Six- and Twelve-Month Follow-up Results of a Cluster Randomized Controlled Trial of a CBT-Based Group Course

In the current study, we examined the durability of intervention gains over a 6- and 12-month follow-up period after the implementation of a CBT-based group intervention "Adolescent Coping with Depression Course" (ACDC) for adolescents with subclinical or mild-to-moderate depression. Data were collected from 228 youth, 133 of whom were allocated to the 14-week ACDC intervention and 95 to the usual care (UC) control condition. Analyses for the main outcome variable of depressive symptoms were performed using a random effects repeated measures piecewise growth model to estimate trajectory shape over time on an intention-to-treat basis. Results revealed that the reduction in depressive symptoms achieved during the intervention phase continued across the follow-up period for both ACDC and UC (i.e., depressive symptoms showed a significantly decreasing trend in both groups in intervention and follow-up phases); however, no differential effects between conditions were found during the follow-up phase. The direct and indirect effects of the intervention on the other outcome variables' follow-up results were also presented. ISRCTN registry ISRCTN19700389. Registered 6 October 2015. https://doi.org/10.1186/ISRCTN19700389 . Full Protocol: https://doi.org/10.1186/s12888-016-0954-y.