Effect of age and sex on prescriptions for outpatients with bipolar disorder in the MUSUBI study: a cross‑sectional study.

Background: Childbearing-aged female patients and elderly patients with bipolar disorder need special attention for pharmacological treatments, but current guidelines provide little information on their pharmacological treatment. In particular, the risk/benefit balance of pharmacological treatment for childbearing-aged females with bipolar disorder is a growing concern. Therefore, we aimed to address the effect of age and sex on psychotropic drug prescription for outpatients with bipolar disorder.

Methods: The MUlticenter treatment SUrvey for BIpolar disorder in Japanese psychiatric clinics (MUSUBI) study was conducted, and data on age, sex, and details of pharmacological treatment were collected.

Results: A total of 3106 outpatients were included in this study. Among young females (age  ≤ 39), 25% were prescribed valproate. There was no significant difference in the frequency and daily dose of valproate prescription for young females among all groups. Valproate prescriptions were significantly less frequent among young males and more frequent among middle-aged males. Lithium prescriptions were significantly less frequent among young females and more frequent among older males (age  ≥ 65) and older females. Lamotrigine prescriptions were significantly more frequent among young males and young females and less frequent among older males and older females. Carbamazepine prescriptions were significantly less frequent among young males and more frequent among older males.

Conclusions: Biased information about the risk and safety of valproate and lithium for young females was suggested, and further study to correct this bias is needed. Older patients were prescribed lithium more commonly than lamotrigine. Further studies are needed to determine the actual pharmacotherapy for elderly individuals.