The influence of comorbid depression and conduct disorder on MET/CBT treatment outcome for adolescent substance use disorders

Although depression and conduct disorder frequently co-occur with substance use disorders (SUDs), few studies have investigated the individual and interactive effects of these conditions on SUD treatment outcome. Data were collected from 90 adolescents aged 13-21 (M = 17.1, SD = 2.07) who received a brief evidence-based intervention for SUD. Hierarchical regressions assessed the relationship among demographic variables, depression, conduct disorder, and two substance use outcomes (frequency and problems) at two intervals (three months, six months). Results revealed that higher baseline substance use and lower socioeconomic status significantly predicted higher substance problems and frequency at three months. At six months, higher three-month substance problems and lower depressive symptoms predicted substance problems. In addition, an interaction indicated that the effect of conduct disorder on substance problems was greatest at lower levels of depression. Results are discussed in the context of previous research indicating mixed effects of depression on SUD treatment outcome.