Background:　Bipolar　disorder　is　a　chronic　psychiatric　condition　characterised　by　recurrent　episodes　of　mania　and　depression.　Methods:　Our　study　analyzed　the　data　from　the　Global　Burden　of　Disease　(GBD)　study,　covering　the　years　1990　to　2021.　This　dataset　includes　key　metrics　such　as　incidence,　prevalence,　disability-adjusted　life　years　(DALYs),　years　lived　with　disability　(YLDs),　and　age-standardized　rates.　By　utilizing　the　Socio-demographic　Index　(SDI)　quintiles　and　the　XGBoost　model,　we　sought　to　assess　and　predict　the　long-term　impact　of　regional　economic　disparities　and　sociodemographic　factors　on　the　burden　of　bipolar　disorder.　Results:　Our　study　indicates　that　the　global　incidence　of　bipolar　disorder　has　been　steadily　increasing,　rising　significantly　from　30,239,332　cases　in　1990　to　53,917,371　cases　in　2021.　This　increase　predominantly　affects　women　and　adolescent　populations.　Moreover,　a　significant　positive　correlation　exists　between　the　burden　of　bipolar　disorder　and　the　SDI.　Developed　countries　generally　show　higher　age-standardized　incidence　rates,　age-standardized　mortality　rates,　and　age-standardized　DALY　rates　than　developing　countries.　However,　the　rise　in　disease　burden　is　more　pronounced　in　economically　underdeveloped　regions　than　in　developed　areas.　Conclusion:　From　1990　to　2021,　the　global　burden　of　bipolar　disorder　has　shown　a　persistent　upward　trend,　with　marked　disparities　observed　across　regions　with　varying　SDI　levels.　High-SDI　regions　consistently　demonstrate　elevated　incidence　and　prevalence　rates,　whereas　low-SDI　regions　are　grappling　with　a　progressively　significant　disease　burden.　These　findings　highlight　the　need　for　increased　investment　in　the　global　mental　healthcare　system.　Particular　priority　should　be　given　to　strengthening　support　for　healthcare　systems　in　low-income　and　resource-poor　areas.　©　2025