When depression and substance abuse occur together, either condition can hamper effective treatment of the other. Behavioral interventions that address both conditions at once have not been rigorously tested. Although delivering such interventions by computer holds promise for extending their reach, the effectiveness of this approach remains unknown. In a randomized trial, researchers measured the effectiveness of an intervention combining principles of motivational interviewing (MI) and cognitive behavioral therapy (CBT) in treating both depression and comorbid alcohol and/or cannabis use. After a single baseline brief intervention (BI), 97 persons with co-occurring depression and heavy alcohol and/or cannabis use were randomized to receive either no further treatment (n=30) or nine 1-hour sessions of MI/CBT treatment delivered either by a therapist (n=35) or by computer (n=32). Sixty-seven patients completed the study. Depression and alcohol/cannabis use were assessed at 3, 6, and 12 months following treatment completion.

• The MI/CBT conditions were more effective for lowering depression symptoms than BI at 12 months.
• Therapist-delivered MI/CBT was more effective for depression than computer-delivered MI/CBT at 3 months, but there was no difference in results at 12 months.
• Problematic alcohol consumption was reduced in all 3 conditions, with best results observed in the therapist-delivered MI/CBT condition.
• The MI/CBT conditions were more effective than BI in reducing cannabis and hazardous-substance use, with best results observed in the computer-delivered MI/CBT condition.
• Computer-delivered MI/CBT saved 79% of therapists' time compared with face-to-face MI/CBT treatment.

Comments by Michael G. Boyle, MA
These results support the development of clinical algorithms that are population-based and provide stages of treatment. For example, BI for alcohol use disorders may be the first intervention, followed by more intensive ongoing treatment if the desired results are not obtained. Addiction treatment is very labor intensive with 75% of its costs related to staffing. Computerized interventions are a means of increasing access to treatment while potentially lowering costs per episode of care. The combination of computerized interventions with brief therapist contact is particularly well-suited for federally qualified health centers, which receive an enhanced rate for brief treatment encounters.