These questions were answered by more than 50 individual scientists and science writers with expertise in addiction. To get as many answered as possible, responses were written quickly based on the personal background and knowledge of each expert. Please note that there was not a secondary review or proofreading of each fact, and if readers have questions or comments about any response, they can ask further questions.

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Can marijuana cause lung cancer?

-Blue Ivy, Massachusetts

Great question Blue Ivy--unfortunately, we don't yet have an answer.  Marijuana smoke contains many of the same carcinogens and other toxins or poisons as tobacco smoke, and people tend to inhale deeply and keep the smoke in their longs for longer periods than tobacco smoke.  But studies in people have not been conclusive in showing higher rates of lung cancer in those who smoke only marijuana (and not tobacco).  Marijuana does increase the risk for other respiratory illnesses, like bronchitis, and produce increased coughing and phlegm production.

-Susan Weiss

Can marijuana change your feelings/attitude?

-yffjc, New York
Hey yffjc:  Thanks for your question!  It's a complicated question....individuals respond to drugs differently, so there's not a single answer.  In general, people take drugs for different reasons.   The bad thing is that those effects wear off and people become addicted because they have to keep taking the drug to keep the high.  Once that happens, other effects of the drugs take over and they "hijack" the brain so that you can no longer make good decisions.
Serotonin is clearly an important neurotransmitter in addiction and contributes to the intoxicating effects of alcohol--and also may be the link to alcohol and depression.  There is definitely a higher incidence of mental health issues in people who do drugs, but we don't have a good handle on why this is.  Maybe you will become a scientist and help us figure this one out!
 
You can check out this great webpage on the NIDA for teens site that explains what effect drugs have on the brain: https://teens.drugabuse.gov/drug-facts/brain-and-addiction.
-Joni Rutter

Can marijuana cure cancer?

-ashley.bowling, Kentucky

There are no studies that have shown that marihuana can cure cancer.    However the value of cannabinoids (the active ingredients in marijuana) in cancer treatment is being evaluated by researchers.

-Nora Volkow

can marijuana intoxicate drivers and cause them to be unsafe on the road?

-sampugliese, New York
Hi sampugliese,
Great question! The answer is a definite yes. Marijuana more than doubles a person's chance of being in an accident! Don't believe people who tell you they drive slower and safer when high--we've done studies on this and found that people who drive high are very impaired, and the effects on driving can be detected as much as a month (!) after using the drug. 
Be safe--don't ever use any drug and then drive, and never get in a car being driven by someone who has. 
-Eric Wargo

Can marijuana kill you?

-Angel, Texas

Hi Angel - it is often said that marijuana has never caused a death by overdose. However, there are many other harmful effects of marijuana that could increase the risk of severe injury or death.  For example, there is an increased risk of having an accident while driving under the influence of marijuana.  For more information check out https://teens.drugabuse.gov/drug-facts/marijuana.

-Steve Gust

Can medical drugs be harmful even if used properly.

-atkinsj.19, New York

Yes, in individuals that have genetic vulnerability to their adverse effects.

-Nora Volkow

can medicinal marijuana be abused, because I see many flaws in the system

-weed machine, New York
Hey weed machine,
Great question. Yes "medical marijuana" can be abused, and probably is abused. The best way to deliver marijuana's benefits to people with real health problems will be creating actual medications from the chemicals (called cannabinoids) in marijuana, such as THC and cannabidiol. Scientists are hard at work on this.
Glad you're thinking about this. 
-Eric Wargo

Can misusing prescription drugs be almost as bad as using them without a prescription?

-defaultusername, New York

yes misuse of prescription drugs  is equally dangerous if u have a prescription vs. not having one. 

-Nora Volkow

Can my body build up tolerance for drugs?

-lms611, Massachusetts
Good question.  
 
Yes, that happens with most drugs.  You take them, and over time, you need more and more to get the same effects. This happens often with individuals who have chronic pain.  It doesn't mean that they are addicted to their pain medications, though...it just means that over time their bodies have become used to the medication and at times can require higher doses to get pain relief.
-Dave Thomas

Can one drink (that has alcohal in it) effect someone who is, say 14, in a threatening way?

