Clinical Implications of the Co-Occurrence of Substance Use and Other Psychiatric Disorders

The co-occurrence of substance use and psychiatric disorders is the rule rather than the exception in mental health and substance use treatment settings across the United States. Such co-occurrence may call for special assessment and evaluation procedures, modified treatment plans, and specialized follow-up. Treatment of co-occurrence of substance abuse and psychiatric disorders requires more cross-disciplinary collaboration; greater integration of substance use, mental health, and social ser-vices treatment approaches; and modifications in the training of care providers. Only approximately 20 % of all psychiatric conditions exist in their pure form; almost 80 % exist in tandem with at least one other psychiatric disorder (Kessler, 1995). Much of the co-occurrence of disorders is accounted for by the co-occurrence of substance abuse or dependence disorder and another psychiatric disorder. The great frequency of, and the special needs presented by, such co-occurrence may have profound implications for the assessment and treatment of individuals presenting with these problems. This article provides an epidemiological overview of this phenomenon and the clinical implications of such co-occurrence for practicing psychologists. Epidemiological Overview Coexistence rates for psychiatric and substance use disorders have been reported to range from 25 % to 58 % (Alexander