Abstract
BACKGROUND: Major depressive disorder (MDD) poses a significant global public health challenge, contributing substantially to disability and mortality. Despite its widespread impact, the burden of MDD varies considerably across different countries due to distinct sociocultural, economic, and healthcare contexts. This study compares the burden of MDD in China, India, and the United States of America from 1990 to 2021, employing a cross-national age-period-cohort analysis using data from the Global Burden of Disease (GBD) 2021 study. We also project future trends in MDD burden up to 2035. METHODS: Data on MDD prevalence, years lived with disability (YLDs), and age-standardized prevalence rates (ASPR) and age-standardized YLD rates (ASYR) were obtained from the GBD 2021 database. We employed statistical methods including Joinpoint regression, Bayesian age-period-cohort (BAPC) modeling, and the calculation of the average annual percentage change (AAPC) to analyze trends and forecast future MDD burden across the three countries. RESULTS: Between 1990 and 2021, the number of MDD cases increased in all three countries, with marked variations in age-standardized rates. In China, ASPR and ASYR showed modest declines, with a notable decrease in the younger age groups, while older adults, particularly those aged 70-74, experienced rising rates. India demonstrated more stability in age-standardized rates, while the United States of America saw a pronounced increase in both prevalence and YLDs. Gender disparities were evident in all countries, with females consistently bearing a higher burden than men. Projections for 2035 suggest that the MDD burden will continue to rise in the United States, while trends in China are expected to slightly decrease and remain relatively stable in India. CONCLUSIONS: The escalating burden of MDD, particularly in the United States of America, highlights the urgent need for tailored interventions that address the specific demographic and sociocultural factors influencing mental health in each country. In China and India, the growing absolute number of MDD cases calls for strengthened mental health services, especially for older adults and women, while in the United States of America, tackling rising prevalence among younger populations and addressing underlying socioeconomic inequalities will be crucial. Implementing comprehensive mental health strategies, including improved access to care and targeted preventive interventions, are essential to alleviate the future impact of MDD in these countries.