Differences in prescription patterns between real-world outpatients with bipolar I and II disorders in the MUSUBI survey

Objective: There is limited information available on the prescription of psychotropic agents to patients with bipolar I (BD-I) and bipolar II disorder (BD-II). The purpose of this study was to investigate the characteristics of drug therapy in BD-I and BD-II outpatients, particularly with regard to antidepressants. Methods: In 2017, the MUlticenter treatment SUrvey for BIpolar disorder in Japanese psychiatric clinics (MUSUBI) study collected data on current mental status, medications, and other factors from 2774 outpatients with BD-I or BD-II. Results: There were significant differences in the rates of prescriptions for mood stabilizers, antipsychotics and antidepressants. Mood stabilizers and antipsychotics were prescribed at higher rates to patients with BD-I (mood stabilizers; BD-I 86.0%, BD-II 80.8%, p < 0.001; antipsychotics; BD-I 61.5%, BD-II 47.8%, p < 0.001), and antidepressants were prescribed at higher rates to patients with BD-II (BD-I 32.1%, BD-II 46.4%, p < 0.001). The most commonly prescribed antidepressants were escitalopram for patients with BD-I and duloxetine for patients with BD-II. Selective serotonin reuptake inhibitors (SSRIs) were the most common class of antidepressants prescribed to patients with BD. With regard to combination therapy, combinations containing antidepressants were often prescribed to patients with BD-II. Conclusion: There was a difference in the prescription of psychotropic agents between patients with BD-I and BD-II. The outpatient prescriptions for BD in Japan were mood stabilizers and antipsychotics, which generally followed the guidelines. There is insufficient evidence regarding the effects of the prescribed antidepressants and the risk of manic episodes, and further evidence needs to be collected.