported smoking daily, compared to 4.4 percent in 2013 and 6.3 percent in 2009; and 6.7 percent of high school seniors reported smoking daily in 2014, down from 8.5 percent in 2013 and 11.2 percent in 2009. In 1997, at its peak, nearly a quarter of seniors were daily smokers.

    However, other forms of tobacco remain popular. In 2014, past-year hookah use continued to increase among 12th graders to 22.9 percent—the highest rate since 2010, when the survey started capturing this type of tobacco use.

    Also popular among teens is the use of e-cigarettes, which was measured for the first time in 2014. Use of e-cigarettes in the past 30 days was reported by 8.7 percent of 8th graders, 16.2 percent of 10th graders, and 17.1 percent of 12th graders. Only 14.2 percent of 12th graders view regular e-cigarette use as harmful. The nicotine in e-cigarettes is vaporized and inhaled (not smoked), but the health impact of e-cigarette use is not yet clear, nor do we know if e-cigarette use makes it more likely for people to use conventional cigarettes or other tobacco products. Survey findings show that while most e-cigarette users have also smoked conventional tobacco products, approximately 2.9 percent of 8th graders, 4.5 percent of 10th graders, and 3.8 percent of 12th graders who report past month use of e-cigarettes deny ever using tobacco cigarettes or smokeless tobacco.

    Illicit Drugs

    Use of any illicit drug has generally declined over the past two decades. Past-year use of illicit drugs for all grades combined was 27.2 percent in 2014, down from its peak at 34.1 percent in 1997. The MTF survey also shows a decline in the perceived availability of most substance over the past few years, including alcohol, cigarettes, marijuana, powder cocaine, crystal methamphetamine, and prescription painkillers.


    Marijuana use remained stable in 2014, even though the percentage of youth perceiving the drug as harmful went down. Past-month use of marijuana remained steady among 8th graders at 6.5 percent, among 10th graders at 16.6 percent, and among 12th graders at 21.2 percent. Close to 6 percent of 12th graders report daily use of marijuana (similar to 2013), and 81 percent of them said the drug is easy to get. Among 8th graders, there was a drop in perceived availability in 2014, with 36.9 percent saying it is easy to get marijuana, compared to 39.1 percent in 2013.

    Percent of Students Reporting Use of Marijuana in Past YearPercent of Students Reporting Use of Marijuana in Past YearSource: University of Michigan, 2014 Monitoring the Future Study

    Although marijuana use has remained relatively stable over the past few years, there continues to be a shifting of teens’ attitudes about its perceived risks. The majority of high school seniors do not think occasional marijuana smoking is harmful, with only 36.1 percent saying that regular use puts the user at great risk, compared to 39.5 percent in 2013 and 52.4 percent in 2009. However, 56.7 percent of seniors say they disapprove of adults who smoke it occasionally, and 73.4 percent say they disapprove of adults smoking marijuana regularly.

    Percent Perceiving Great Risk of Smoking Marijuana RegularlyPercent perceiving great risk of smoking marijuana regularlySource: University of Michigan, 2014 Monitoring the Future Study

    Marijuana use continues to exceed cigarette use in all three grade levels. In 2014, 21.2 percent of high school seniors had used marijuana in the past 30 days, whereas only 13.6 percent had smoked cigarettes.

    Prescription and Over-the-Counter Drugs

    Misuse and abuse (or “non-medical use”) of prescription and over-the-counter drugs continues to decline among the nation’s youth. Past-year use of the opioid pain reliever Vicodin has dropped significantly over the past 5 years; 4.8 percent of 12th graders used Vicodin for non-medical reasons in 2014, compared to 9.7 percent in 2009. Past-year use of narcotics other than heroin (which includes all opioid pain relievers) among high school seniors dropped from 7.1 percent in 2013 to 6.1 percent in 2014; 9.5 percent of seniors had reported past-year use of these drugs in 2004.

    Past-year non-medical use of the stimulants Adderall and Ritalin (often prescribed for ADHD) remained relatively steady in 2014, at 6.8 percent and 1.8 percent respectively for high school seniors. The survey continues to show that most teens get these medicines from friends or relatives; a smaller percentage misuse or abuse pills that had been prescribed for them for a medical problem. Although teens did not misuse or abuse prescription stimulants at higher rates than in past years, there has been a decline in teens’ perceptions the risks of doing so. In 2014, 55.1 percent of seniors saw regularly taking prescription amphetamines as harmful, down from 69.0 percent in 2009.

    In 2014, there was also a significant drop in the past-year use of cough/cold medicines containing dextromethorphan (DXM) among 8th graders, with only 2.0 percent using them for non-medical reasons, down from 2.9 percent in 2013 and 3.8 percent in 2009.

    Other Illicit Drugs

    Past-year use of MDMA (also known as ecstasy or “Molly”) saw a significant decline among 10th graders to 2.3 percent in 2014, from 3.6 percent in 2013 and 6.2 percent in 2001, when it peaked. Past-year use of heroin remained very low in all three grades despite increased use among adults over 26 years of age in 2013.1

    There has been a considerable decline in past-year use of synthetic cannabinoids (“K2/Spice,” sometimes misleadingly called “synthetic marijuana”) in the two years the survey has been tracking their use. Only 5.8 percent of 12th graders reported using K2/Spice in 2014, compared to 7.9 percent in 2013 and 11.3 percent in 2012. This was associated with an increase in the perceived risk of taking synthetic marijuana once or twice among 12th graders. Use of the hallucinogen salvia also dropped significantly among 12th graders in 2014 to 1.8 percent, from 3.4 percent in 2013.

    Another harmful synthetic drug, bath salts (synthetic stimulants), was added to the survey in 2012; past-year use of bath salts remained low in 2014, and dropped considerably among 8th graders, to 0.5 percent, compared to 1 percent.


    Current, past-year, and lifetime use of inhalants among 10th and 12th graders is at its lowest levels in the history of the survey. Rates of inhalant use are traditionally highest among the youngest adolescents (unlike most other drugs); in 2014, 5.3 percent of 8th graders reported using inhalants in the past year, down from 8.1 percent in 2009 and 12.8 percent in 1995, when use peaked.

    Learn More

    Complete MTF survey results are available at www.monitoringthefuture.org.

