Adjunctive Memantine Therapy for Cognitive Impairment in Chronic Schizophrenia: A Placebo-Controlled Pilot Study

OBJECTIVE: To investigate the effects of memantine, an N-methyl-d-aspartate (NMDA) receptor antagonist, on cognitive impairments in patients with chronic schizophrenia. METHODS: A 12-week, placebo-controlled trial was conducted to determine the effectiveness of memantine as an adjunctive treatment with conventional antipsychotic medications in 26 patients with chronic schizophrenia. The subjects were evaluated with the Korean version of the Mini-Mental State Examination (K-MMSE), the Positive and Negative Syndrome Scale (PANSS), the Hamilton Rating Scale for Depression (HAM-D), and a standard neuropsychological screening test. RESULTS: Memantine treatment was not associated with significantly improved cognitive test scores compared with the placebo control treatment. An improvement in the scores on the PANSS negative subscale was noted with memantine, but it was not significant. CONCLUSION: Adjunctive memantine treatment did not improve cognitive functioning or affect psychopathology in patients with chronic schizophrenia in the present study. Memantine, however, was tolerated well and did not exacerbate positive symptoms in patients with chronic schizophrenia.