Drugs are chemicals that change the way a person's body works. You've probably heard that drugs are bad for you, but what does that mean and why are they bad?

Medicines Are Legal Drugs

If you've ever been sick and had to take medicine, you already know about one kind of drugs. Medicines are legal drugs, meaning doctors are allowed to prescribe them for patients, stores can sell them, and people are allowed to buy them. But it's not legal, or safe, for people to use these medicines any way they want or to buy them from people who are selling them illegally.

Cigarettes and Alcohol

Cigarettes and alcohol are two other kinds of legal drugs. (In the United States, adults 18 and older can buy cigarettes and those 21 and older can buy alcohol.) But smoking and excessive drinking are not healthy for adults and are off limits for kids.

Illegal Drugs

When people talk about a "drug problem," they usually mean abusing legal drugs or using illegal drugs, such as marijuana, ecstasy, cocaine, LSD, crystal meth, and heroin. (Marijuana is generally an illegal drug, but some states allow doctors to recommend it to adults for certain illnesses.)

Why Are Illegal Drugs Dangerous?

Illegal drugs aren't good for anyone, but they are particularly bad for a kid or teen whose body is still growing. Illegal drugs can damage the brain, heart, and other important organs. Cocaine, for instance, can cause a heart attack — even in a kid or teen.

While using drugs, people are also less able to do well in school, sports, and other activities. It's often harder to think clearly and make good decisions. People can do dumb or dangerous things that could hurt them — or other people — when they use drugs.

Why Do People Use Illegal Drugs?

Sometimes kids and teens try drugs to fit in with a group of friends. Or they might be curious or just bored. Someone may use illegal drugs for many reasons, but often because they help the person escape from reality for a while. A drug might — temporarily — make someone who is sad or upset feel better or forget about problems. But this escape lasts only until the drug wears off.

Drugs don't solve problems, of course. And using drugs often causes other problems on top of the problems the person had in the first place. Somebody who uses drugs can become dependent on them, or addicted. This means that the person's body becomes so accustomed to having this drug that he or she can't function well without it.

Once someone is addicted, it's very hard to stop taking drugs. Stopping can cause withdrawal symptoms, such as vomiting (throwing up), sweating, and tremors (shaking). These sick feelings continue until the person's body gets adjusted to being drug free again.

Can I Tell If Someone Is Using Drugs?

If someone is using drugs, you might notice changes in how the person looks or acts. Here are some of those signs, but it's important to remember that depression or another problem could be causing these changes. Somebody using drugs might:

• lose interest in school
• change friends (to hang out with kids who use drugs)
• become moody, negative, cranky, or worried all the time
• ask to be left alone a lot
• have trouble concentrating
• sleep a lot (maybe even in class)
• get in fights
• have red or puffy eyes
• lose or gain weight
• cough a lot
• have a runny nose all of the time

What Can I Do to Help?

If you think someone is using drugs, the best thing to do is to tell an adult that you trust. This could be a parent, other relative, teacher, coach, or school counselor. The person might need professional help to stop using drugs. A grownup can help the person find the treatment needed to stop using drugs. Another way kids can help kids is by choosing not to try or use drugs. It's a good way for friends to stick together.

Words to Know

Understanding drugs and why they are dangerous is another good step for a kid to take. Here are some words that may be new to you:

Addiction (say: uh-dik-shun) — Someone has an addiction when he or she becomes dependent on or craves a drug all of the time.

Depressant (say: dih-preh-sunt) — A depressant is a drug that slows a person down. Doctors prescribe depressants to help people be less angry, anxious, or tense. Depressants relax muscles and make people feel sleepy, less stressed out, or like their head is stuffed. Some people may use these drugs illegally to slow themselves down and help bring on sleep — especially after using various kinds of stimulants. (See below.)

Hallucinogen (say: huh-loo-sun-uh-jun) — A hallucinogen is a drug, such as LSD, that changes a person's mood and makes him or her see or hear things that aren't really there or think strange thoughts.

High — A high is the feeling that drug users want to get when they take drugs. There are many types of highs, including a very happy or spacey feeling or a feeling that someone has special powers, such as the ability to fly or to see into the future.

Inhalant (say: in-hay-lunt) — An inhalant, such as glue or gasoline, is sniffed or "huffed" to give the user an immediate rush. Inhalants produce a quick feeling of being drunk — followed by sleepiness, staggering, dizziness, and confusion.

Narcotic (say: nar-kah-tik) — A narcotic dulls the body's senses (leaving a person less aware and alert and feeling carefree) and relieves pain. Narcotics can cause someone to sleep, fall into a stupor, have convulsions, and even slip into a coma. Certain narcotics — such as codeine — are legal if given by doctors to treat pain. Heroin is an illegal narcotic because it is has dangerous side effects and is very addictive.

Stimulant (say: stim-yuh-lunt) — A stimulant speeds up the body and brain. Stimulants, such as methamphetamines and cocaine, have the opposite effect of depressants. Usually, stimulants make someone feel high and energized. When the effects of a stimulant wear off, the person will feel tired or sick.

Reviewed by: Mary L. Gavin, MD
Date reviewed: May 2010
Originally reviewed by: Ryan L. Redman, MD