Bipolar disorder prevalence and psychotropic medication utilisation in Hong Kong and the United Kingdom

Purpose Bipolar disorder (BPD) is often an under‐addressed mental disorder. Limited studies have investigated its epidemiology and drug utilisation in Hong Kong (HK) and the United Kingdom (UK) and thus local prescribing practices remain unclear. This study aimed to determine the prevalence of BPD and the prescribing of psychotropic medications as maintenance treatment from 2001–2018 in HK and the UK. Method A retrospective study using the data from Clinical Data Analysis and Reporting System in HK and IQVIA Medical Research Data in the UK. Results The prevalence of BPD diagnosis in HK and the UK more than doubled during the study period. Some distinct changes in prescribing patterns over time were observed. Lithium use declined by 2.46% and 14.58% in HK and the UK, respectively. By 2018, patients were 4.6 times more likely to receive antidepressant monotherapy in the UK versus HK (15.62% vs. 3.42%). In HK, 38.41% of women of childbearing age were prescribed valproate in 2018 compared with 8.46% in the UK. Conclusion The prevalence of BPD diagnosis has been increasing in HK and the UK. The disparity in prescribing patterns of BPD maintenance treatment in two regions reflected three major issues in clinical practice: (1) under‐prescribing of lithium in both regions, (2) antidepressant monotherapy in the UK and (3) overprescribing of valproate to women of childbearing age in HK. A review of current clinical treatment guidelines and regulations of prescribing practice by local clinicians should be immediately implemented to ensure the safe use of medications in patients with BPD.