Comorbidity of substance dependence and depression: role of life stress and self-efficacy in sustaining abstinence.

The authors examined life stress and self-efficacy as predictors of time to relapse for 113 adults with comorbid major depressive disorder and alcohol and/or substance dependence in a randomized clinical trial comparing 2 psychotherapy interventions (integrated cognitive- behavioral therapy and 12-step facilitation therapy). Life stress, self-efficacy, and substance use were assessed at treatment entry, 12 weeks (mid-treatment), and 24 weeks (end of treatment). Time to relapse was defined as the number of days from treatment initiation until first alcohol and/or drug use. Half of the sample relapsed within the study period of 24 weeks. There was no significant difference between treatment groups. Individuals experiencing life stressors were more likely to relapse early than those not experiencing life stressors. Lower self-efficacy also predicted earlier relapse. Chronic stress levels and self-efficacy were stable across time for most individuals. In contrast, acute stress events occurred at differing times, and survival analyses provided evidence of heightened relapse risk in the month following acute stressors. The interaction of self-efficacy and life stress was not significant. The results highlight the significance of life stress and self-efficacy as predictors of early relapse.