1. Gateway drugs - are substances believed to open the door to the use of extremely dangerous
and powerful addictive illegal drugs such as meth, heroin, and cocaine.

2. Depressants - are drugs that inhibit the function of the central nervous system (CNS) and are
among the most widely used drugs in the world.

3. Stimulants- any drug that excites any bodily function, but more specifically those that
stimulate the brain and central nervous system.

4. Narcotics - a drug (such as opium or morphine) that in moderate doses dulls the senses,
relieves pain, and induces profound sleep but in excessive doses causes stupor, coma, or
convulsions.

5. Hallucinogens - a drug that causes hallucinations
6. Inhalants - are often among the first drugs that young teens use. In fact, they're one of the
few classes of drugs that are used more by younger teens than older ones.​