NIDA for Teens: The Science Behind Drug Abuse
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Word of the Day: Addiction

Addiction is defined as “A chronic, relapsing disease characterized by compulsive drug seeking and use—despite serious, even devastating consequences—and by long-lasting chemical changes in the brain.” When a person is addicted to a drug, finding and using that drug becomes the most important thing—more important than family, friends, school, sports, or money.

Not everyone will become addicted after they smoke a cigarette, drink alcohol, or take another drug, but even experimenting can raise your risk.

Have you heard about all these celebrities going in and out of rehab? That’s because addiction is a chronic, relapsing disease, like heart disease, hypertension, or diabetes that can be managed with treatment. And even though a person may beat their addiction with treatment, he or she is always at risk of relapse.

If you think you or a friend may be addicted to a substance, talk to a family member, medical professional, or other trusted adult to get help. You can also check out the Substance Abuse and Mental Health Services Administration’s Treatment Facility Locator for treatment services near you.

To learn more about addiction, check out NIDA’s publication, Drugs, Brains, and Behavior: The Science of Addiction.


Word of the Day: Relapse

Relapse…If you keep up with the SBB you know by now that addiction is a chronic (long-lasting) disease that takes hold in some people who abuse drugs. You may also know that some people can quit their drug use. But often a person will return to using drugs after they have quit. This is what NIDA Scientists call a relapse.

Why does it happen? Addiction changes the wiring of the brain to cause uncontrollable craving and compulsive drug use—despite the consequences. For someone with an addiction, going without the drug for periods of time can make that person feel so anxious and stressed that they need the drug just to stop feeling bad.

A person who is addicted to a drug usually needs professional treatment to quit drug use. This can include medication or "talk therapy (PDF, 1.19 MB)," or a combination of both. It also helps to have support in the family and the community. While quitting drug use is possible, addiction is a long-lasting disease, and treating it takes time-and just because someone gets treatment and stops using a drug does not mean that these strong cravings go away for good, especially when certain cues are present. These cues vary from person to person and can trigger a relapse.

Imagine that your best friend is addicted to cigarettes and says she smokes to relieve stress, but that she recently quit because her boyfriend hates the smell of cigarette smoke. Since she has connected cigarette smoking with stress relief, the next time your friend faces a stressful situation, like a fight with parents or final exams, she will most likely crave a cigarette, increasing her risk of a relapse. Her use of cigarettes, which led to an addiction to nicotine, has also caused her to associate "relaxation" with cigarettes.

Not everyone will relapse once they have quit drug use; it depends on the person, their genes, their environment, and many other factors, including personal commitment and family support.

For more information on addiction and today's "Word of the Day," check out the myths about drug abuse or the Brain and Addiction page on the NIDA for Teens website.

Girl with hand on face

Word of the Day: Polyneuropathy

According to NIDA’s glossary, polyneuropathy is a “permanent change or malfunction of nerves.” “Poly” means “many,” so multiple nerves throughout the body such as in the arms, legs, hands, and feet are affected.

Possible symptoms of polyneuropathy are weakness, the feeling of pins and needles, or burning pain. In the most extreme cases, people can have trouble breathing and experience organ failure.

Many things can cause polyneuropathy, from genetics to a nutritional deficiency. But something else can also cause it—inhaling toxic, poisonous fumes, like those found in certain household products, in order to get high.

Long-term inhalant abuse can break down myelin, a fatty tissue that surrounds and protects some nerve fibers. Myelin helps nerve fibers carry their messages quickly and efficiently throughout the body and to the brain. Damaged myelin can lead to muscle spasms and tremors or even permanent difficulty with basic actions like walking, bending, and talking.

Don’t forget about sudden sniffing death, which can occur when inhaled fumes fill up the cells in the lungs with poisonous chemicals, leaving no room for the oxygen needed to breathe. This lack of oxygen can lead to nerve damage, suffocation, and even death.

Sudden sniffing death could occur during a person’s 100th time using inhalants or the first time. There’s no way to predict it.

Learn more about the consequences of abusing inhalants.

Brain cells firing.

Word of the Day: Disease

What's the first thing that comes to mind when you hear the word disease? You might think of cancer, diabetes, or epilepsy. But do you think of drug abuse? Probably not. But, for some people, drug abuse can lead to a disease called addiction.

