Change in obsessive-compulsive symptoms mediates subsequent change in depressive symptoms during exposure and response prevention.

The current study examines the temporal relationship between changes in obsessive-compulsive symptoms and changes in depressive symptoms during exposure and response prevention (EX/RP) therapy for obsessive-compulsive disorder (OCD).,Participants were 40 adults (53% female) who received EX/RP in a randomized controlled trial comparing serotonin reuptake inhibitor (SRI) augmentation strategies. Participants completed clinician-administered assessments of OCD (Yale-Brown Obsessive Compulsive Scale) and depressive symptoms (Hamilton Depression Rating Scale) every four weeks from baseline to 32-week follow-up.,Lagged multilevel mediational analyses indicated that change in OCD symptoms accounted for 65% of subsequent change in depressive symptoms. In contrast, change in depressive symptoms only partially mediated subsequent change in OCD symptoms, accounting for 20% of the variance in outcome.,These data indicate that reductions in co-morbid depressive symptoms during EX/RP for OCD are largely driven by reductions in obsessive-compulsive symptoms.