The impact of depression on abstinence self-efficacy and substance use outcomes among emerging adults in residential treatment.

A large proportion of emerging adults treated for substance use disorder (SUD) present with symptoms of negative affect and major depressive disorder (MDD). However, little is known regarding how these comorbidities influence important mechanisms of treatment response, such as increases in abstinence self-efficacy (ASE). This study tested the degree to which MDD and/or depressive symptoms interacted with during-treatment changes in ASE and examined these variables' relation to outcome at 3 months' posttreatment. Participants (N = 302; 74% male) completed measures at intake, midtreatment, end-of-treatment, and at 3-month follow-up. ASE was measured with the Alcohol and Drug Use Self-Efficacy (ADUSE) scale; depressive symptoms were assessed with the Brief Symptom Inventory 18 (BSI 18) Depression scale; and current MDD diagnoses were deduced from the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Random coefficient regression analyses focused on during-treatment changes in ASE, with BSI 18 scores and MDD diagnosis included as moderators. At intake, individuals with MDD or high levels of depressive symptoms had significantly lower ASE, particularly in negative affect situations. No evidence for moderation was found: ASE significantly increased during treatment regardless of MDD status. There was a main effect of BSI 18 Depression scores: those with lower BSI 18 scores had lower ASE scores at each time point. MDD and BSI 18 Depression did not predict 3-month outcome, but similar to previous findings ASE did predict abstinence status at 3 months. Treatment-seeking emerging adults with MDD merit particular clinical attention because of their lower reported self-efficacy throughout treatment.