A disease is when something in the body doesn't work like it's supposed to-an organ or a whole system has something wrong with it and disrupts functioning. Diseases can be caused by many different factors, from your genes (what you inherited from your parents) to germs and viruses to not getting the vitamins that your body needs to stay healthy.

Some diseases can be cured with medication or changes in lifestyle and may never come back. Others are chronic diseases, meaning they last for a long time or can come back again.

Addiction is a chronic disease. Drugs change the way the brain works, and using them can lead to addiction. Once a person is addicted to a drug, they feel the need to take that drug over and over just to feel like their "normal" self. Tracking down and taking the drug usually becomes more important than eating, sleeping, dating, doing school work, or earning money.

Even if they stop using drugs, people with addiction have brains that have been chemically altered, making them vulnerable to relapse (resuming drug use).

To learn more, take a look at The Science of Addiction. Share something you didn't know before.

This picture is showing us an inside view of the brain from the top down. It compares healthy brain activity (left side, with all the red areas) with diminished brain activity in a drug user (right side).

Word of the Day: Serotonin

Have you ever noticed all the different emotions you experience in a normal day? For example, you can feel happy in the morning when you find out you passed your bio quiz, grumpy at noon when you haven’t eaten since breakfast, and then sad when the football team loses the big Homecoming game.

Chemicals called neurotransmitters, which carry messages across the gaps between neurons in your brain, influence your changing mood. One neurotransmitter, dopamine, increases alertness and makes you feel happy when something good happens. Lots of abused drugs raise a person’s level of dopamine.

Serotonin, another neurotransmitter, affects the brain in a different way. Known as the “calming chemical,” serotonin eases tension and stress. It lifts a person’s mood, lessens anxiety and aggression, promotes sleep, and also affects appetite, memory, and perceptions.

“It’s a molecule involved in helping people cope with adversity … to keep going and try to sort everything out,” says Philip J. Cowen, a serotonin expert at Oxford University and the Medical Research Council. To quote his Manchester University colleague Bill Deakin, “It’s the ‘Don’t panic yet’ neurotransmitter.”

Serotonin also puts a brake on the excitement and sometimes recklessness that dopamine can produce. When the overall brain chemical system is working well, it seems that these chemicals interact to balance out extreme behaviors. That’s why it can lead to problems when a person takes illegal drugs that affect serotonin or dopamine.

Many different drugs affect serotonin levels in complex ways. For example, when a person uses MDMA (Ecstasy or “Molly”), serotonin increases in different parts of the brain, causing elevated mood and feelings of empathy. Some studies show that elevated serotonin from illegal drug use plays a role in the person wanting to take more of the drug, possibly leading to addiction.

For more information on how drugs affect brain chemicals, check out NIDA’s article, Impacts of Drugs on Neurotransmission.

The serotonin neuron showing serotonin and serotonin receptors.

Word of the Day: Euphoria

Euphoria: A feeling of well-being or elation.

Euphoria is that excitement you get from getting a perfect score on a test, or attention from someone you have a crush on. It can come from a roller coaster ride or as the rush from a physical activity like downhill skiing, especially the first time. These feelings of euphoria are all healthy and natural.

What's not healthy or natural is taking drugs to feel "euphoric." Drugs of abuse artificially produce euphoria by manipulating your brain chemistry to make it seem that something exciting is happening. To get this feeling again, you may choose to use the drugs again-and again. And that can lead to craving and addiction.

Over time, the brain needs more of the drug to get the same feelings of pleasure. Why? The drug causes surges, like waves, of the brain chemical dopamine, which initially produce the euphoria. After repeated hits, though, the brain adjusts to this higher level of dopamine by making less of it and by reducing the number of receptors that can receive and transmit the signals it sends. Pretty soon, the drug abuser is taking the drug just to bring the dopamine functions back up to normal and to avoid the horrible craving that compels them to seek and use drugs even when their lives and health are falling apart. That is really the essence of addiction.

People jumping in the air.

But the good news is that natural, healthy experiences of euphoria don't wreck the brain's chemistry. So think about what you do in life that makes you feel good. Spending time with friends, playing with your dog, doing sports, seeing a good movie? Any of these activities can create a natural euphoria by triggering the brain's reward system the way it was meant to work.