-aveson, California

Well, if that one drink was just a single serving, like a beer or a glass of wine, it's unlikely that a person would die but even that small amount is enough to cause small changes in balance and reaction times that could make it more likely to have an accident or get into a car crash and die. More importantly, that one drink at the age of 14 could significantly increase the risk of becoming an alcoholic later in life. Researchers found that the earlier someone has their first drink of alcohol, usually meaning more than a few sips with family, the more likely they are to become an alcoholic. It isn't known whether a few sips is enough to make that happen or if more alcohol is needed. The best bet is to avoid alcohol completely until your brain is done developing in the early 20s. You can learn more about the effects of alcohol on kids at: http://www.thecoolspot.gov/index.asp

-Aaron White

Can our skin absorb drugs

-Student6372, Maryland

Hey Student6372.  You bet our skin can absorb drugs.  For example, you can absorb drugs from "patches" like with nicotine patches, or from creams.

-Joni Rutter

can overdose of tylenol and advil have the same effects on your body as using other drugs that are known as being harmful and bad for your body and brain?

-123456, Maryland

Good morning 123456, thanks for your question!  Everyday medications like Tylenol and Advil, available over the counter, can have bad effects if people take too much or use them longer than recommended. If people take Tylenol at too high a dose or for longer than recommended, they can suffer severe liver damage. Advil can worsen asthma, for example, sometimes fatally. But Tylenol and Advil do not contain psychoactive, or 'mind-altering' ingredients, and do not produce the changes in your brain that lead to addiction. That doesn't mean that they are safe to take for long periods of time or in high doses. Also note that there are other over the counter drugs (like sleep aids) that can have surprising side effects – and need to be taken with extreme care. If you find that you need over the counter medicines frequently, make sure to consult a medical professional about how much is OK to take and what is the best medicine for your needs. Remember, if the proper amount of the drug isn't working – then it's not the right treatment for your health condition.

-Jeff Schulden

Can overdosing on trazodone cause you to be put in a concussion?

-Directioner, New Mexico

Hi Directioner...thanks for the question.  I am guessing that you are asking if overdosing can cause comas.  From what I can find, there have been reports of coma caused by trazodone.

-Joe Frascella

Can people get addicted to nicotine patches when trying to stop smoking?

-sharkesha476584, Massachusetts
Interesting question shark.
 
When people smoke they become addicted to nicotine, which makes it hard to quit smoking.  Nicotine patches can help people stop smoking because they provide the person nicotine.  When a person uses the patches to quite smoking, they usually will use patches with lower and lower amounts of nicotine until they don't need the patch anymore.  But even if they don't get off the patches, the patches are less dangerous than smoking. But you are right, they are still addicted when just using the patches.
 
Dave 
-Dave Thomas

Can withdrawal from long time drug use damage the body?

-George W. Bush, New York
Keep the questions coming, GW!  Withdrawal from alcohol and sedatives can be very dangerous, even fatal.  Withdrawal from opioids (like heroin, oxycontin) can be very uncomfortable, too.  Other substances produce uncomfortable withdrawal.  These are a major reason why people relapse. Medications can help in suppressing these withdrawal symptoms and can be a valuable first step in treatment, when combined with other therapies. 
-Wilson Compton

Can you absorb alcohol through skin?

-barackobama, New York

Yes, but not very well! 

-Aaron White

can you build a tolerance to alcohol?

-mikahakinen147, New York
Yes. Tolerance happens when the brain and the liver learn to function like normal even though a drug is in the body. So, over time, the person has to use more and more of the drug to get the desired effect. As a consequence, when the person stops the drug, their body functions in a way that is the opposite of the desired effects. This is called withdrawal. So, if a drug initially makes you feel good but you have to take more and more to get that feeling, you will likely feel really really bad when you stop. 
You can learn more about the effects of alcohol here: http://rethinkingdrinking.niaaa.nih.gov/.
-Aaron White

Can you build a tolerance to drugs or alchohol?

-official-_sean, Maryland
Hi there official-_sean.  I've gotta ask: is there an "unofficial" sean out there somewhere?  (just kidding!) Your question is important, and the answer is YES, absolutely.  For alcohol and many drugs, tolerance does build up.  That means that a person needs to take more to feel the effect. In fact, that is often when the really big problems start to happen.  A person keeps taking larger amounts of drugs or alcohol and the physical and mental damages keep growing larger!  Its always best not to start at all -- then you won't need to worry about tolerance.  Check out this website for more info: teens.drugabuse.gov
 
-Harold Perl

Can you describe rebound symptoms?

-UNIV NorthTexas, Texas

Rebound is when u have worse symptoms after the drug leaves your brain (e.g., depression even though you may have initially taken a drug to make you feel better).

-Nora Volkow

Can you die from doing a drug once?

