TREATMENT TRIAL AND LONG-TERM FOLLOW-UP EVALUATION AMONG COMORBID YOUTH WITH MAJOR DEPRESSION AND A CANNABIS USE DISORDER.

Objective: This study compared the acute phase (12-week) and the long-term (1 year) efficacy of fluoxetine versus placebo for the treatment of the depressive symptoms and the cannabis use of youth with comorbid major depressive disorder (MDD) and an cannabis use disorder (CUD)(cannabis dependence or cannabis abuse). We hypothesized that fluoxetine would demonstrate efficacy in the acute phase trial and at the 1-year follow-up evaluation. Data is also provided regarding the prevalence of risky sexual behaviors in our study sample.

Methods: We recently completed the first double-blind placebo-controlled study of fluoxetine in adolescents and young adults with comorbid MDD/CUD. A total of 70 persons participated in the acute phase trial, and 68 of those persons (97%) also participated in the 1-year follow-up evaluation. Results of the acute phase study have already been presented (Cornelius, Bukstein, et al., 2010), but the results of the 1 year follow-up assessment have not been published previously. All participants in both treatment groups also received manual-based cognitive behavioral therapy (CBT) and motivation enhancement therapy (MET) during the 12-week course of the study. The 1-year follow-up evaluation was conducted to assess whether the clinical improvements noted during the acute phase trial persisted long term.

Results: During the acute phase trial, subjects in both the fluoxetine group and the placebo group showed significant within-group improvement in depressive symptoms and in cannabis-related symptoms. However, no significant difference was noted between the floxetine group and the placebo group on any treatment outcome variable during the acute phase trial. End of study levels of depressive symptoms were low in both the fluoxetine group and the placebo group. Most of the clinical improvements in depressive symptoms and for cannabis-related symptoms persisted at the 1-year follow-up evaluation.

Conclusions: Fluoxetine did not demonstrate greater efficacy than placebo for treating either the depressive symptoms or the cannabis-related symptoms of our study sample during the acute phase study or at the 1-year follow-up assessment. The lack of a significant treatment effect for fluoxetine may at least in part reflect efficacy of the CBT/MET psychotherapy. A persistence of the efficacy of the acute phase treatment was noted at the 1-year follow-up evaluation, suggesting long-term effectiveness for the CBT/MET psychotherapy.