Marijuana (pot, herb, smoke, bud or joint) is the most commonly used illegal drug in the U.S. The main active chemical is THC. Short-term effects include memory and learning problems, distorted perception, and difficulty thinking and solving problems. Derived from the same plant family, Hashish (blonde, hash, black hash) has similar effects.
In a recent study, addiction to marijuana has been shown to parallel addiction to cigarettes and alcohol. Marijuana abuse can also have other negative effects. In the study, teenagers who started abusing marijuana regularly at age 13 earned about 37 percent less at age 29 than teenagers who abstained or had light, infrequent usage.