Pilot trial of ondansetron in the treatment of 8 patients with obsessive-compulsive disorder

Area of Science:

• Neuroscience
• Psychiatry
• Pharmacology

Background:

• Serotonin (5-HT) systems are linked to obsessive-compulsive disorder (OCD) symptoms.
• 5-HT3 receptor antagonists exhibit anxiolytic effects in animal models, particularly those involving risk assessment.
• OCD compulsions are often triggered by abnormal risk perception, suggesting a potential role for 5-HT3 antagonists.

Purpose of the Study:

• To investigate the efficacy of the 5-HT3 receptor antagonist ondansetron in treating OCD.
• To assess ondansetron as a potential monotherapy for OCD patients.

Main Methods:

• An 8-week open-label trial involving eight medication-free subjects diagnosed with OCD.
• Participants had a Yale-Brown Obsessive Compulsive Scale (YBOCS) score of 16 or higher.
• Ondansetron was administered at a fixed dose of 1 mg three times daily.

Main Results:

• Six subjects completed the trial, with three (37%) showing a clinically significant response (≥35% YBOCS reduction).
• Responders experienced an average YBOCS symptom reduction of 55%.
• Overall, patients showed a 28% reduction in YBOCS symptoms; the medication was well-tolerated.

Conclusions:

• Low-dose ondansetron demonstrates potential as a monotherapy for select OCD patients.
• Further research is warranted to confirm these preliminary findings.
• Ondansetron may represent a novel therapeutic avenue for OCD management.