Pilot Trial of Ondansetron in the Treatment of 8 Patients With Obsessive-Compulsive Disorder

Method: Eight medication-free subjects with a DSM-IV diagnosis of OCD and a Yale-Brown Obsessive Compulsive Scale (YBOCS) score >= 16 entered an 8-week open-label trial of ondansetron at a fixed dose of 1 mg 3 times daily in a study conducted between February and October 1998.

Results: Six subjects completed the trial. Three subjects (37%) achieved a clinically significant response (>= 35% reduction in YBOCS score). For these subjects, the average reduction in YBOCS-rated symptoms was 55%. In aggregate, the 8 patients exhibited a 28% reduction in YBOCS-rated symptoms over the course of the trial. The medication was well tolerated.

Conclusion: These results suggest that low-dose ondansetron may have promise as a monotherapy for some patients suffering from OCD.