A triple-blinded, randomized, placebo-controlled trial to examine the efficacy of buspirone added to typical antipsychotic drugs in patients with chronic schizophrenia

Background: The purpose of this study was to test the hypothesis that the addition of buspirone, a partial agonist of 5HT1A receptor, to ongoing treatment with typical antipsychotics would improve the positive and negative symptoms in patients with chronic schizophrenia. Materials and Methods: In this study, 50 patients including 40 male and 10 female were recruited with chronic schizophrenia who were inpatients at psychiatric teaching hospital or asylums, aged between 18 and 65 years (mean age = 47 ± 10.02). All patients were on the stable dose of typical antipsychotics for at least 1-month, and their acute symptoms were controlled. Patients were allocated in a random fashion: 25 patients to buspirone at 30 mg/day plus typical antipsychotic and 25 patients to placebo plus typical antipsychotic. The positive and negative syndrome scale (PANSS), Simpson–Angus extrapyramidal rating scale (SAS) and mini mental state examination (MMSE), were administered at baseline, and 2, 4, and 6 weeks after the addition of buspirone. Results: The 30 mg/day buspirone was well-tolerated, and no clinically important adverse effects were seen. There was no statistically significant difference between the two groups in MMSE and SAS scales. There was a significant reduction in subscales of negative, general, positive, and total of PANSS over the 6-week trial in buspirone group. There was a statistically significant difference between the two groups negative subscale (mean ± standard deviation [SD] = 14.08 ± 1.4 in buspirone group) P = 0.0219, general subscale (mean ± SD = 27.42 ± 2.1 in buspirone group) P = 0.0004, and total subscale (mean ± SD = 55.63 ± 3.9 in buspirone group) P = 0.0298, of PANSS in the 6-week of trial. Conclusion: The results suggest that adjunctive treatment with 5HT1A agonist such as buspirone may improve the negative symptoms of schizophrenia. Further studies are indicated to determine the efficacy of 5HT1A agonist treatment in chronic schizophrenia.