Say Smoking No Forever

Marijuana is the most commonly used illegal drug among youths and adults and is used by an estimated 75 percent of all illegal drug users. An estimated 4 million youths in the United States (16 percent of all youths), ages 12–17, reported using marijuana in the past year.

The key psychoactive ingredient in marijuana is a chemical called tetrahydrocannabinol (THC), which is the ingredient responsible for its intoxicating effects. THC is most appropriately described as a hallucinogen.