1. To conduct a multi-site RCT to determine the efficacy of "dual focus" 12-step mutual aid groups for persons with co-occurring substance use and mental disorders. Substance-using patients who are admitted to psychiatric outpatient clinics will be randomly assigned within each clinic to (i) DTR group participation plus standard treatment, or (ii) standard treatment as usual (wait list for DTR). The primary outcome is drug/alcohol use. The secondary outcomes are psychiatric medication adherence; quality of life; treatment retention; and traditional 12 step group participation. Major assessments will occur at baseline and 6 months later.