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

Lithium is a first-line maintenance treatment for bipolar disorder (BD) yet delays in diagnosis and lithium initiation remain common. This retrospective cohort study examined whether time to BD diagnosis and lithium initiation differ by ethnicity, gender, or age among 88 patients at South London and Maudsley (SLaM) NHS 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 substantially longer delays than White individuals (median 556 vs 50.5 days; IQR [89.8, 1342] vs [6.25, 222]). This effect persisted after adjustment for age, gender, substance use, and markers of illness severity, and remained robust to outlier removal. Although the study could not account for social deprivation, these findings suggest possible systematic diagnostic inequities in BD, highlighting the need for culturally informed diagnostic practices and further investigation in larger, multi-site samples.