Alcohol, tobacco and drugs (narcotics) are all types of drugs. They are called drugs because they are toxic and because people who use them become intoxicated and may become addicted.
We are affected in different ways by alcohol and other drugs, but drugs affect everyone in the short or long term.
They affect those who use them, but also those around the users. When you're young, the risk of physical damage is greater. For example, the brain continues to develop throughout your teenage years.
If you're worried that someone is using drugs, you shouldn't keep your thought to yourself. Tell the person him- or herself, or someone you trust, that you can see the problem. If you think that you've become addicted and need help to quit, it can be a good idea to speak to a friend or adult.
On the right are links to more information about alcohol, drugs and tobacco.