So don't let drugs fool your brain, and then wreck it.

image of Euphoria

Word of the Day: Neuroscience

Your school probably has science classes like biology and chemistry and maybe even ecology, but does it offer a class specifically on neuroscience?

Neuroscience is a branch of biology that focuses on the body’s nervous system—which includes the spinal cord, nerves, neurons (nerve cells) and, of course, the all-important brain.

Work in the neuroscience field is varied and exciting. Neuroscientists might study how messages travel from one area of the brain to the other, or they might focus on how the brain is involved in behavior and decision-making.

Still others might work to find causes of and cures for diseases and medical problems like stroke, Parkinson’s disease, depression, Alzheimer’s disease, schizophrenia, and addiction.

At NIDA, research focuses heavily on neuroscience, considering that drug addiction is a brain disease. Without neuroscientists and the research they do, we would be unaware of some pretty important things—like how the brain isn’t fully developed until a person is well into their 20s and how drugs like marijuana affect the teen brain differently than an adult brain.

So much about the brain is still unknown. That makes neuroscience a particularly exciting field. If you are interested in help shed light on the mysteries of the brain, consider exploring neuroscience as a career. Check out the advice NIDA scientists offered to SBB for teens interested in a future career in science.

Learn more about the brain from these NIDA resources:


Hands holding a glowing brain

Word of the Day: Axon

You may remember hearing something about neurons in biology, but what about today’s word of the day: axon?

Neurons are nerve cells in the brain that communicate with each other 24/7 to control everything we do, think, and feel. The axon is the long, tunnel-like part of the neuron (see picture) that steers messages from the cell to other nerve cells or body tissues, such as muscles.

Since the axon’s only job is to transmit messages from point A to point B, it can focus on doing it fast. For this reason, many axons are lined with a fatty material called myelin, which helps the message glide through the axon quickly. Prolonged drug use can damage the axon or the myelin, causing noticeable changes in a person’s behavior over time.

For example, scientists have discovered that abusing certain drugs on a long-term basis—like inhaling fumes or markers—can eat away at myelin. Without its protective myelin lining, the axon itself is more vulnerable to harm. An axon that is damaged or is missing myelin cannot transmit messages as well to other nerve cells, if at all. For someone with damaged axons, this can mean muscle spasms, tremors or difficulty with basic motor skills, like walking, bending, or talking.

More info is available on the NIDA for Teens’ Web site about axons and their role in the brain’s communication system, as well as inhalants and their effects on the body.

Picture of an axon

Comorbidity, a Word for Thought...

“Comorbidity” is a strange word, right? Well, at least for me it was. I have to admit it that it was the first scientific word I learned during my internship here at the National Institute on Drug Abuse (NIDA)–my Spanish accent still gives me a hard time pronouncing it. On the first day of my internship, I had to read and get acquainted with the extensive research that NIDA has done and published. Comorbidity was featured in NIDA’s Research Report Series.

So, what’s co-mor-bid-it-y? Here’s what NIDA scientists say: “When two disorders or illnesses occur in the same person, together or one after the other, they are called comorbid.” Having two disorders together can also cause them to interact in ways that make both of them worse.

So what does all of that really mean? It means that sometimes two illnesses go together. For example, people who have depression or other mental illness are often addicted to drugs as well, and vice versa, so that’s why scientists say depression is often “comorbid with” drug abuse.

NIDA scientists aren’t completely sure why people who are depressed are more likely to have a drug abuse problem. But here’s my take on it. Everyone has felt down before. If someone feels really bad, they may turn to drugs to “ease their mind.”  Unfortunately, that can lead to a second disease–addiction to drugs–and then they feel even worse than they did before.

That’s what’s really bad about comorbid diseases: they can make each other worse! If someone is depressed, it’s harder to be motivated to quit using drugs. And if someone is using drugs, it can interfere with their treatment for depression.

What other diseases do you think could be comorbid? And why?