    For more information on the survey and its findings, also visit www.drugabuse.gov/related-topics/trends-statistics/monitoring-future.

    About the Survey

    Since 1975, the MTF survey has meas-ured drug, alcohol, and cigarette use and related attitudes among 12th graders, nationwide. In 1991, 8th and 10th graders were added to the survey. Survey participants report their drug use behaviors across three time peri-ods: lifetime, past year, and past month. Overall, 41,551 students from 377 public and private schools in the 8th, 10th, and 12th grades participated in the 2014 survey.

    The survey is funded by NIDA and con-ducted by the University of Michigan. Results from the survey are released each December.

    Other sources of information on drug use trends among youth are available:

    The annual National Survey on Drug Use and Health, conducted by the Substance Abuse and Mental Health Services Administration, gathers detailed data on drug, alcohol, and tobacco use by all age groups. It is a comprehensive source of information on substance use and dependence among Americans aged 12 and older. Data and reports can be found at www.samhsa.gov/data/population-data-nsduh.

    The Youth Risk Behavior Survey is a school-based survey conducted every other year by the Centers for Disease Control and Prevention. It gathers data on a wide variety of health-related risk behaviors, including drug abuse, from students in grades 9 through 12. More information is available at www.cdc.gov/nccdphp/dash/yrbs/index.htm.


    1. Substance Abuse and Mental Health Services Administration. Results from the 2013 National Survey on Drug Use and Health: Summary of national findings. Rockville, MD: Substance Abuse and Mental Health Services Administration; 2014. HHS Publication No. (SMA) 14-4887. NSDUH Series H-49.
  • The NIDA Blog Team

    As more communities allow medical marijuana, or decriminalize illicit marijuana, veterinarians are seeing an alarming trend. More and more dogs are arriving in emergency animal hospitals with marijuana toxicosis, or marijuana poisoning.

    A recent study in Colorado showed that 4 times as many dogs were treated for marijuana poisoning in 2010 than in 2005. Sadly, two dogs identified in that study died. Similarly, from 2008 to 2013, the Pet Poison Helpline—a poison control hotline for animals—has seen a 200% increase in calls related to pets eating marijuana.

    Most times, dogs ingest marijuana accidentally by eating a marijuana “edibles,” such as cookies or brownies, or getting into their owner’s supply. However, there are some instances where people deliberately give marijuana to their dogs or blow marijuana smoke in their faces to “get them high.” Maybe that sounds funny to people that are high, but it is very dangerous for their dog.


    While it is rare that a dog will die from marijuana poisoning, serious medical issues such as injury or dehydration can occur. Marijuana can cause dogs to become disoriented and lose coordination, leading to missteps and falls, even to the point they can’t drink water from their bowl. Symptoms of marijuana poisoning in dogs include anxiety, panting, lethargy, impaired balance (staggering or being unable to walk), drooling, vomiting, diarrhea, trembling, or extreme responses to noises, movements, or other stimulus.

    So, the next time you see one of those “dogs high on weed” videos on YouTube, give it a thumbs down. And be sure to keep your furry friends away from marijuana. Even if you believe in free choice when it comes to marijuana, you can agree that animals aren’t being given a choice when marijuana is carelessly left out for them to eat or when owners expose them for kicks. Even unintentional exposure from secondhand smoke can be harmful.

    While the debate continues about the usefulness of medical marijuana, some veterinarian groups are looking at using compounds found in the marijuana plant for animals. However, those compounds would be carefully tested and monitored by medical professionals and have no relationship to careless exposure to helpless pets.

    Tell us in comments: What would you do if you knew someone was exposing their dog or other pets to marijuana? 

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Hi there! Mind Matters (formerly referred to as Mind Over Matter) is a series that explores the ways that different drugs affect your brain, body, and life. For a limited time, hard copies of the older Mind Over Matter series with Sara Bellum are still available from our clearinghouse.

    In this issue, we are going to talk about marijuana.

    In 2017, only 13% of 8th graders had ever used marijuana in their lives.*
  • The NIDA Blog Team

    On this blog, we often get comments from people claiming that marijuana isn’t addictive. A lot of people seem to think marijuana is different from other drugs. Unfortunately, it’s not the case: Just like with other drugs (including alcohol and nicotine), you can get addicted to marijuana—especially if you use it during your teen years.

    Dependence vs. Addiction

    Drug "dependence" means needing a drug to feel physically okay. If a person is dependent on a drug, having enough of a supply is always important to them. However, being dependent doesn’t necessarily mean they’re addicted. For example, many people can be dependent on a medication prescribed by their doctor without being addicted to it.

    The difference is that people who are addicted start to think about the drug all the time and make it a larger priority than other things in their life. They often make bad decisions that work against their health and their overall well-being. In the case of a medication, they may start to abuse it (use it differently than how the doctor prescribed): taking more of it, or crushing it and injecting it. Or in the case of a drug like marijuana, they'll be unable to stop using it even though it's causing problems with school, a job, or relationships. People with an addiction are often unable to see—or admit—that this is happening.

    That Bad Feeling …

    … is called withdrawal. A person with drug dependence will experience withdrawal if they completely stop using the drug all at once. Withdrawal is what leads a lot of people who are addicted to a drug to relapse—meaning, they've tried to quit, but they start taking the drug again.

    A new study in the Journal of Addiction Medicine shows that teens who use marijuana heavily can experience withdrawal when they stop using it. In a study of teens receiving drug abuse treatment at an outpatient clinic, nearly half of them (40 percent) experienced symptoms of withdrawal when they stopped using marijuana.

    Not Just a Crummy Day

    From portrayals in movies and on TV of people addicted to heroin, people have an image of drug withdrawal as sweating, shaking, and being curled up in bed with unbearable pain. Marijuana withdrawal is a lot more subtle, but every bit as real.

    The main mental symptoms of marijuana withdrawal include:

    • Being irritable
    • Feeling anxious or worried
    • Feeling depressed
    • Being restless
    • Having trouble sleeping at night and feeling tired during the day
    • Having low appetite or losing weight

    Some people having marijuana withdrawal might not realize it. Some of the symptoms just contribute to being in a lousy mood, and it’s often easy to blame that feeling on other people annoying you or just having a bad day. You can also have physical symptoms like:

    • Stomach pain
    • Sweatiness
    • Shakiness
    • Fever
    • Chills
    • Headache

    More Use = More Problems

    The longer a person uses marijuana, the more likely they are to have withdrawal symptoms when they aren’t using it. In the Journal of Addiction Medicine study, teens who had marijuana withdrawal symptoms were more likely than other marijuana users to have problems like difficulties at school or at work or trouble with relationships or money. They were also more likely to have other signs of marijuana dependence and mood disorders like depression.

