Evaluation of Memantine effect as adjunctive therapy in patients with treatment-resistant obsessive-compulsive disorder (double-blind, controlled clinical trial)

Introduction: Despite proven efficacy ofserotonin reuptake inhibitors (SRIs) in the treatment of obsessive–compulsive disorder (OCD), refractoryOCD is still a therapeutic challenge. There is a large body of evidence on the clinical benefits of augmentation therapy with glutamate-modulating agents such as memantine in reducing OCDsymptoms. The aim of the present study was to assess the efficacy ofmemantine augmentation in SRI-refractory OCD patients.
Materials and methods: A double-blind, randomized, placebo controlled trial was conducted onSRI-refractory OCD patients who had failed at least 3 SRI trials. 32 patients, stable on an existing SRI for a minimum of 3 months were recruited and received either 20mg/daymemantine or placebo augmentation for 12 weeks. Patients were visited at baseline and then every four weeks and results were measured using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS).
Results: Y-BOCS total scores weresignificantly reduced in the memantine group at the end of weeks 8 and 12, while no improvement was observed in the placebo group throughout the trial. A reduction of 40.9% in the mean Y-BOCS total score by week 12 in the memantine group resulted in 100% of patients achieving treatment response.The findings showed that a time to effect of 8 weeks was necessary to observe significant improvement in OCD symptoms, while treatment response was only seen after 12 weeks of memantine augmentation.
Conclusions: High dose memantinecan be an effective and well-tolerated augmentation in severe OCD patientsrefractory toSRI monotherapy.
Keywords: Obsessive-compulsive disorder, Serotonin reuptake inhibitors,N-methyl-D-aspartate antagonist,glutamate receptor,memantine, treatment refractory.