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.