Bouldering-Psychotherapy for treating depression in adolescents (BooSt): study protocol for a randomized controlled trial

Abstract Background Currently, there are hardly any validated group therapy programs for depressed adolescents in Germany. A recent meta-analysis confirmed a moderate antidepressant effect of exercise in adolescents with depressive symptoms. In addition, four recent systematic reviews reported positive effects of exercise interventions on psychological well-being, mood, and quality of life in adolescents with depression or depressive symptoms. We developed a manualized behavioral-therapy-based group program involving Bouldering-Psychotherapy (BPT) for adolescents (BPT-J) based on the adult version of BPT, which has already demonstrated its efficacy. The aim of the study is to evaluate the efficacy of BPT-J. Methods The study is designed as a randomized, controlled, prospective, longitudinal, single-blind trial with two arms (BPT-J intervention group [IG], waitlist-control group [CG]). The primary aim is to investigate the efficacy of the BPT-J group therapy for adolescents for treating depressiveness. Eligible participants are adolescents with subclinical and clinical depressive symptoms between 13 and 18 years of age. The adolescents in the CG are offered participation in an identical intervention after t1. The 10-week intervention is accompanied by four data collection points for all participants: participants and their legal guardians fill out online questionnaires at the start of therapy (t0), immediately after IG therapy (t1), after CG therapy (t2), and 12 months after finalizing the intervention (follow-up, t3). In addition, structured video interviews are conducted at t0 and t1. Discussion BooSt trial addresses the limited availability of evidence-based group interventions for adolescents with depressive symptoms in routine care. If efficacy is confirmed, BPT-J may represent a scalable, manualized, and potentially well-accepted treatment approach that could complement existing psychotherapeutic services for adolescents. Given the increasing demand and limited access to psychotherapy, the intervention may contribute to improving accessibility of mental health care. The group-based format may additionally support cost-effective implementation, reduce waiting times, facilitate peer support, and help reduce stigmatization associated with mental health treatment. Findings from the BooSt trial may further inform dissemination and implementation strategies in child and adolescent mental health care. Trial registration ISRCTN, ISRCTN79659949, prospectively registered 19/02/2025, DOI: https://doi.org/10.1186/ISRCTN79659949 , URL: https://www.isrctn.com/ISRCTN79659949 .