Abstract
Background: Medications currently recommended for the treatment of Obsessive-Compulsive Disorder (OCD) usually relieve the severity of symptoms by as much as 20–30%, and satisfactory treatment is obtained in 40–60% of patients with OCD. Nevertheless, the remaining symptoms continue to impair the patients’ function. Therefore, it is necessary to investigate possible strategies to improve the mitigation of symptoms.In this study, the main objective was to examine and investigate the effectiveness of granisetron, which is a serotonin 5-hydroxytryptamine receptor type 3 (5-HT3) antagonist, as an adjunct therapy to selective serotonin reuptake inhibitors, for the purpose of ameliorating OCD symptoms. Methods: fifty-eight patients diagnosed with OCD, based on Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, who had a Yale-Brown obsessive-compulsive scale (Y-BOCS) score of more than 21 were recruited in a double-blinded, parallel-group, placebo-controlled, clinical trial of 10 weeks to receive either granisetron (1 mg twice daily) and sertraline (100 mg daily initially followed by 200 mg daily after week 4) or placebo and sertraline. The primary outcome was OCD symptoms measured by the Y-BOCS.Results: Y-BOCS total score significantly dropped in both groups (28.9 to 17.7 for granisetron and 27.5 to 19.3 for placebo group with a slightly greater drop for granisetron group), while the granisetron group experienced a significantly greater reduction in obsession scores (Greenhouse-Geisser F(2.32,97.57)=4.52,p-value=0.01). Moreover, in comparison with the placebo group, the proportion of the patients showing complete response was considerably higher among the granisetron group (P-value <0.01). No major adverse effects were observed in any of the groups. Conclusion: The results suggest that granisetron augmentation of sertraline may increase the rate of response in patients with moderate to severe non-refractory OCD. Further studies are suggested in this regard.Trial registration: The trial was registered at the Iranian Registry of Clinical Trials on 27/03/2019 (www.irct.ir; IRCT ID: IRCT20170123032145N3).