This study examines the efficacy and safety of 24 weeks memantine add-on treatment to risperidone for the treatment of negative symptomatology and cognitive impairment in patients with chronic schizophrenia. The trail was double-blind, prospective, randomized, placebo-controlled, parallel-group and consisting of a 'placebo-run-in' period, treatment, and follow-up periods. Study personnel and participants were blinded to group assignment. In the 'run-in' period, patients received Lorazepam for the treatment of anxiety and tension states for two weeks before starting antipsychotic therapy. After the 'run-in' period treatment, patients began receiving antipsychotic therapy with Risperidon with continuous concomitant administration of a 24 weeks Memantine, 20 mg/d, or placebo. Adherence was assessed at each clinic visit by pill count. In cases of anxiety and tension states, an experienced psychiatrist decided whether patients should receive Lorazepam, 5 mg/d, as rescue medication in addition to the study medication (Memantine or placebo), to which the patients remained blinded. In cases of pseudo parkinsonism patients were allowed to receive Biperiden, up to 8 mg/d, and for the treatment of patients suffering from sleep disorders Zopiclon (15 mg/d) was allowed. The consumption of alcohol and drugs were not allowed during the trial. In both study parts, psychiatric assessments were performed at baseline as well as after 2; 4; 6; 12 and 24 weeks after treatment (that is, during the follow-up period). The neuropsychological examination was performed at baseline, and after 6 and 24 weeks. Psychiatric changes, adverse events, laboratory values, dose adjustments of the antipsychotic therapy, and possible pharmacologic adverse effects were systematically monitored throughout the study.
The purpose of this study is to evaluate the efficacy and safety of 24 weeks memantine add-on treatment to risperidone for the treatment of negative symptomatology and cognitive impairment in patients with chronic schizophrenia.