Memantine add-on in moderate to severe obsessive-compulsive disorder: randomized double-blind placebo-controlled study.

There is a growing body of evidence for the efficacy of memantine augmentation in patients with obsessive-compulsive disorder (OCD). However, to date, no double-blind study has addressed this issue. The objective of the present randomized double-blind placebo-controlled study was to evaluate efficacy and tolerability of memantine add-on treatment in patients with moderate to severe OCD. Forty-two patients with the diagnosis of OCD based on DSM-IV-TR who had a Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score of ≥21 were randomly assigned to memantine (10 mg/day for the first week, and 20 mg/day for the rest of the trial) or placebo in addition to fluvoxamine for eight weeks. Patients were assessed using Y-BOCS every two weeks. Thirty-eight patients completed the study. Repeated measure ANOVA showed significant effect for time × treatment interaction in total scale [F (2.096, 75.470) = 5.280, P = 0.006] and obsession [F (2.340, 94.547) = 5.716, P = 0.002] and near significant effect for compulsion subscales [F (2.005, 79.179) = 2.841, P = 0.065]. By week eight, all patients in the memantine group and six (32%) patients in the placebo group [P value of Fisher's exact test <0.001] met the criteria for partial and complete response. At the end of the trial, 17 (89%) patients in the memantine group compared with six (32%) patients in the placebo group achieved remission (χ(2)(1) = 13.328, P < 0.001). Frequency of side-effects was not significantly different between the two groups. In summary, we showed that memantine add-on to fluvoxamine significantly improved short-term outcomes in patients with moderate to severe OCD.