Behavioural Activation for Young people (BAY): a study protocol for a randomised controlled trial investigating the clinical effectiveness, cost effectiveness and acceptability of behavioural activation for young people in CAMHS settings

Background: Emotional disorders in young people have been increasing, leading to a high demand for support and long waiting times for UK child and adolescent mental health services (CAMHS). Consequently, access to evidence-based psychological therapy is limited; in addition, many young people do not respond to existing treatments. Blended delivery of therapy, which combines face-to-face and digital interventions, offers a promising solution to improve the reach and effectiveness of mental health support. However, the efficacy of blended behavioural activation (BA) for young people with depression is not yet established. Methods: This randomised controlled trial will investigate the clinical and cost effectiveness of blended behavioural activation intervention for adolescents aged 11-17 years with moderate to severe depression. We will recruit 446 participants from CAMHS across 6 sites in the UK. Participants will be randomised to receive either BA with psychoeducation (PE) and treatment as usual (TAU) or PE and TAU. The primary outcome measure will be depressive symptoms, assessed using the child-completed Mood and Feelings Questionnaire (MFQ-C) at 6 months. A range of secondary outcome measures will be collected to estimate the clinical and cost effectiveness and acceptability of the intervention. A nested qualitative investigation exploring provider and young people/carer perspectives will be included. Discussion: The findings from this trial will provide crucial evidence on the effectiveness of blended BA for young people with moderate to severe depression. If effective, this intervention could offer a scalable and accessible treatment option, potentially transforming the delivery of mental health services for adolescents. The large sample size and pragmatic approach will enhance the generalisability of the results, informing future clinical practice and policy. Trial registration: ISCRTN12315118