Thirty-year trends of depressive disorders in 204 countries and territories from 1990 to 2019: An age-period-cohort analysis

This study aims to estimate the global, regional, and national burden of depressive disorders in 204 countries and territories from 1990 to 2019. All data were obtained from the 2019 Global Burden of Disease (GBD) study. Age-period-cohort (APC) modeling was conducted to disentangle age, period, and birth cohort effects on depression incidence. We compared these estimates across regions classified based on their socio-demographic index (SDI). The Estimated Annual Percentage Change (EAPC) was calculated for each of the 204 countries and territories to identify the top five countries with increased depression incidence (Spain, Mexico, Malaysia, the United States of America, and Uruguay) and the top five countries with decreased depression incidence (Singapore, Estonia, Cuba, Maldives, and Sri Lanka). The results from APC analysis indicate that although depression incidence has decreased globally, the incidence rate in high SDI regions is still increasing, especially in the younger generations. Findings suggest that currently some populations are in need of receiving more psychological support (i.e., individuals born after 1950s in high SDI regions; males in middle SDI regions). Forthcoming studies could corroborate our findings using individual-level data which may guide future prevention and intervention of depression in high-risk populations or regions.