This report reviews the impact of substance abuse and mental health problems among the adolescent population, examines the research issues and treatment delivery system, identifies model modalities and programs to address the needs of adolescents, and makes practical recommendations on the implementation of effective treatment methods for youths. The first part of the report examines the epidemiological evidence regarding the prevalence and incidence of substance abuse and mental illness in adolescents, and outlines the categories of programs in the drug and alcohol and mental health systems. The second part describes 12 adolescent treatment programs, selected for their unusual or innovative approaches. The report concludes with general recommendations for the replication of innovative programs; the recommendations target project design, staff training and development, and work with families. (42 references) (JDD)