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.