Objective: In a population of veterans with co-occurring substance use disorders and concomitant major depressive disorder, the current study compared mechanisms of change and therapeutic effects relevant to both disorders between integrated, dual disorder-specific cognitive behavioral therapy (ICBT) and twelve-step facilitation (TSF).
Method: Veterans (N = 148) were given standard pharmacotherapy for depression and were randomly assigned to receive 24 weeks of either TSF or ICBT. Process measures were selected to quantify (1) changes in self-efficacy in ICBT, (2) changes in ability to terminate negative affect in ICBT, (3) twelve-step affiliation (TSA) in TSF, and (4) changes in social support in both conditions. Measures of depression and substance use were administered to all participants before treatment, during treatment, and at the end of treatment.
Results: Self-efficacy increased among both TSF and ICBT participants during treatment, whereas self-reported ability to regulate negative affect did not change. Consistent with predictions, TSF participants increased community TSA during treatment, whereas those receiving ICBT reduced TSA. Changes in self-efficacy and TSA were associated with improvement in substance use outcomes at the end of treatment. Hypothesized changes in social support were not supported.
Conclusions: Both ICBT and TSF produce improvements in self-efficacy, and these changes are related to substance use outcomes for depressed substance abusers. In TSF, intervention-specific changes in TSA occur during the course of treatment and are related to substance use outcomes.