A drug is a chemical substance that can change how your body and mind work. Drugs of abuse are substances that people use to get high and change how they feel. They may be illegal drugs like pot, cocaine, or heroin. Or they may be legal for adults only, like alcohol and tobacco.

Medicines that treat illness can also become drugs of abuse when people take them to get high—not because they're sick and following their doctor's orders. People can even abuse cough or cold medicines from the store if they ignore the directions and take too much at one time.

People abuse drugs for many reasons:

  • They want to feel good. Taking a drug can feel really good for a short time. That's why people keep taking them—to have those good feelings again and again. But even though someone may take more and more of a drug, the good feelings don't last. Soon the person is taking the drug just to keep from feeling bad.
  • They want to stop feeling bad. Some people who feel very worried, afraid, or sad abuse drugs to try to stop feeling so awful. This doesn't really help their problems and can lead to addiction, which can make them feel much worse.
  • They want to do well in school or at work. Some people who want to get good grades, get a better job, or earn more money might think drugs will give them more energy, keep them awake, or make them think faster. But it usually doesn't work, may put their health at risk, and may lead to addiction.