A Double-Blind, Randomized, and Placebo-Controlled Trial of Buspirone Added to Risperidone in Patients With Chronic Schizophrenia

Objective: The role of partial agonism at 5-HT(1A) receptors in general and of buspirone in particular remains unclear in the treatment of negative symptoms of schizophrenia. This study was designed to investigate the effect of buspirone added to risperidone as augmentation therapy in patients with chronic schizophrenia and prominent negative symptoms in a double-blind randomized clinical trial. Methods: The participants were 31 men and 15 women aged 19 to 44 years who were inpatients at 2 psychiatric teaching hospitals in Iran. All patients were inpatients and were in the active phase of the illness and met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for schizophrenia. Patients were allocated in a random fashion: 23 patients to risperidone at 6 mg/d plus buspirone at 60 mg/d and 20 patients to risperidone at 6 mg/d plus placebo. The outcome was measured using the Positive and Negative Syndrome Scale. Results: The buspirone group had significantly greater improvement in the negative symptoms and positive general psychopathology subscales and Positive and Negative Syndrome Scale total scores over the 8-week trial. Therapy with 60 mg of buspirone per day was well tolerated, and no clinically important adverse effects were observed. Conclusions: The present study indicates buspirone as a potential adjunctive treatment strategy for the treatment of schizophrenia, in particular, negative symptoms. Nevertheless, results of larger controlled trials are needed before recommendation for a broad clinical application can be made. This trial is registered with the Iranian Clinical Trials Registry (IRCT138712051556N8).