Background: Obsessive-compulsive disorder (OCD) is one of the most common neuropsychiatric disorders with a 60% treatment response. This trial was designed to assess the efficacy of memantine augmentation in moderate to severe OCD. Methods: This double-blinded trial was performed on 30 outpatients aged 18-60 years randomly assigned into two groups. One group received memantine with a daily dose of 5-10 mg plus 50-200mg of sertraline for eight weeks. The other group received sertraline plus a placebo for the same duration. A psychiatrist assessed patients at week 0,2,4,8 with Yale-Brown Obsessive Compulsive Scale (Y-BOCS). One-way repeated measure ANOVA was performed using IBM SPSS software. Results: Participants included 30 outpatients aged (38.30±10.66) years, 80% women. There was no significant difference between the two groups in terms of demographic data. During follow-up, the total Y-BOCS score decreased in both groups (P<0.05) without a significant between-group difference. Friedman test indicated a decrease in obsession subscale scores with no significant between-group difference (P<0.05). In the case of the compulsion subscale, there was a significant decrease in groups (P<0.05), more considerably in the memantine than in the placebo group (P<0.05). Conclusions: Memantine augmentation of sertraline has no superiority over standard treatment except for the compulsion subscale.

Obsessive-Compulsive Disorder, Memantine, Selective Serotonin Reuptake Inhibitor, Glutamate