Augmentation of antipsychotic treatment with memantine in patients with schizophrenia: A systematic review and meta-analysis

Abstract

Many patients with schizophrenia respond partially to treatment with antipsychotic medications. A wide range of pharmaceutical agents are utilized as augmentation therapy in order to increase the efficacy of antipsychotic medication treatment. Memantine, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist is one of these add-on agents. In this study we aimed to assess the efficacy of memantine augmentation by conducting a systematic review and meta-analysis on the psychopathology of patients with schizophrenia receving antipsychotic medication. Method: We analyzed the double-blind, randomized, placebo-controlled trials of memantine add-on treatment given to schizophrenia patients receiving antipsychotic medications. The primary outcome measure was amelioration of negative symptoms and the secondary outcome measures were amelioration of positive, total and general psycopathology symptoms. Publication bias was evaluated by the Funnel plot and Egger test. Results: Eleven studies on a total of 570 cases were included. Although memantine add-on treatment was superior to placebo for ameliorating negative symptoms (SMD=0.596, 95% CI=0.075-1.118, p=0.025), there were not any statistically significant differences in the amelioration of general psycopathology (SMD=0.034, 95% CI=0.419-0.488, p=0.883), the positive (SMD=-0.041, 95% CI=0.217-0.135, p=0.650) and the overall symptoms. (SMD=0.315, 95% CI=0.256-0.887, p=0.280). Publication bias was not observed between studies according to the results of the Funnel plots and Egger tests. Conclusion: Memantine augmentation treatment is beneficial for treating particularly the negative symptoms of schizophrenia patients. Further studies on the subject with larger sample size and longer follow-up durations are needed.