DEFINING SUBGROUPS OF DUAL DIAGNOSIS PATIENTS FOR SERVICE PLANNING

Objective: The high proportion of persons presenting for treatment of psychiatric disorders who also have comorbid substance use problems se verely challenges the capacity of mental health care programs to plan for patients' needs. One of the problems encountered in anticipating t he treatment needs of these patients is the wide heterogeneity of thei r comorbidity, that is, the broadly varying types, severity, and time courses of psychiatric and substance disorders. This paper describes a nd evaluates a relatively simple conceptual framework for delineating the heterogeneity of patients who are dually diagnosed. Methods: A typ ology of subgroups of patients was defined a priori based on whether p atients are singly or dually diagnosed and whether their disorders are current or past. Patients admitted to three treatment facilities in a n inner-city catchment area were assigned to one of the subgroups base d on administration of the Structured Clinical Interview for DSM-III-R -Patient Version (SCID-P). The subgroups were compared on clinical dia gnoses and service needs as measured by the SCID-P and the Addiction S everity Index. Results: A total of 461 patients were assigned to four mutually exclusive dual diagnosis subgroups-patients with current defi nite dual diagnoses, current possible dual diagnoses, current substanc e-induced organic mental disorder, and past definite dual diagnoses-an d the two comparison groups. The subgroups differed significantly from each other and from two single-diagnosis comparison groups on axis I diagnoses, types of substance use disorders, and current problem areas . Conclusions: The framework developed has potential utility for disti nguishing subgroups of dually diagnosed patients relevant for service planning.