Prescribing changes for bipolar patients discharged from two public psychiatric hospitals in Taiwan, 2006-2019

Background: For bipolar disorder, a severe, recurring mental disorder, pharmacotherapy is a cornerstone of effective treatment. The purpose of this study was to investigate prescribing changes among patients with bipolar disorder discharged from two public psychiatric hospitals in Taiwan over a 14-year period. Methods: Patients with bipolar disorder discharged from the two study hospitals between 2006 and 2019 (n = 9071) were included in the analysis. Prescribed drugs for the treatment of bipolar disorder, including mood stabilizers (i.e., lithium, valproate, carbamazepine, and lamotrigine), any antipsychotics (i.e., second- and firstgeneration antipsychotics; SGAs & FGAs), and any antidepressants, were examined. 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. Results: The prescription rates of SGAs, any antidepressants, antidepressant monotherapy, antidepressants without mood stabilizers, and complex polypharmacy significantly increased over time, whereas the prescription rates of any mood stabilizers, lithium, carbamazepine, FGAs, and antidepressants plus mood stabilizers significantly decreased. Limitations: Treatment allocation is not randomized in a retrospective study. The diagnoses of bipolar disorder were based on clinical judgments. This was a hospital-based study. Conclusions: Substantial prescribing changes took place during the study period. The decreased use of lithium and the increased use of antidepressants were not in accordance with the evidence-based treatment and recommendations in treatment guidelines. Therefore, long-term outcomes of prescribing changes should be explored in the future.