Information from the National Institute of Drug Abuse indicates that one of every six teenagers in the United States suffers from a severe addictive problem. Marijuana is the most widely used illicit drug, and most of the initial experiences with marijuana, alcohol, and cigarettes occurs before high school. Drug use is more likely among teenagers whose mothers smoke cigarettes and/or drink alcohol moderately than among youth whose mothers abstain. Drug use is also more likely among teenagers whose older siblings use alcohol or illicit drugs and among young adults who live apart from family members. The legal, medical, traditional, and emergent models of treatment have all had little impact on the drug abuse problem. Cummings has presented a psychological model that is called exclusion therapy and that has achieved significant results. Tables and 19 references