In challenging these myths, this booklet provides empirical data to show that marijuana can cause short-term memory loss, distorted perception, irrational thinking and problem solving, and anxiety, thus jeopardizing school performance and positive social development. It is also associated with later use of other illicit drugs and drug dependence. The earlier adolescents start using marijuana, the more likely they are to become dependent on it or other illicit drugs. Regular use of marijuana apparently is at least as damaging to the users' health as regular use of tobacco, and adolescents who use marijuana weekly are nearly four times more likely than nonusers to report engaging in violent behavior. Legitimate health claims have been made for THC, the primary active chemical in marijuana, but it is available in prescription medicine; as a smoked product, marijuana has never proven to be medically beneficial. Marijuana has been the most widely used illicit drug among high school seniors for decades. Further, marijuana contributes to behaviors that harm others, including the user's children. Parents can effectively intervene to prevent their children from experimenting with marijuana. Although its use is illegal, the response of the criminal justice system is to provide treatment and prevention measures for users, not imprisonment. 83 references