Ethnic disparities in time to bipolar disorder diagnosis: retrospective cohort study.

Lithium is a first-line maintenance treatment for bipolar disorder yet delays in diagnosis and lithium initiation remain common. This retrospective cohort study examined whether time to bipolar disorder diagnosis and lithium initiation differ by ethnicity, gender or age among 88 patients at South London and Maudsley National Health Service Foundation Trust. Delay outcomes were non-normally distributed and log-transformed before analysis. No demographic characteristic was significantly associated with time to lithium initiation. Ethnicity was significantly associated with diagnostic delay, with individuals from minority ethnic groups experiencing longer delays than White individuals (median 556 v. 50.5 days; IQR [89.8, 1342] v. [6.25, 222]), which persisted after adjustment for age, gender, substance use and illness severity, and remained robust to outlier removal. Although social deprivation was not accounted for, these findings suggest possible systematic diagnostic inequities in bipolar disorder, calling for culturally informed diagnostic practices and further investigation in larger, multi-site samples.