    And teen users who suffer marijuana withdrawal are more likely to experience marijuana addiction than adults. One in six teens who try marijuana will get addicted to it, and that goes up to as many as one-half of teens who use it every day. 

    If you’re worried you may have a problem with marijuana or any other drug, this page may help answer your questions and let you know what to do to get help.

    Tell us in the comments: Do you know any regular marijuana users who stop using marijuana and experience the withdrawal symptoms described in this post?

    To learn more about marijuana, check out the blog posts “Secondhand Marijuana Smoke?” and “What’s Wrong With ‘Medical Marijuana’?”

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • ©Shutterstock/Igor Levin

    The NIDA Blog Team

    You might have heard of the drug Spice (also known as K2). It’s sometimes called “fake weed” or “synthetic marijuana,” because some of the chemicals in Spice are similar to the ones in marijuana. But it’s a myth that Spice is the same as marijuana; in fact, Spice is very different.

    Spice contains chemicals that are sprayed on dried plant material; then, the material can be smoked or used in liquid form for e-cigarettes or vaporizers. Scientists call the chemicals synthetic cannabinoids.

    Using Spice is a gamble.

    It’s impossible to know exactly what’s in Spice.

    The amount and type of chemicals in each batch of the drug varies, partly because people who make it are constantly changing the ingredients. Every time certain chemical compounds are banned, makers can sometimes get around the new laws by creating different compounds that act in a similar way.

    In fact, in 2014, law enforcement officials reported 177 different types of synthetic cannabinoid compounds.

    Spice has unpredictable effects.

    The health effects of Spice are also different from—and often stronger than—the effects of marijuana.

    Spice acts on many different receptors in the brain. It produces unpredictable effects that can be dangerous. Spice can cause:

    • Nausea and vomiting
    • Rapid heart rate
    • Paranoia
    • Hallucinations
    • Violent behavior
    • Suicidal thoughts

    In 2016, there were 2,695 calls to poison control centers for harmful effects from Spice.

    The bottom line: Spice might look like marijuana, and drug dealers might call it fake weed, but those are gimmicks to get you to use it.  

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Sara Bellum

    Knowing the health risks that come with using or abusing drugs convinces most teens (and adults) to stay away from them. But what if you don’t think certain drugs are unsafe?

    In December 2012, NIDA released the results of the 2012 Monitoring the Future (MTF) study (involving 8th, 10th, and 12th graders). The findings show that fewer teens believe abusing marijuana and Adderall is bad for their health. This belief is contributing to higher rates of abuse of these drugs.


    Graph of perceived risk of marijuana use among 12th graders. Over the last 5 years, current (past-month) marijuana use has gone up significantly among 10th and 12th graders. In fact, current marijuana use among high school seniors is at its highest point since the late 1990s. Daily marijuana use has climbed significantly across all three grades. The study also found that fewer teens now believe using marijuana is harmful.

    However, the science shows otherwise. People who smoke a lot of pot risk injuring their lungs with the chemicals found in the smoke, and may also experience depression and anxiety. New research has found smoking marijuana heavily in your teen years and continuing into adulthood can actually lower your IQ!


    Also in the 2012 MTF study, 12th graders reported increased nonmedical use of the prescription stimulant Adderall—commonly prescribed to people with ADHD. As with marijuana, fewer teens perceive that abusing Adderall is risky. If that trend continues, Adderall abuse will probably continue to increase as well.

    Abusing a stimulant medication like Adderall may increase blood pressure, heart rate, and body temperature; decrease appetite and sleep; and cause feelings of hostility and paranoia.

    Perception of Risk

    Studies have found that when teens think a drug can be harmful, they are less likely to abuse it. In the case of marijuana and Adderall, it appears that some teens don’t see the risk. Tell us: Do you think these drugs are dangerous? If you agree they are, what can we do to help people you know get the message?

    Other notable findings from the 2012 MTF study:

    • Most of the top drugs abused by 12th graders are legal substances, like alcohol, tobacco, over-the-counter drugs, and prescription drugs.
    • Abuse of synthetic marijuana—K2 or Spice—remained stable in 2012.
    • Most teens who abuse prescription drugs get them from family and friends.
    • Alcohol use and cigarette smoking are steadily declining.

    Check out this cool infographic to learn more.

    These drug abuse estimates come from the Monitoring the Future study’s national surveys of approximately 45,000 students in about 400 secondary schools each year. View all of the 2012 data.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    Not many people would say with a straight face that drugs like heroin or methamphetamine are good for you. And who would claim that those drugs could help you be more successful in life? 

    But there are lots of people who think marijuana is different from other drugs. For example, we’ve already talked in this blog about the idea that it may have medical uses. (The jury is still out on that one.)

    Some users even say marijuana’s mind-altering effect—the “high”—is also beneficial. They claim using the drug chills them out, expands their mind, and makes them more creative. Since the 1960s, marijuana has had this mystique as an aid to the artistic life.

    What does science say about that?

    Getting Creative with the Facts

    Many studies over the years have found that marijuana indeed makes users perceive themselves as having more creative thoughts and ideas—which would help explain why so many artists and musicians tout its benefits.

    But perception isn’t always the same as reality—and we know that marijuana alters perceptions! In fact, the research on cannabis and creativity suggests that even if users feel more creative, it’s actually an illusion. People may even be less creative after using it.

    For example, a new study of almost 60 cannabis users in The Netherlands looked at the effects of the drug on a measure of creativity called divergent thinking—which means the ability to brainstorm, think flexibly, and come up with original solutions to problems. After inhaling a high or low dose of vaporized cannabis, or a vapor with the same odor and taste but no THC (the chemical that causes the high), the participants took a test that asked them to come up with as many creative uses for two common items (like a pen or a shoe) as they could.

