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Research Summary

Computer versus Therapist-delivered Treatment for Co-occurring Depression and Alcohol/ Cannabis Use

When depression and substance abuse occur together, as is common, either condition can hamper effective treatment of the other. Behavioral interventions that address both conditions have not been rigorously tested. Although delivering such interventions by computer holds promise for extending their reach, their effectiveness in treating these co-occurring disorders 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 the treatment of depression and comorbid alcohol and/or cannabis use. After a single baseline brief-intervention session, 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.

  • Although the initial treatment session demonstrated modest efficacy for depression as well as alcohol and/or cannabis use, outcomes across all 3 conditions were further improved among MI/CBT recipients.
  • The proportion of participants with improved depressive symptoms (Beck Depression Inventory score, <17) and with diminished alcohol and/or cannabis use (<50% as many hazardous use days per month) at 12 months did not differ significantly among recipients of therapist- or computer-delivered interventions.


These data provide clear evidence that combining interventions to target depression as well as alcohol and/or cannabis use can improve outcomes in both conditions, and that delivering such interventions by computer may be effective and reduce costs associated with therapist time. The results might have been less favorable had intent-to- treat analyses assumed that participants lost to follow-up had resumed drug use. In addition, the intensity of the intervention (10 hour-long sessions) raises questions about feasibility in typical practice settings. As computer-delivered interventions gain acceptance, further studies to define cost-effectiveness and completion rates outside of research settings are warranted. Marc N. Gourevitch, MD, MPH


Kay-Lambkin FJ, Baker AL, Lewin TJ, et al. Computer- based psychological treatment for comorbid depression and problematic alcohol and/or cannabis use: a randomized controlled trial of clinical efficacy. Addiction. 2009; 104(3):378–388.