Bridging the gap: Implementing BRIDGES (Brussels Resilience and Inclusion for Depression - Guidance, Exercise and Support) to shape adolescent outpatient mental health care. A pilot randomized controlled study protocol

Physical activity interventions for adolescents with depression often show limited effectiveness due to insufficient developmental tailoring, limited autonomy support, and poor contextual feasibility. BRIDGES (Brussels Resilience and Inclusion for Depression - Guidance, Exercise, and Support) is a theory-informed and co-designed physical activity intervention integrating the COM-B model, self-determination theory and motivational interviewing to support autonomous and competence-enhancing engagement. This pilot randomized controlled trial uses a hybrid type 2 implementation-effectiveness design to examine feasibility, acceptability, implementation processes and obtain preliminary estimates of clinical effectiveness to inform a future larger-scale trial.