Metacognitive therapy versus exposure and response prevention for obsessive-compulsive disorder - A non-inferiority randomized controlled trial

Objective: Exposure with response prevention (ERP) is the first-line treatment for obsessive-compulsive disorder (OCD). However, refusals, dropouts and the required high time and logistic effort constitute barriers to the use of ERP. In a non-inferiority randomized controlled trial, we compared metacognitive therapy (MCT) to exposure with response prevention (ERP) as treatments for OCD. Method: 74 outpatients received 12 weekly sessions of either manualized MCT or ERP, with primary outcomes assessed by blinded assessors using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) at pre-treatment, midtreatment, post-treatment, and 6-month follow-up. Secondary outcomes included measures of depression and anxiety. Non-inferiority margin was specified at no less than d = 0.38 below the improvement reached by ERP, corresponding to a difference of about 3 points on the Y-BOCS. Results: Drop-out rates were low ( <14%) and similar in both groups. Linear models indicated non-inferiority of MCT to ERP at post-treatment, but not at 6-month follow-up. While both groups showed comparable Y-BOCS improvements, the MCT group demonstrated a significantly greater reduction in state anxiety scores at posttreatment and follow-up. Conclusions: Overall, MCT was not inferior to ERP, especially at post-treatment, suggesting it could be a treatment alternative. However, further research is needed to explore differential treatment indications.