    The results surprised even the researchers: low doses of cannabis did not have any effect on the participants’ ability to think creatively, compared to not taking cannabis. And high doses actually lowered their creativity—by a lot.

    It seems that feeling creative and being creative really aren’t the same thing.

    Yet it's also true that your expectations about a drug do matter. Different studies have shown that people who are unknowingly given a placebo (something with no drug in it) instead of a drug (or alcohol) will act or perform in ways that correspond to how they expect the drug to affect them.

    Marijuana on Your Mind

    One study, for example, found that regular marijuana users who ate biscuits containing marijuana were less creative than a control group who didn’t eat any biscuits, and that both of those groups were less creative than a group who ate biscuits they thought contained marijuana but were actually a placebo.

    It goes to show that your mind, including your beliefs about drugs, have a lot more power than you think. You don’t have to take the drug to get the effect you expect—in fact, it works best if you don’t!

    What do you think? Do you know people who take marijuana (or other drugs) to help them be more creative? Do you think it helps or hurts them? Let us know in comments.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Image by NIDA.

    The NIDA Blog Team

    Update: On November 7, 2018, voters in four states went to the polls to decide on changes to their marijuana laws:

    • Voters in Michigan legalized the sale and use of marijuana.
    • Voters in Utah and Missouri legalized medical marijuana.
    • North Dakota did not legalize recreational marijuana.

    In total, 33 states and the District of Columbia have now passed laws legalizing marijuana in some form.

    (Information is current as of November 7, 2018.)

    Update: On Nov. 8, 2016, voters in eight states made changes to their marijuana laws, according to uncertified results. California, Maine, Massachusetts, and Nevada legalized marijuana for adult recreational use. Arkansas, Florida, Montana, and North Dakota legalized marijuana for medical use. The details of the laws and when they go into effect vary by state.

    Original post, current as of Oct. 11, 2016:

    There’s been a lot of talk in the U.S. lately about legalizing marijuana. Maybe you’ve heard stories in the news about some states that have legalized weed (or are debating whether to do that) and wondered, what does that mean for you?

    Recreational marijuana

    First, let’s get the obvious out of the way: If you’re a teen, it’s never legal to use marijuana recreationally (that is, just to get high).

    Marijuana is also still illegal under U.S. federal law, even in states that have passed laws to make it legal under state law.

    Confused yet? Okay, so what about those state laws?

    The District of Columbia and four states (Alaska, Colorado, Oregon, and Washington) allow adults to use marijuana recreationally. While the laws in these places vary, all of them prohibit people under the age of 21 from using marijuana recreationally.

    Medical marijuana

    Some research suggests that marijuana may have the potential to help treat some health conditions including pain, nausea, epilepsy, and others. But there hasn’t been enough research on the subject, and patients across the country are using marijuana strains and extracts that haven’t been fully tested or shown to be effective for their medical condition.

    So far, 25 states and D.C. have passed laws to let people use marijuana with recommendations from their doctors (and sometimes by fulfilling other requirements, like having a medical marijuana license). The federal government has decided not to challenge those laws to any great extent. But people who buy marijuana in a state where it’s legal (for medicinal or recreational use) cannot take it across state lines into a state where it is not legal. So it remains a confusing issue.

    Marijuana hasn’t been approved by the Food and Drug Administration (FDA), and that approval is necessary to grow and sell medicine in this country. But researchers are studying possible medical uses for marijuana and some of the chemicals it contains. The Drug Enforcement Administration (DEA), which enforces marijuana laws in the U.S., recently said it would increase the number of places allowed to grow the plant for research purposes in hopes of making it easier for more scientists to study marijuana.

    So just to repeat, nothing in the law has changed for teens; using weed to get high is still illegal, wherever you live in the U.S. Depending on what scientists learn about marijuana’s value as medicine, it may (or may not) become legal for more people with certain health problems.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Marijuana is made of dried leaves, flowers, stems, and seeds from the Cannabis satvia or Cannabis indica plant. Some people use marijuana to get high. You might have heard marijuana called other names, like “weed” or “pot.”

    People think that because marijuana is natural, it can’t be bad for them. But marijuana has hundreds of chemicals in it that can affect your body in many ways.

  • The NIDA Blog Team

    You may know that smoking marijuana can pose risks for a person’s physical health and brain development, especially for teens. But did you know that, for some people, it carries risks for their mental health, too?

    We don’t just mean short-term memory problems or poor judgment—those can happen for anybody who smokes marijuana. We’re talking about serious mental illness.

    Researchers have found that some marijuana users have an increased risk for psychosis, a serious mental disorder where people have false thoughts (delusions) or see or hear things that aren’t there (hallucinations). But there is still a lot to learn about whether marijuana use may lead to this loss of touch with reality, or if having a mental illness makes people more likely to use marijuana. And as with other drugs, things like the age of users, how early they started smoking pot, the amount of the drug they used, and their genetics all could make a difference in whether or not long-term problems develop.

    It’s not your jeans that matter—it’s your genes

    Regular marijuana users with a specific version of a particular gene, AKT1, are at a greater risk of developing psychosis than those who smoke it less often or not at all. How much greater? For people who smoke marijuana daily, the risk is up to seven times greater.

    The reason is that the AKT1 gene affects how much dopamine is released in your brain. Dopamine is one of our brain’s “feel-good” chemicals; it affects important brain functions such as behavior, motivation, and reward. When your brain releases dopamine (for example, after a beautiful bike ride or when you eat a delicious piece of chocolate), the release “teaches” your brain to seek out the same experience (reward) again. Some researchers believe that changes in dopamine levels are linked to psychosis.

    Another study found that adults who used marijuana when they were teenagers and who carried a specific form of another gene for the enzyme COMT (which also impacts dopamine signaling) were at a higher risk of becoming psychotic.

    Are you at risk?

    Right now, unless you’ve had your DNA tested for those specific genes, you don’t know. Many health professionals believe that in the future most of us will know much more about our genetic makeup, but for now and for regular marijuana users, it’s an unknown risk—and you won’t know until you've developed an addiction.

    Even if you don’t have those specific genes, there’s still a risk

    A psychotic event can even happen to pot smokers without these specific genes that put them at risk for long-term serious mental illness. Although rare, marijuana-induced psychosis is becoming more common as people use higher potency forms, including edibles and oil extracts.