This is a guest SBB post from NIDA intern Giselle.

image of a stressed brain

Word of the Day: Psychoactive Drugs

Have you ever heard the term ”psychoactive drugs?” Drugs in this category act on the central nervous system and and alter its normal, everyday activity, causing changes in mood, awareness, and behavior. Psychoactive drugs disrupt the communication between neurons (brain cells), so abusing them can have serious short- and long-term effects on the brain.

Psychoactive drugs include four groups of drugs: depressants like alcohol and sleeping pills; stimulants like nicotine and ecstasy; opioids like heroin and pain medications; and hallucinogens like LSD.

The term psychoactive drug might make you think of drugs, like LSD, that change your brain and behavior in really extreme ways. LSD is a hallucinogen, or “psychedelic” that significantly alters the brain and the user’s perception of reality. It is also an illicit, or illegal, drug.

But not all psychoactive drugs are illegal. Caffeine is a stimulant found in coffee and energy drinks, and opioids like Vicodin, OxyContin, or morphine are often prescribed by doctors to relieve pain. Abusing prescribed psychoactive drugs is illegal though, and can be as dangerous as abusing cocaine or heroin. That is one reason why they come with warning labels telling people not to drive or operate heavy machinery. Drinking too much caffeine is not good for you either (see chart)!

So legal or illegal, psychoactive drugs demand caution.

NIDA provides lots of information about the different types of psychoactive drugs:

Warning Sign

Word of the Day: Brainstem

Our bodies can do lots of things without us even thinking about it. And that’s what the Word of the Day is about. The brainstem, not surprisingly, is a “stem” that connects the brain to the spinal cord. Its basic functions include directing heart rate, breathing, arousal, and sleeping. Lucky for us, the brainstem does all these things automatically. That’s why you don’t forget to breathe when you’re asleep!

How? The brainstem directs the spinal cord, other parts of the brain, and the body to do what is necessary to maintain our life.

The brainstem is one of the more primitive parts of our brain—it dates back to the age of the dinosaurs! Just like another primitive part of our brain, the limbic system.

One of the reasons that addictive drugs exert such powerful control over our behavior is that they act directly on our primitive brainstem and limbic system.

For more brainy words, check out the NIDA for Teens glossary that fuels SBB’s words of the day.

A diagram of the brain anatomy, highlighting the location of the brainstem. The brainstem is located between the brain and the spinal cord.

Word of the Day: Depressants

What’s the first thing you think of when you hear the word “depressants?” Maybe “depressed” or “sad?” But the drugs called depressants aren’t called that because they’re depressing in the emotional sense.

Depressants slow down (or “depress”) the normal activity that goes on in the brain. Alcohol is a depressant.

Doctors often prescribe central nervous system (CNS) depressants to patients who are anxious or can’t sleep. When used as directed, CNS depressants are safe and helpful for people who need them.

Types of CNS Depressants

CNS depressants can be divided into three main groups:

  • Barbiturates, which are used to treat some forms of epilepsy
  • Benzodiazepines (Valium, Xanax), which can be used to treat severe stress, panic attacks, convulsions, and sleep disorders
  • Sleep medications (Ambien, Sonata, Lunesta), which, as the name suggests, are used to help people with diagnosed sleep problems

How They Work

Most CNS depressants affect the brain in the same way—they enhance the activity of the gamma-aminobutyric acid (GABA). GABA is a neurotransmitter, one of the naturally occurring chemicals in the brain that sends messages between cells. GABA works by slowing down brain activity.

Although different classes of CNS depressants work in unique ways, they ultimately increase GABA activity, which produces a drowsy or calming effect.

Effects When Abused

CNS depressants can be addictive* and should be used only as prescribed. Otherwise, they can bring about major health problems, including addiction. Combining them with alcohol or other drugs like pain medications can lead to slowed breathing and heart rate, and even death.

Find out more about depressants from this NIDA fact sheet (PDF, 718kb).

(*Addiction is when a person compulsively seeks out the drug and cannot control their need for it, even in the face of negative consequences.)

Young man sleeping on homework

Word of the Day: Cerebral Cortex

What do walnuts and our Word of the Day have in common?

Well, it’s a stretch, but fun to think about. If you crack open a walnut carefully, you can see it has two “sides”—just like the human brain. And that’s where our “word of the day” comes in.

The cerebral cortex covers most of the other brain parts inside your head—making up two-thirds of the brain’s mass. No surprise, since the cerebral cortex is what allows us to speak and understand, learn languages, play music, and a lot more.

