The Tolerability of Mirtazapine Augmentation in Schizophrenic Patients Treated with Risperidone: A Preliminary Randomized Placebo-controlled Trial

OBJECTIVE: Some patients with schizophrenia may need mirtazapine augmentation to improve negative and cognitive symptoms. However there have been a few studies about the tolerability of mirtazapine augmentation to antipsychotics such as akathisia, extrapyramydal symptoms, weight gain, and body mass index (BMI). METHODS: This study was an eight-week double-blind, randomized controlled trial (RCT) of mirtazapine augmentation to risperidone. Twenty-one stabilized participants diagnosed with schizophrenia and undergoing treatment with risperidone were randomized to adjunctive treatment with mirtazapine (15 mg/day for the first two weeks, 30 mg/day for the next six weeks) or placebo. Eleven patients were assigned to the mirtazapine group, and nine patients were given placebo. RESULTS: There was no significant difference between the mirtazapine and placebo groups with respect to Barnes Akathisia rating Scale (BAS) and Sympsom-Angus Scale (SAS). However, the mirtazapine group exhibited a statistically significant increase in weight and BMI (p<0.05). CONCLUSION: These results suggest that mirtazapine augmentation can be tolerable in schizophrenic patients treated with risperidone; however, we should pay attention to the weight gain with mirtazapine. Our results should be replicated in a large-scale lengthy trial.