A multicenter, double‐blind, randomized, controlled study of patients with treatment‐resistant schizophrenia treated with yokukansan for 12 weeks

Abstract Aim We conducted a 12‐week double‐blind, placebo‐controlled, multicenter study to evaluate the efficacy and safety of yokukansan in patients with schizophrenia. Methods Patients with schizophrenia resistant to antipsychotics whose Positive and Negative Syndrome Scale (PANSS) scores were stable within five points were enrolled and assigned to the yokukansan or placebo group. Fifty‐three of the 61 consenting patients were allocated to the yokukansan ( n = 27) and placebo ( n = 26) groups. Results The changes in total and positive PANSS scores at 12 weeks were significantly greater in the yokukansan group than in the placebo group. There were no significant changes in other psychiatric symptom rating scores in either group. Adverse reactions were reported in six of 27 patients (22.2%) in the yokukansan group and five of 26 patients (19.2%) in the placebo group, all of which were nonserious. Conclusion Yokukansan is very safe and has clinical potential as a treatment for schizophrenia in combination with Western medicine.