Differential benefits of internet-based behavioral activation (iBA) for adolescents with high vs. low reward probability: a secondary analysis.

Introduction: Behavioral activation (BA) therapy is effective in treating depression in both adults and adolescents, and internet-based BA (iBA) therapy showed promise during the COVID-19 pandemic. Adolescents with depression often exhibit motivational impairment, which is associated with reduced motivation and engagement in rewarding activities as well as a heightened risk of problematic internet use. This study examined the differential benefits of iBA in alleviating depressive symptoms in adolescents with relatively high and low Reward Probability Index (RPI) levels. Methods: Using a randomized controlled trial design, this secondary analysis included 38 adolescents diagnosed with major depressive disorder, who were randomly assigned to either the iBA or internet-based psychoeducation and supportive therapy (iST) groups. Depressive symptoms, BA levels, and RPI were assessed at pre-treatment, post-treatment, and the 3-month follow-up. Results: The findings revealed that adolescents with low baseline RPI who received iBA showed a significantly greater reduction in depressive symptoms than those with high baseline RPI. Additionally, adolescents with low baseline RPI in the iBA group showed a significantly greater reduction in depressive symptoms than those in the iST group. Discussion: These results suggest that iBA is particularly beneficial for adolescents with low RPI, especially those experiencing anhedonia, and provides a promising approach to enhance treatment outcomes in this population. High accessibility of iBA may promote engagement in rewarding real-life activities.