This report highlights the important trends in adolescent drug use. Although the focus is on the abuse of alcohol, nicotine, marijuana, cocaine, heroin, and inhalants, it is important to remember that adolescents abuse a wide range and combination of drugs. This report also addresses state-of-the-art treatment methods, and summarizes research on risk factors and prevention efforts conducted over the past decade. The information on trends and treatment outcomes provides the critical information needed to direct new strategies for decreasing adolescent drug use in the 21st century. (Contains 13 figures and 49 references.) (ADT)