Psychiatric prescribing patterns in patients with newly diagnosed bipolar disorder in the UK: 2000 to 2022

BACKGROUND: Bipolar disorder is an episodic mental illness, often requiring complex pharmacological management. Lithium is a first-line treatment, while antidepressant monotherapy can precipitate mania symptoms in some patients. AIMS: To (a) describe patterns of antidepressant, antipsychotic and mood stabiliser prescribing in the 12-month periods before and after first-recorded bipolar diagnosis; (b) describe treatment trajectories in the year post-diagnosis; and (c) investigate associations between sociodemographic and treatment-related characteristics of (i) antidepressant monotherapy and (ii) lithium prescription post-diagnosis. METHOD: A longitudinal cohort study of patients with a first-recorded diagnosis of bipolar disorder between 2000 and 2022 derived from Clinical Practice Research Datalink. Prescriptions for antidepressants, antipsychotics and mood stabilisers were examined in the 12 months before and after diagnosis. Logistic regression models tested associations between sociodemographic and treatment-related characteristics and prescribing outcomes. A web application (https://dop-mhds.shinyapps.io/bpd-prescribing-uk-shiny/) was developed to visualise treatment trajectories over the year following diagnosis. RESULTS: We included 40 965 patients with a first-recorded diagnosis of bipolar disorder between 2000 and 2022 (median age at diagnosis 43 years, 60.9% female, 11.1% ethnic minority). Of these, 32 460 (79.2%) were prescribed a relevant medication in the year prior to diagnosis compared with 37 208 (90.8%) in the year after. Antidepressant monotherapy was the most common pre-diagnosis treatment (48.4%), but was also prescribed to 28.9% during at least 1 month in the year after diagnosis. Antipsychotic monotherapy was the most common post-diagnosis treatment (36.0%). Lithium was prescribed to 18.5% within 1 year of diagnosis, with 4.0% receiving it as first-line monotherapy. Almost half (46.0%) switched medication at least once within 1 year. Males, ethnic minorities and patients residing in the most deprived areas had lower odds of receiving either lithium or antidepressant monotherapy. CONCLUSIONS: Prescribing patterns for bipolar disorder in the UK are highly variable and often outside of guideline recommendations, with persistent use of antidepressant monotherapy and potential under-utilisation of lithium.