    The bottom line? It’s important to know all the risks that can come with using marijuana.

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Sara Bellum

    Today, NIDA released the latest results from the 2013 Monitoring the Future (MTF) study, which asks more than 40,000 8th, 10th, and 12th graders about drug, alcohol, and cigarette use. The study revealed both good news and areas for concern.

    First of all, scientists are concerned that only about 40% of 12th graders—that’s 4 out of every 10 teens—believe using marijuana regularly can hurt you. That’s 60% who think marijuana is not harmful! This perception that marijuana use is “okay” is tied to the increases in teens’ use of the drug over the past several years. Science shows that regular marijuana use can be harmful to your health and your future. THC, the main psychoactive ingredient in marijuana, can damage the developing teen brain, yet teens aren’t understanding the connection between marijuana use and the brain’s ability to learn.

    Marijuana use is also putting teens at risk for car accidents—since the drug impairs motor coordination and reaction time. With medical marijuana becoming more accepted and some states making marijuana legal to use, it’s difficult to get these messages to teens.

    There’s other news that worries scientists too: Teens continue to abuse Adderall at a high rate. That drug is usually prescribed for people with ADHD—and when used as prescribed, it can really help. But more than 7% of high school seniors say they use Adderall to get high or for other nonmedical reasons.

    But the survey tells us that teens are getting smarter about a lot of drug use. Cigarette smoking and alcohol use continued to decline in 2013. Also, fewer teens used K2/Spice (sometimes called synthetic marijuana), inhalants, cocaine, and heroin. Fewer teens are abusing prescription painkillers like Vicodin, and very few teens are using bath salts.

    One last note: While cigarette smoking is down, too many teens are still “smoking” by using a hookah (water pipe)—in fact, more than 1 in 5 seniors say they have used a hookah in the past year. Tobacco is no less harmful in a hookah.

    How would you tell other teens that marijuana is, in fact, harmful to their health? How would you change their minds if they think marijuana is harmless? How would you explain to teens that smoking a hookah is just as bad for their health as smoking a cigarette?

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • The NIDA Blog Team

    Using drugs while playing pro sports will usually get a player warned, fined, or suspended. But some people think it’s time to let athletes use marijuana to treat pain from the injuries pro sports can inflict.

    Nate Jackson, who played for the Denver Broncos from 2003 to 2008, says NFL players need marijuana for medical reasons, to help players cope with the frequent injuries—or as he puts it, “to offset the brutality of the game.” In a New York Times opinion piece last year, Jackson argued that marijuana is a better option than handing injured players bottles of prescription opioids, strong pain medications that can be highly addictive. NBA player Blake Griffin has also said that pro athletes might benefit from medical marijuana to treat pain, instead of using prescription painkillers. 

    Is marijuana a good swap for opioids?

    Although prescription opioids are often addictive and can cause confusion and sleepiness, most people who use them as prescribed for acute (severe, often short-term) pain don’t develop an addiction.

    However, a 2009 study commissioned by ESPN (with additional funding from NIDA) found that a lot of NFL players may be misusing opioids during their careers, leading to long-term addiction. Since prescription opioids are chemically similar to heroin, some people who start out abusing prescription opioid pain medications end up using heroin.

    On the other hand, some studies have shown that marijuana (or THC, the active ingredient in marijuana) may help with some types of pain, such as chronic (persistent) nerve pain resulting from injury or surgery. But while the risks associated with marijuana addiction are generally not as severe as the possible risks of prescription opioid addiction, marijuana addiction can develop, as can other health problems. Using weed can impair thinking and memory, for example. Also, THC interferes with parts of the brain that control balance and coordination, which is bad news for athletes who need to be quick on their feet during games.

    THC can also impair concentration and can make people more likely to take risks. (In fact, for some athletes increased risk-taking may be part of marijuana’s appeal. In a 2011 study, researchers (some of them from NIDA) found that some athletes might be using marijuana to forget bad falls, take more risks to improve training, or work through pain.) Not to mention that playing stoned slows people down and makes them less vigilant, which could lead to more athletic injuries. Because of the drug’s health risks, the researchers said they supported banning it from sports.

    So what are players’ options to control injury-related pain?

    For now, athletes can use opioid medications for a short period of time and expect them to help with recovery from injuries. Honest conversations between doctors and their athlete-patients can help lower the risk for addiction—and if problems do develop, those conversations can help people get the professional help they need before they spiral down the black hole of addiction.

    For those athletes (and regular people, too) who have chronic pain, there is research showing that long-term use of opioid medications can actually make pain worse and can lead to addiction. But this is a hotly debated issue, and very smart people disagree with each other. Clearly, more research is needed. At the moment, it’s an individual decision between doctors and their patients on what treatments will work best.

    There are also alternative-medicine approaches for pain that some people have found helpful, such as acupuncture, some nutritional supplements, and chiropractic treatment, among others.

    Where is research (and medicine) heading?

    Marijuana might be of interest to some athletes, but it doesn’t have the NFL’s seal of approval for players looking to treat their pain. And though some states have made it legal for people to use marijuana for medical reasons, it’s important to note that marijuana is still not a medicine approved by the Food and Drug Administration, which approves medicines for the federal government. But NFL Commissioner Roger Goodell says the NFL will “follow medicine” and medical experts in the future, in deciding whether to let players use marijuana to treat head injuries.  

    You may have heard (or read on this blog) about FDA-approved medicines that use some of the chemicals in marijuana, called cannabinoids. These medicines aren’t currently approved in the U.S. for treating pain, though. However, NIDA is funding research into potential use of marijuana and cannabinoids for the treatment of pain—so depending on what the science says, this may change in the future. Stay tuned!

    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.
  • Monitoring the Future (MTF) is an annual survey of 8th, 10th, and 12th graders conducted by researchers at the University of Michigan, Ann Arbor, under a grant from the National Institute on Drug Abuse, part of the National Institutes of Health. Since 1975, the survey has measured drug, alcohol, and cigarette use and related attitudes in 12th graders nationwide. Eighth and 10th graders were added to the survey in 1991.

    Overall, 44,892 students from 382 public and private schools participated in the 2015 survey.

    First figure: Last Two Decades of Alcohol, Cigarette, and Illicit Drug Use*
    *Past-month use

    This graphic illustrates past-month use of alcohol, cigarette, and illicit drug use among 8th, 10th, and 12th graders from 1995 through 2015.

