Adequate periods of abstinence should be achieved before the patient is re-examined for residual symptoms compatible with a nonaddictive, non-substance-induced psychiatric disorder. The integration of concurrent treatment of both mental and addictive disorders appears to be the best approach. An abstinence-based model that typically uses 12-step group therapy is often employed for addictive illnesses. Other forms of psychosocial therapies, such as case management, are being used as well. Prescribing practices of physicians for comorbid addicted patients are currently based on traditional approaches to the use of medications in psychiatric patients, and attitudes of physicians toward addictive disorders may play a significant role in determining overall treatment success. Treatment considerations for specific disorders are noted, including unipolar depression, bipolar, anxiety-related, psychotic, and schizophrenic disorders. 61 references and 3 figures