Older age bipolar disorder (OABD) is commonly defined as bipolar disorder in individuals aged 60 or more. General principles of pharmacotherapy in guidelines for treating OABD are greatly like those for younger adults. We aimed to investigate prescription changes among OABD patients discharged from two public mental hospitals in Taiwan from 2006 to 2019.

OABD patients discharged from the two study hospitals, from 1 January 2006 to 31 December 2019 (n = 1072), entered the analysis. Prescribed drugs at discharge, including mood stabilizers (i.e., lithium, valproate, carbamazepine, and lamotrigine), antipsychotics (i.e., second- and first-generation antipsychotics; SGAs & FGAs), and antidepressants, were investigated. Complex polypharmacy was defined as the use of 3 or more agents among the prescribed drugs. Temporal trends of each prescribing pattern were analyzed using the Cochran-Armitage Trend test.

The most commonly prescribed drugs were SGAs (72.0%), followed by valproate (48.4%) and antidepressants (21.7%). The prescription rates of SGAs, antidepressants, antidepressants without mood stabilizers, and complex polypharmacy significantly increased over time, whereas the prescription rates of mood stabilizers, lithium, FGAs, and antidepressants plus mood stabilizers significantly decreased.

Prescribing patterns changed remarkably for OABD patients over a 14- year period. The decreased use of lithium and increased use of antidepressants did not reflect bipolar treatment guidelines. Future research should examine whether such prescribing patterns are associated with adverse clinical outcomes.