    In 2015, past-month use in each category was:

    12th graders: 35.3%
    10th graders: 21.5%
    8th graders: 9.7%

    12th graders: 11.4%
    10th graders: 6.3%
    8th graders: 3.6%

    Illicit Drugs
    12th graders: 23.6%
    10th graders: 16.5%
    8th graders: 8.1%

    Second figure: Teens are more likely to use e-cigarettes than cigarettes.*
    * Past-month use

    8th grade
    Cigarettes: 3.6%
    e-Cigarettes: 9.5%

    10th grade
    Cigarettes: 6.3%
    e-Cigarettes: 14.0%

    12th grade
    Cigarettes: 11.4%
    e-Cigarettes: 16.2%

    64.7 percent of 12th graders reported vaporizing “just flavoring” in their last e-cigarette; some didn’t know what they inhaled. E-cigs are unregulated so flavored liquid might actually contain nicotine.

    Flavoring: 64.7%
    Nicotine: 22.2%
    Marijuana or hash oil: 6.1%
    Don't know: 6.3%

    Third figure:  68.1 percent of high school seniors do not view regular marijuana smoking as harmful, but 71 percent say they disapprove of regular marijuana smoking.

    Forth figure: Prescription/Over-the-Counter (OTC) vs. Illicit Drugs*
    *The percentage of 12 graders who have used these drugs in the past year

    Despite the ongoing opioid overdose epidemic, past-year use of opioids other than heroin has decreased significantly each year over the past 5 years among the nation’s teens. Heroin use has also decreased over the past 5 years and is at the lowest rate since the MTF survey began.

    This list shows the percentage of 12th graders who have used these drugs in the past year.

    Amphetamines – 7.7%
    Adderall – 7.5%
    Opioids other than Heroin – 5.4%
    Tranquilizers – 4.7%
    Cough Medicine – 4.6%
    Vicodin – 4.4%
    OxyContin – 3.7%
    Sedatives – 3.6%
    Ritalin – 2.0%

    Illicit Drugs
    Marijuana/Hashish – 34.9%
    Synthetic Marijuana – 5.2%
    Hallucinogens – 4.2%
    MDMA (Ecstasy) – 3.6%
    Cocaine (any form) – 2.5%
    Inhalants – 1.9%
    Salvia – 1.9%

    Fifth figure: Students report lowest rates since start of the survey. Across all grades, past-year use of inhalants, heroin, methamphetamine, alcohol, cigarettes, and synthetic cannabinoids are at their lowest by many measures.

    For more information, visit us @NIDAnews or www.drugabuse.gov.

    The National Institute on Drug Abuse is a component of the National Institutes of Health, U.S. Department of Health and Human Services. NIDA supports most of the world’s research on the health aspects of drug abuse and addiction. Fact sheets on the health effects of drugs of abuse and information on NIDA research and other activities can be found at www.drugabuse.gov.

  • What is marijuana?

    Marijuana plantPhoto by NIDA

    Also known as: Blunt, Boom, Bud, Gangster, Ganja, Grass, Green, Hash, Herb, Joint, Pot, Reefer, Sinsemilla, Skunk, and Weed

    Marijuana is the dried leaves and flowers of the Cannabis sativa or Cannabis indica plant. Stronger forms of the drug include high potency strains - known as sinsemilla (sin-seh-me-yah), hashish (hash for short), and extracts including hash oil, shatter, wax, and budder.

    Of the more than 500 chemicals in marijuana, delta-9-tetrahydrocannabinol, known as THC, is responsible for many of the drug’s psychotropic (mind-altering) effects. It’s this chemical that distorts how the mind perceives the world. In other words, it is what makes you high.

    Read 10 things you can learn about marijuana.

    Strength and Potency

    The amount of THC in marijuana has increased over the past few decades. In the early 1990s, the average THC content in marijuana was less than 4 percent. It is now more than 12 percent, and much higher in some products such as oils and other extracts (see below). Scientists do not yet know what this increase in potency means for a person’s health. Some people adjust how they consume marijuana (by smoking or eating less) to compensate for the greater potency. There have been reports of people seeking help in emergency rooms with symptoms, including nervousness, shaking and psychosis (having false thoughts or seeing or hearing things that aren't there), after consuming high concentrations of THC. 

    Marijuana Extracts

    Smoking extracts and resins from the marijuana plant with high levels  of THC is on the rise. There are several forms of these extracts, such as hash oil, budder, wax, and shatter. These resins have 3 to 5 times more THC than the plant itself. Smoking or vaping it (also called dabbing) can deliver dangerous amounts of THC and has led some people to seek treatment in the emergency room. There have also been reports of people injured in fires and explosions caused by attempts to extract hash oil from marijuana leaves using butane (lighter fluid).

  • How is marijuana used?

    There are a few different ways people use marijuana:

    • smoking hand-rolled cigarettes called joints or marijuana cigars called blunts (often made by slicing open cigars and replacing some or all of the tobacco with marijuana)
    • inhaling smoke using glass pipes or water pipes called bongs
    • Inhaling vapor using devices that pull the active ingredients (including THC) from the marijuana into the vapor. Some vaporizers use a marijuana liquid extract. 
    • drinking tea brewed with marijuana or eating food with marijuana cooked into it, sometimes called edibles—such as brownies, cookies, or candy.

    These extracts made from the marijuana plant should not be confused with “synthetic marijuana,” sometimes called “K2,” “Spice,” or “herbal incense.” These synthetic drugs are laboratory-made chemicals similar to THC that are sprayed onto plant materials to make it look like marijuana, but are often much stronger and very dangerous. Unlike marijuana, their use sometimes directly results in overdose deaths. Learn more about "synthetic marijuana”.

  • What happens to your brain when you use marijuana?

    All drugs change the way the brain works by changing the way nerve cells communicate. Nerve cells, called neurons, send messages to each other by releasing chemicals called neurotransmitters. These neurotransmitters attach to molecules on neurons called receptors. (Learn more about how neurotransmitters work.) Drugs affect this signaling process.

