The design, development, and validation of a standardized assessment battery for adolescent chemical dependency is described. The battery contains scales to evaluate use motives and experiences, personal adjustment, family and peer environment, and other problems. Research into substance abuse among adolescents with attention deficit disorder and hyperactivity is reviewed including that dealing with diagnosis, risk factors, and treatment issues. A review of adult and adolescent data on client-treatment matching is presented, together with approaches for evaluating client-treatment interactions. Family-based intervention approaches are considered with respect to the theories, techniques, and empirical findings in two major paradigms: family systems and behavioral. Results of a study of the relationship between drug exploration and family management and interaction processes, peer influence, and parental drug use are provided. Also considered is the pharmacotherapeutic treatment of adolescents with schizophrenia or major affective disorders. Finally, methodological problems in treatment research and directions for future research are identified. Chapter notes, references, figures, and tables.