Like a walnut, the cerebral cortex has two sides called “hemispheres.” The left hemisphere rules things like our ability to talk, write, and learn languages. The right hemisphere rules our musical abilities, and how we figure out distances and other “spatial” challenges. For example, does it look like you and all your friends can fit into that diner booth? Oops, not quite.

And that’s not all. Our sense of touch also uses both hemispheres of our brain! Walnuts anyone?

For more brainy words and others, check out NIDA’s glossary.

girl crunching a walnut with a bowl of walnuts below her

Word of the Day: Limbic System

NIDA’s Glossary defines the limbic system as “a set of brain structures that generates our feelings, emotions, and motivations. It is also important in learning and memory.”

The limbic system, known informally as the “center for emotions,” is made up of five parts that help ensure our survival, including the ability to feel emotion, long-term memory storage, memory retrieval, and other behaviors directly connected with the emotions.

Each part has a separate role that makes the system run smoothly.

1) Amygdala—a tiny, almond-shaped structure commonly associated with processing emotions like anger, fear, and pleasure.

2) Cingulate Gyrus—a structure that receives messages from other parts of the brain and is essential in higher thinking functions, respiratory control, and memory, and learning.

3) Fornix—a tough, arch-shaped band that connects the two lobes of the cerebrum (the large rounded structure that makes up most of the brain and is divided into two hemispheres).

4) Hippocampus—a brain structure that is key to memory storage and retrieval; damage to it often means significant long-term memory loss.

5) Hypothalamus—a brain structure that regulates involuntary or automatic responses, including body temperature and food digestion. Drugs disrupt the feelings and motivations that form the basis of normal behavior. A person abusing drugs is artificially feeling pleasure by interfering with the limbic system.

Various crazy, cartoon faces.

Word of the Day: Dopamine

Imagine this: You're playing basketball; it's the last quarter. In fact, you only have 30 seconds to make the winning shot. You shoot, it soars through the air, you hear the buzzer go off...and then you see the swoosh.

You just won the game for your team. How do you feel?

The answer to that question involves a chemical in your brain, called dopamineour word of the day. Dopamine delivers important messages between neurons (brain cells). That's why it's called a "neurotransmitter." Dopamine is an especially important neurotransmitter, because it helps to control movement, motivation, emotions, and sensations like pleasure.

Back to the basketball game. After you made that winning basket, dopamine sent "messages" to your neurons to help you feel happy, pumped, and overjoyed that you made that winning shot. Dopamine would also be working away in your teammates' brains as they ran out onto the court to celebrate, and in the brains of the cheering fans jumping up and down in the stands.

But it doesn't stop there. Dopamine is at work all the time, delivering messages to neurons and motivating you to participate in the more basic activities of life, like eating foods you like or spending time with family and friends. How dopamine works in the brain is especially important in teens since teens' brains are still developing. When dopamine levels are affected by drugs like cocaine, it can affect the brain's "wiring," causing important messages to get lost in translation. Messing with dopamine can affect your motivation to go to prom or ability to make that winning basketball shot,—even your ability to feel happiness. And that's why drugs might cost you more than just the basketball game.

For more in-depth resources and other brainy words, check out NIDA's interactive glossary that fuels my "Words of the Day."

Basketball going through basketball hoop.

Word of the Day: Brain Reward System

A reward is a great way to encourage someone to do something. For example, if you offer a $300 reward to find your lost dog, people may be more likely to look for and return him or her. Or, if your parents offer to reward you for keeping your room clean or getting good grades, you have an incentive to do it. Our brain has its own reward system. When we do certain things, the brain rewards us by making us feel good. The brain reward system is a brain circuit that causes feelings of pleasure when it is “turned on” by something we enjoy (see figure), like eating good food or being in love.

