Comorbidity of obsessive-compulsive disorder and depression: prevalence, symptom severity, and treatment effect

The goal of this study was to investigate the co-occurrence of depressive disorders in obsessive-compulsive disorder (OCD) and the effect of these disorders on combined pharmacologic and behavioral treatment for OCD.

A retrospective chart analysis was performed on baseline ratings of 120 OCD patients and posttreatment ratings of 72 of these patients. For depressive symptoms, the Montgomery-Asberg Depression Rating Scale and the Self-Rating Depression Scale were applied; for obsessive-compulsive symptoms, the Yale-Brown Obsessive Compulsive Scale and the Maudsley Obsessive Compulsive Inventory were used; and for general anxiety symptoms, the Self-Rating Anxiety Scale, the Clinical Anxiety Scale, and the State-Trait Anxiety Inventory were given.

One third of the OCD patients in our sample were found to be depressed. Symptom severity on OCD symptoms at baseline did not differ between depressed and nondepressed OCD patients; on general anxiety symptoms, the comorbid group was more severely affected. Both depressed and nondepressed OCD patients responded well to treatment, as reflected in assessments for depressive, obsessive-compulsive, and general anxiety symptoms. However, comorbid depression had a negative effect on treatment: depressed OCD patients showed less improvement than nondepressed OCD patients on most scales.

Depression frequently accompanies OCD and appears to affect treatment outcome negatively. While both groups of patients improved with combination treatment, the OCD-alone group had more improvement than the group that had comorbid depression.