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

<em>Objective:</em> The Global Burden of Disease Study 2021 (GBD 2021) was employed to evaluate sex differences in the incidence of bipolar disorder (BD) and anxiety disorder (ANX) globally. <em>Method:</em> We estimated sex-specific incidence of BD and ANX from GBD 2021 globally and in 204 countries and territories from 1990 to 2021. Differences in age-standardized incidence rates (ASRs) by sex (absolute and relative) and risk ratios were calculated annually and by age. Annual Percent Change (APC) was calculated by joinpoint regression modeling and linear regression analyses were performed to explore the socioeconomic factors associated with sex differences in incidence. <em>Results:</em> The absolute and relative sex difference in ASRs of BD showed a slight declining trend during 1990 and 2021, with absolute difference decreasing from 2.50 to 1.83, and relative difference decreasing from 1.08 to 1.06; The absolute and relative sex difference in ASRs of ANX showed an increasing trend during 1990 and 2021, with absolute difference increasing from 170.02 to 208.08, and relative difference increasing from 1.35 to 1.36. Relative sex differences of BD and ANX were significantly and positively correlated with SDI (BD, standardized β = 0.27, <em>P</em> &lt; 0.001; ANX, standardized β = 0.80, <em>P</em> &lt; 0.001). <em>Conclusions:</em> Sex difference in the incidence of anxiety disorders and bipolar disorder have persisted worldwide over the past several decades, and the rates have consistently been higher among females than males. The sex difference is even more pronounced in more developed nations. Policies should pay more attention to bipolar and anxiety disorders in females.