    When marijuana is smoked or vaporized, THC quickly passes from the lungs into the bloodstream, which carries it to organs throughout the body, including the brain. Its effects begin almost immediately and can last from 1 to 3 hours. This can affect decision making, concentration, and memory for days after use, especially in people who use marijuana regularly.1 If marijuana is consumed in foods or beverages, the effects of THC appear later—usually in 30 minutes to 1 hour—and may last for many hours. Some people consume more and more waiting for the “high” and end up in the emergency room with uncomfortable symptoms from too much THC.

    As it enters the brain, THC attaches to cells, or neurons, with specific kinds of receptors called cannabinoid receptors. Normally, these receptors are activated by chemicals similar to THC that occur naturally in the body. They are part of a communication network in the brain called the endocannabinoid system. This system is important in normal brain development and function.

    Marijuana's Effects on the Brain

    Most of the cannabinoid receptors are found in parts of the brain that influence pleasure, memory, thinking, concentration, sensory and time perception, and coordinated movement. Marijuana activates the endocannabinoid system, which causes the "high" and stimulates the release of dopamine in the brain's reward centers, reinforcing the behavior. Other effects include changes in perceptions and mood, lack of coordination, difficulty with thinking and problem solving, and disrupted learning and memory.

    Learn more about how the brain works and what happens when a person uses drugs.

    1 Crean RD, Crane NA, Mason BJ. An evidence based review of acute and long-term effects of cannabis use on executive cognitive functions. Journal of Addiction Medicine 2011;5:1-8.

  • What happens to your body when you use marijuana?

    Within a few minutes after inhaling marijuana smoke, a person’s heart rate speeds up, the bronchial passages (the pipes that let air in and out of your lungs) relax and become enlarged, and blood vessels in the eyes expand, making the eyes look red. While these and other effects seem harmless, they can take a toll on the body.

    Short-Term Effects

    Short term effects include:

    • altered senses (such as seeing brighter colors)
    • altered sense of time
    • changes in mood
    • slow reaction time
    • problems with balance and coordination
    • increased appetite
    • trouble thinking and solving problems
    • memory problems
    • hallucinations (seeing things that aren’t really there)
    • delusions (believing something that is not true)
    • psychosis (having false thoughts)

    Mixing marijuana with alcohol can cause increased heart rate and blood pressure. It can also cause further slowing of the ability to think, solve problems, and react.

    Long-Term Effects

    • Increased heart rate. When someone uses marijuana, the heart rate (normally 70 to 80 beats per minute)—may increase or even double,   especially if other drugs are taken with the marijuana. This increases the risk of a heart attack.
    • Respiratory (lung and breathing) problems. Smoke from marijuana irritates the lungs, and can cause a chronic cough—effects similar to those from regular cigarettes. While research has not found a strong association between marijuana and lung cancer, many people who smoke marijuana also smoke cigarettes, which do cause cancer.
    • Increased risk for mental health problems. Marijuana use has been linked with depression and anxiety, as well as suicidal thoughts among teens. In addition, research suggests that smoking marijuana during the teen years might increase the risk for developing psychosis in people with a genetic risk for developing schizophrenia. Researchers are still studying the relationship between these mental health problems and marijuana use.
    • Increased risk of problems for an unborn baby. Marijuana use during pregnancy is linked to lower birth weight and increased risk of behavioral problems in babies.2

    2 The National Academies of Sciences, Engineering, and Medicine, Health and Medicine Division, Board on Population Health and Public Health Practice, Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda. The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. Washington, DC, January 12, 2017. Available at http://nationalacademies.org/hmd/Reports/2017/health-effects-of-cannabis-and-cannabinoids.aspx

  • Can you die if you use marijuana?

    There are generally no reports of people fatally overdosing (dying) on marijuana alone. However, people can feel some very uncomfortable side effects, especially when using marijuana with high THC levels. There are reports of people who use marijuana seeking treatment in emergency rooms, reporting unease and shaking, anxiety, paranoia, or hallucinations, and in rare cases, extreme psychotic reactions. Learn more about drug overdoses among youth. However, marijuana use can increase risks for accidents and injuries (impacts of drugged driving are discussed below).

  • What are the other risks associated with marijuana use?

    • Reduced school performance. Students who smoke marijuana tend to get lower grades and are more likely to drop out of high school than their peers who do not use. The effects of marijuana on attention, memory, and learning can last for days or weeks.
    • Reduced life satisfaction. Research suggests that people who use marijuana regularly for a long time are less satisfied with their lives and have more problems with friends and family compared to people who do not use marijuana.
    • Impaired driving. Marijuana affects a number of skills required for safe driving—alertness, concentration, coordination, and reaction time—so it’s not safe to drive high or to ride with someone using marijuana. Marijuana makes it hard to judge distances and react to signals and sounds on the road. High school seniors who smoke marijuana are 2 times more likely to receive a traffic ticket and 65% more likely to get into an accident than other teens.3 In 2017, 10.3% of 12th graders reported driving after using marijuana in the past two weeks.4 And combining marijuana with drinking even a small amount of alcohol greatly increases driving danger, more than either drug alone. Learn more about what happens when you mix marijuana and driving.
    Drugged Driving infographic
    • Use of other drugs. Most young people who use marijuana do not go on to use other drugs. However, those who use are more likely to use other illegal drugs. It isn’t clear why some people go on to try other drugs, but researchers have a few theories. The human brain continues to develop into the early 20s. Exposure to addictive substances, including marijuana, may cause changes to the developing brain that make other drugs more appealing. In addition, someone who uses marijuana is more likely to be in contact with people who use and sell other drugs, increasing the risk for being encouraged or tempted to try them.
    • Severe nausea and vomiting. Studies have shown that in rare cases, regular, long-term marijuana use can lead some people to have cycles of severe nausea, vomiting, and dehydration, sometimes requiring visits to the emergency room. 

    For more information on the effects of marijuana, see NIDA’s Marijuana Research Report.

    3 U.S. Department of Transportation. National Highway Traffic Safety Administration. Traffic Safety Facts. Drug Involvement of Fatally Injured Drivers. Washington, DC, November 2010. Available at: http://www-nrd.nhtsa.dot.gov/Pubs/811415.pdf.

    4 Miech RA, Schulenberg JE, Johnston LD, et al. National adolescent drug trends in 2017: Findings released [Press release]. Ann Arbor, MI. December 2017. Available at: http://www.monitoringthefuture.org/.

