In placing the topic into a historical and systemwide context, this paper discusses the historical development of multiple systems to respond to delinquent youth, contemporary juvenile justice policy, and implications of emerging juvenile justice policy for treatment of special problem youths. Of particular concern is the changing mission of juvenile court dispositions resulting from legislation that blends punishment with treatment. The paper then reviews the scope of the problem of "special problem" youths in juvenile corrections agencies and departments. This section reviews State and program-specific findings on the prevalence of mental disorder and substance abuse within correctional facilities. A discussion of current correctional efforts to treat substance abusers examines services provided by traditional juvenile corrections institutions, special institutional substance abuse programs, alternative program models for responding to this population, and generic principles for developing approaches and programs to respond to this population. Finally, the study reviews current efforts to provide services to the mentally disordered juvenile offender. Included is an examination of several major issues that must be addressed in developing a response for this population: defining and identifying the target population, agency responsibility and roles, the use of private versus public services, general population treatment versus special facilities, and alternative programs. 6 tables, 84 references.