The general downward trend in drug use by high school seniors has continued since 1979, but 1985 was the exception when this downward trend tapered off. Another exception was the increase in use of cocaine, which reached a record high in 1985 before significantly declining in 1987. Very little is known about the state of the art of the treatment of chemically dependent adolescents. Development and implementation of successful treatments require determination of a successful treatment outcome, whether certain forms of treatment modalities are superior to others, what types of patients do better on these treatment modalities, the necessity of treating adolescents differently than adults, and how to improve the quality of treatment already provided. Prevention of drug use and abuse among children and adolescents can be performed on two levels. Primary prevention is intended to prevent the occurrence of drug use; secondary prevention aims to detect the problem in its early stages of development. 2 figures, 54 references.