-Kfitzy28, Massachusetts
Sure. For example, this can definitely happen with opioids like prescription pain medications. If you take too much, it can slow your breathing to the point where it just stops.  It can also happen with cocaine.  For example, a basketball player named Len Bias took cocaine for the first time, had a heart attack and died.  His entire future career was down the drain in an instant.  Now, not every person will die from taking drugs for the first time or over time, but they definitely increase their chances of having a really bad outcome each and every time they use.  Learn more about the effects of drugs on the body and how to live above the influence at - http://www.abovetheinfluence.com/?gclid=CP2oo9GWobwCFacDOgodpSAArQ  and https://teens.drugabuse.gov/drug-facts
-Dave Thomas

can you die from drinking too much caffine?

-parislover8, New York

If you have heart disease you can die from excessive caffeine consumption, but this is rare.

-Nora Volkow

can you die from excessive tylenol or any other medical drugs, without taking them with the purpose of addiction?

-asdfghjkl, Maryland

Thanks for your question.  Absolutely!  Many drugs can cause overdose and death.  Tylenol can cause liver failure.  Pain killers can cause respiratory depression.  Stimulants can cause heart attacks and strokes.  For more information on the effects of prescription and over-the-counter drugs on teens check out https://teens.drugabuse.gov/drug-facts/prescription-drugs.

-Steve Gust

can you die from hallucinogens?

-devondonahue, New York
Hey devondonahue!  It's possible.  Not common, but possible.  At high doses, blood pressure, pulse rate, and respiration drop. This may be accompanied by nausea, vomiting, blurred vision, flicking up and down of the eyes, drooling, loss of balance, and dizziness. PCP abusers are often brought to emergency rooms because of overdose or because of the drug’s severe untoward psychological effects. While intoxicated, PCP abusers may become violent or suicidal and are therefore dangerous to themselves and others. High doses of PCP can also cause seizures, coma, and death (though death more often results from accidental injury or suicide during PCP intoxication). Because PCP can also have sedative effects, interactions with other central nervous system depressants, such as alcohol and benzodiazepines, can also lead to coma.
 
I'd suggest focusing on life and pursuing natural highs like hanging with friends and having fun!  Learn more about hallucinogens using this resource - http://www.drugabuse.gov/publications/drugfacts/hallucinogens-lsd-peyote-psilocybin-pcp 
-Joni Rutter

Can you die from prescription drugs? What are the effects?

-Gem, New Jersey

Absolutely you can die from prescription drugs! The effects that the prescription drugs produce vary based on the type of drug that it is. Unfortunately, many people are taking prescription opiates now- oxycontin, hydrocodeine and others that are potent opiates. You can die by taking too much of these prescription opiates just like you could die from too much heroin. In fact, more people die from Prescription drug overdoses every year than from heroin and cocaine combined. More info on prescription drugs here: https://teens.drugabuse.gov/drug-facts/prescription-drugs

-Marilyn Huestis

can you die from smoking too much weeed. Please respond.

-BIGMAMA, New York
Hey BIGMAMA,
Good question. No, you probably won't die from weed--that's not the danger. The harms of weed have to do with affecting your brain development, especially when you're young. Studies show marijuana can permanently lower your IQ if you use it heavily as a teenager. 
You can learn more here:
-Eric Wargo

can you die from taking to much cocaine?

-Armen Kasabb, New York
Great question. Yes, you can. Cocaine can produce mental disability, very large brain ischemia (lessened blood flow to the brain), death, or give you heart attacks that lead to death.
-Anto Bonci

Can you die if you drink one cup of alcohol?

-friendlyperson1, New York

Well, if that one cup was just a single serving, like a beer or a glass of wine, it's unlikely that a person will die but even that small amount is enough to cause small changes in balance and reaction times that could make it more likely to have an accident or get into a car crash and die. If that cup was full of all vodka, then yes that might be enough to directly kill you. 

-Aaron White

can you die if you drink too much water

-RALF_WEINER, New York

hi again Ralf-weiner!  good question.  The answer is yes.  All things are toxic at a given dose--even water.  What happens is that the water depletes the electolytes in the body.  Electrolytes are what makes our heart tick, our kidney's function, our brain think, etc.  Too much water means no electrolytes and you can die.

-Joni Rutter

Can you die off of smoking alot of weed and then getting relly drunk ?

-dannyg, California

You can die by getting very drunk, whether u have marijuana or not

-Nora Volkow

can you die off of spice?

-dave, Alaska

Hi Dave- Spice is a synthetic drug that contains many different chemicals some which may be very dangerous to ingest. A number of emergency room visits were a result of spice use over the past several years. Fortunately, the word seems to have gotten out about its dangers and use is down among teens.

-Jack Stein