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, mid-treatment, 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 post-treatment 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.