Sex differences in the incidence of bipolar and anxiety disorders: Findings from the Global Burden of Disease Study 2021

Objective: The Global Burden of Disease Study 2021 (GBD 2021) was used to assess sex differences in the global incidence of bipolar disorder (BD) and anxiety disorders (ANXs). Methods: We estimated sex-specific incidence rates of BD and ANXs from GBD 2021 for 204 countries and territories from 1990 to 2021. Annual and age-specific differences in age-standardized incidence rates (ASRs) by sex (absolute and relative), along with risk ratios, were calculated. Annual percent change was determined using joinpoint regression modeling, and linear regression was used to examine socioeconomic factors associated with sex differences in incidence. Results: Between 1990 and 2021, the absolute sex difference in ASRs for BD declined from 2.50 to 1.83, and the relative difference decreased from 1.08 to 1.06. In contrast, the absolute sex difference in ASRs for ANXs rose from 170.02 to 208.08, and the relative difference increased from 1.35 to 1.36. Relative sex differences in BD and ANXs were significantly positively associated with the sociodemographic index (BD, standardized β = 0.27, P < 0.001; ANXs, standardized β = 0.80, P < 0.001). Conclusion: Sex differences in the incidence of BD and ANXs have persisted worldwide over recent decades, with consistently higher rates among females relative to males. These sex differences are more pronounced in higher-income countries and territories. Policies should place greater emphasis on addressing BD and ANXs among females.