Global epidemiological survey, burden of disease assessment and spatio-temporal prediction of bipolar disorder from 1990 to 2021 based on spatial clustering analysis

Bipolar disorder is a lifelong mental disorder. Late diagnosis increases treatment difficulty and costs, and age-related decline in liver and kidney function may affect drug metabolism and efficacy. This study assesses the global disease burden, geographical distribution, influencing factors, and future trends from 1990 to 2021. Data from the GBD 2021 were used to evaluate age-standardized incidence, prevalence, and DALYs for bipolar disorder, and analyze influencing factors. Temporal trends were analyzed using Joinpoint regression, while future trends were projected with Bayesian Age-Period-Cohort models. Spatial distribution was assessed via cold-spot and hot-spot analyses. From 1990-2021, the incidence, prevalence, and DALYs of bipolar disorder in individuals aged 60 and older in H-SDI regions were significantly higher than those in L-SDI regions (P < 0.05), with H-SDI regions showing a declining trend, while the increase in these factors in L-SDI regions was substantially greater than in H-SDI regions (P < 0.05). Although the incidence peaks at ages 15-19, the economic burden and prevalence gradually shift towards older adults, with the peak moving from the 20-24 age group to 25-29, and a significant increase in prevalence and DALYs among individuals aged 25 and older in middle and lower SDI regions. By 2021, the spatial dimension of substance abuse and child abuse showed improvement, particularly in Australia and New Zealand, while alcohol abuse in Russia rose to 235.89. Cold-spot and hot-spot analysis highlighted the contraction of cold spots and the expansion of hot spots, especially in Central Africa and the Mediterranean region. Future projections, based on current trends and models, suggest a slight decrease in global disease burden by 2030, with a more significant reduction for males. By 2021, both spatiotemporal trends show signs of deterioration, with significant regional and gender differences. Although projections indicate a decline in disease burden in the future, current focus should remain on the intergenerational impact of child abuse on mania, the accumulation of disease burden among the older adults and the phenomenon of alcoholism in high-latitude regions such as Eurasia.