Whenever this reward circuit is activated, our brains note that something important is happening that is worth remembering and repeating. Drugs activate the brain reward system in a similar manner. However, most drugs set off a surge of the brain chemical dopamine and therefore produce a much stronger and longer-lasting “artificial” pleasure sensation than natural highs. The effect of such a powerful reward strongly motivates people to take drugs again and again, even when they no longer really want to. That can happen because drugs can actually reprogram the brain, so that every time a person takes the drug, the effect is a little weaker, and so they have to take more and more of it to get the same feeling. Eventually, a person can become addicted to the drug and compulsively use it, not so much to feel good but to keep from feeling bad. That’s the “sneaky” part of addiction. NIDA provides lots of information about the how drug abuse targets the brain’s pleasure center:

Word of the Day: "AIDS"

AIDS stands for acquired immunodeficiency syndrome. It’s a disease caused by the HIV virus, which breaks down the body’s immune system, or our natural defenses against disease. Without our immune system, our bodies cannot fight off illness.

HIV used to be thought of as a disease that happened only to injection drug users and gay men. That is not true. In fact, according to a recent report from the Centers for Disease Control, heterosexual contact between men and women accounted for the second biggest chunk (31%) of all new HIV infections in 2006—more than twice the rate of infections among intravenous drug users. And guess which age group had the most new HIV infections? Young people ages 13-29. In particular, adolescents who have unprotected sex are putting themselves at increased risk of getting HIV.

NIDA research backs this up. It shows that teens like Kim and her friends who drink or use drugs may be putting themselves at a higher risk for contracting HIV, because being high or drunk can lead to having risky sex. To learn more about the link between HIV/AIDS and drug abuse, check out NIDA’s Learn the Link campaign, and get to know the facts on how our decisions, however small they may seem, can majorly affect our health.

girl with her hand on her forehead showing she is upset and sad

Word of the Day: Withdrawal

Ever wonder how “real” those grueling scenes on reality TV shows are when actors and other celebrities check in for addiction rehab and are shown going through withdrawal? After all, these folks are all in show biz!

SBB was curious about exactly how withdrawal happens. Withdrawal is defined as: symptoms that occur after chronic use of a drug is reduced or stopped.

But that’s just where the story begins. The symptoms of withdrawal vary a lot by drug, including how harsh they are and how long they last.

Consider prescription opioids, or painkillers. These are drugs like oxycodone (better known as Oxycontin) or hydrocodone (Vicodin). Opioids are typically prescribed for someone having severe pain, from the ache after a root canal to a chronic condition like back pain from an injury. When opioids are taken as prescribed, they can provide temporary relief from severe pain. But, they are also highly addictive and must be taken only as prescribed.

Some people will abuse a prescription drug by taking more than prescribed, or in ways not intended, which can lead to serious problems, including slowed heartrate and breathing and even addiction. And just like with “illegal” drugs, quitting is hard and can bring on withdrawal symptoms. Opioid withdrawal symptoms can include restlessness, muscle and bone pain, insomnia, diarrhea, vomiting, cold flashes with goose bumps ("cold turkey"), and involuntary leg movements. Yikes.

Taking away the chemicals that alter your brain through drugs of addiction is a pretty harsh reality. Your body and brain react strongly, even violently sometimes, because of missing the chemicals they’ve come to depend on through repeated drug use.

If a person knew from the start that quitting drugs would be so difficult, would they think twice before trying them? Probably so… Know the facts.

Eye of person in withdrawl

Word of the Day: Cerebellum

Our word for today is: Cerebellum

Cerebellum: A portion of the brain that helps regulate posture, balance, and coordination during activities such as playing ball, picking up objects, and balancing.

Why do I like this word so much? Say it again: "cer·e·bel·lum" (s?r'?-b?l'?m)—yup, it's my namesake! When we walk down the street or concentrate on keeping our balance, our cerebellum is guiding us. The cerebellum coordinates our voluntary muscle movement as well as our posture and balance, like a puppeteer helping us put one leg in front of the other. Suppose you're playing ball? Picking up your pet? Playing a musical instrument? Your cerebellum is hard at work inside your head so you can slam dunk that basketball, hold onto the cat, and play each note on your electric guitar perfectly. And these are just a few of the activities that the cerebellum handles for us. The cerebellum is located just above the brainstem, where our brain connects to our spinal cord. The average teen's cerebellum weighs about 6 ounces. That's about one-eighth of the total weight of our brain, which weighs about 3 pounds. Hmm...who knew something so little could be so powerful? You can look up more words in the NIDA for Teens glossary.

a girl balancing on beam