  • Is marijuana addictive?

    Yes, marijuana can be addictive---meaning they continue to use it despite negative consequences.

    Approximately 10 percent of people who use marijuana may develop what is called a marijuana use disorder—problems with their health, school, friendships, family or other conflicts in their life. A serious substance use disorder is commonly called an addiction. The person can’t stop using marijuana even though it gets in the way of daily life.5 People who begin using marijuana before the age of 18 are 4–7 times more likely than adults to develop a marijuana use disorder.6

    What causes one person to become addicted to marijuana while another does not depends on many factors—including their family history (genetics), the age they start using, if they also use other drugs, their family and friend relationships, and if they take part in positive activities like school, after school clubs or or sports. More research needs to be done to determine if people who use marijuana for medical reasons are at the same risk for addiction as those who use it just to get high.

    Watch the Swiss Cheese Model of Drug Addiction and learn why some people who use drugs become addicted and others do not.

    People who use marijuana may feel a mild withdrawal when they stop using the drug, but might not recognize their symptoms as drug withdrawal. These symptoms may include:

    • irritability
    • sleeplessness
    • lack of appetite, which can lead to weight loss
    • anxiety
    • drug cravings

    These effects can last for several days to a few weeks after drug use is stopped. Relapse (returning to the drug after you’ve quit) is common during this period because people may crave the drug to relieve these symptoms.

    5 Hasin DS, Saha TD, Kerridge BT, et al. Prevalence of Marijuana Use Disorders in the United States Between 2001-2002 and 2012-2013. JAMA Psychiatry. 2015;72(12):1235-1242. doi:10.1001/jamapsychiatry.2015.1858.

    6 Winters KC, Lee C-YS. Likelihood of developing an alcohol and cannabis use disorder during youth: association with recent use and age. Drug Alcohol Depend. 2008;92(1-3):239-247. doi:10.1016/j.drugalcdep.2007.08.005.

  • How many teens use marijuana?

    Marijuana is the most commonly used illicit drug in the United States by teens as well as adults. In 2009, it became more popular than smoking cigarettes but that is changing with the popularity of e-cigarettes. Recent public discussions about medical marijuana and the public debate over the drug’s legal status is leading to a reduced perception of harm among young people. In addition, some teens believe marijuana cannot be harmful because it is “natural.”7 But not all-natural plant substances are good for you—tobacco, cocaine, and heroin also come from plants. 

    In addition, marijuana vaping, along with nicotine vaping, has increased this past year. 

    Monitoring the Future 2018: Daily Marijuana Use Mostly Steady
    Monitoring the Future 2018: Teens More Likely To Use Marijuana Than Cigarettes

    Below is a chart showing the percentage of teens who say they use marijuana.

    Swipe left or right to scroll.

    Monitoring the Future Study: Trends in Prevalence of Marijuana/ Hashish for 8th Graders, 10th Graders, and 12th Graders; 2018 (in percent)*
    Drug Time Period 8th Graders 10th Graders 12th Graders
    Marijuana/ Hashish Lifetime 13.90 [32.60] [43.60]
    Past Year 10.50 [27.50] [35.90]
    Past Month 5.60 16.70 22.20
    Daily 0.70 3.40 5.80

    * Data in brackets indicate statistically significant change from the previous year.

    For more statistics on teen drug use, see NIDA’s Monitoring the Future study.

    7 Miech RA, Schulenberg JE, Johnston LD, et al. National adolescent drug trends in 2017: Findings released [Press release]. Ann Arbor, MI. December 2017. Available at: http://www.monitoringthefuture.org/.

  • What about medical marijuana?

    The marijuana plant itself has not been approved as a medicine by the federal government. However, the plant contains chemicals—called cannabinoids—that may be useful for treating a range of illnesses or symptoms. Here are some samples of cannabinoids that have been approved or are being tested as medicines:

    • THC: The cannabinoid that can make you “high”—THC—has some medicinal properties. Two laboratory-made versions of THC, nabilone and dronabinol, have been approved by the federal government to treat nausea, prevent sickness and vomiting from chemotherapy in cancer patients, and increase appetite in some patients with AIDS.
    • CBD: Another chemical in marijuana with potential therapeutic effects is called cannabidiol, or CBD. CBD doesn’t have mind-altering effects and is being studied for its possible uses as medicine. For example, CBD oil has been approved as a possible treatment for seizures in children with some severe forms of epilepsy.
    • THC and CBD:  A medication with a combination of THC and CBD is available in several countries outside the United States as a mouth spray for treating pain or the symptoms of multiple sclerosis.

    It is important to remember that smoking marijuana can have side effects, making it difficult to develop as a medicine. For example, it can harm lung health, impair judgment, and affect memory. Side effects like this might outweigh its value as a medical treatment, especially for people who are not very sick. Another problem with smoking or eating marijuana plant material is that the ingredients can vary a lot from plant to plant, so it is difficult to get an exact dose. Until a medicine can be proven safe and effective, it will not be approved by the federal government. But researchers continue to extract and test the chemicals in marijuana to create safe medicines.

    For more information, see Drug Facts—Marijuana As Medicine

    Legal Issues

    A growing number of states have legalized the marijuana plant’s use for certain medical conditions, and a smaller number have voted to legalize it for recreational use. So, in some cases, federal and state marijuana laws conflict. It is illegal to grow, buy, sell, or carry marijuana under federal law. The federal government considers marijuana a Schedule I substance—having no medicinal uses and high risk for misuse. It is important to note that because of concerns over the possible harm to the developing teen brain, non-medical marijuana use by people under age 21 is against the law in all states.

    For more information, see Drug Facts—Is Marijuana Medicine?

  • What should I do if someone I know needs help?

    If you, or a friend, are in crisis and need to speak with someone now: 

    • Call the National Suicide Prevention Lifeline at 1-800-273-TALK (they don't just talk about suicide—they cover a lot of issues and will help put you in touch with someone close by)

    If you want to help a friend, you can:

    If a friend is using drugs, you might have to step away from the friendship for a while. It is important to protect your own mental health and not put yourself in situations where drugs are being used.

    For more information on how to help a friend or loved one, visit our Have a Drug Problem, Need Help? page.

  • Where can I get more information?