Efficacy and cost-effectiveness of Internet-delivered cognitive-behavior therapy for children and adolescents with body dysmorphic disorder: study protocol for a randomized controlled trial.

BACKGROUND: Body dysmorphic disorder (BDD) is a prevalent and impairing mental disorder that typically onsets in adolescence. Cognitive-behavior therapy (CBT) may be effective for adolescent BDD, although the supporting evidence is currently limited. CBT for BDD is a highly specialized treatment, creating a considerable gap in access to care for young people. Therapist-guided Internet-delivered CBT (ICBT) may help bridge this gap. The primary aim of this study is to determine the efficacy of a therapist-guided ICBT program for children and adolescents with BDD versus an active comparator. Secondary aims are to examine the 6-month durability of the treatment effects and to evaluate its relative cost-effectiveness from multiple perspectives. METHODS: This is a 3-site superiority randomized controlled trial including 154 young people (12-17 years) with BDD recruited throughout Sweden. Participants are randomized 1:1 to 12 weekly modules of either therapist-supported ICBT primarily based on exposure with response prevention or an active comparator consisting of therapist-supported Internet-delivered relaxation training. Data will be collected at baseline, mid-treatment, post-treatment, and 1 month (primary endpoint), 3 months, and 6 months post-treatment. The primary outcome is BDD symptom severity measured with the Yale-Brown Obsessive-Compulsive Scale Modified for Body Dysmorphic Disorder, Adolescent version. All study personnel who can be blinded to study aims/hypotheses and group allocation will be blinded. Assessors conducting post-treatment and follow-up assessments will be external to the research team and blinded to study aims/hypotheses and group allocation at all assessment points. Analyses will be conducted according to the intention-to-treat principle and will follow a pre-specified statistical and health economic analysis plan. DISCUSSION: Participant recruitment started on 22 February 2024 and is currently ongoing. Data analysis for the primary aim will commence after the last participant reaches the primary endpoint. TRIAL REGISTRATION: ClinicalTrials.gov NCT06262412. Registered on 16 February 2024, https://clinicaltrials.gov/study/NCT06262412 .