Topiramate augmentation in refractory obsessive- compulsive disorder: A Randomized, Double-Blind, Placebo-controlled trial

This study aimed to assess the effectiveness of Topiramate, a glutamate-modulating agent, in patients with treatment-resistant obsessive-compulsive disorder (OCD) as an adjunct to serotonin reuptake inhibitors (SRIs). Thirty-eight patients with refractory OCD, were randomly assigned to receive Topiramate or placebo. This study was designed as a 12-week, double-blind, placebo-controlled trial. Primary outcome measures were the change in Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score and the rate of treatment response in each group at the study end point. Treatment response was considered as 25% or more reduction in Y-BOCS score. 13 patients in the Topiramate group and 14 ones in the placebo group completed the trial. Topiramate-assigned patients showed significantly improved mean Y-BOCS score over time (p<0.001). Although differences between two groups was significant in the Y-BOCS score at the first two months (p=0.01), this was not significant at the end of study (p=0.10). Changes of Clinical Global Impression (CGI)-Severity of Illness scale score and CGI-Improvement scale score were not significantly different between two groups (p>0.05).Treatment response was almost significantly different in the Topiramate group comparing placebo group (p=0.054). Mean Topiramate dosage was 137.5 mg/day (range, 100-200). This study didn’t show effectiveness of Topiramate as an agent to augment SRIs in treatment-resistant OCD patients.