Donepezil as Add-on Treatment for Resistant Obsessive-Compulsive Disorder: Retrospective Case Series

Obsessive-compulsive disorder (OCD) is one of the most common and disabling psychiatric disorders. Treatment with serotonin selective reuptake inhibitors (SSRIs) shows significant improvement; however, residual symptoms remain in most patients despite continued adequate OCD treatment. For patients exhibiting partial or no response to multiple SSRIs, augmentation strategies are usually recommended. Here, we introduce a retrospective consecutive sample of aged patients with resistant OCD treated with donepezil augmentation to regular pharmacotherapy. Methods: Ten patients (5 males, 5 females; mean [SD] age, 63.8 [7.5] years), suffering from resistant OCD, were openly treated with donepezil 10 mg/d as add-on. Efficacy was assessed at baseline and after 8 weeks of treatment using the Yale-Brown Obsessive Compulsive Scale, Clinical Global Impression-Severity, and Clinical Global Impression-Improvement. Results: The treatment was generally well tolerated without adverse events. In all patients, mean (SD) Yale-Brown Obsessive Compulsive Scale scores diminished from 27.3 (4.3) points at baseline to 16.9 (4.5) points at week 8 (P < 0.0001). Mean (SD) Clinical Global Impression-Severity scores diminished from 5.5 (0.7) points to 3.1 (1.0) points, (P < 0.001). According to Clinical Global Impression-Improvement, 7 patients demonstrated "very much" or "much" improvement and 3 patients did not demonstrate any improvement. Conclusions: Donepezil was a well-tolerated add-on to regular pharmacotherapy in treatment-resistant OCD patients in this small cases series. Donepezil could be a promising optional therapy for patients suffering from resistant OCD, but further randomized controlled studies are necessary.