Global burden and trends in mental disorders among older adults in the BRICS countries from 1990 to 2021, with projections to 2050: a cross-sectional study

Background Mental disorders are a growing cause of disability among older adults in BRICS countries, where large population and rapid aging present a significant public health challenge. A comprehensive assessment of disease burden is urgently needed. Methods Data from the Global Burden of Disease Study 2021, we estimated prevalence and years lived with disability (YLDs) for depressive disorders, anxiety disorders, bipolar disorder, schizophrenia, and substance use disorders among older adults(1990–2021) in BRICS. Subgroup analyses by age and sex were performed, and Bayesian age-period-cohort models projected trends until 2050. Results In 2021, depressive disorders (33.5 million) and anxiety disorders (23.1 million) were the most prevalent, with higher rates in females. Alcohol use disorders (8.1 million) were far common than drug use disorders (0.78 million), and more prevalent in males. From 1990 to 2021, prevalence of anxiety disorders rose by 262.6%, while drug use disorders declined by 276.3%. YLDs increased substantially for anxiety disorders (254.1%, 95% UI: 47.8–480.9%) and depressive disorders (98.8%, 95% UI: -63.6–275.2%), whereas drug use disorders declined markedly (-398.9%, 95% UI: -655.3% to -99.4%). Projection analyses indicate that the burden of mental disorders among older adults will increase in most BRICS countries during 2021–2050. Conclusions The prevalence and burden of mental disorders on older adults in BRICS countries are rising and will likely continue increasing until 2050. Strengthened mental health systems and targeted interventions are crucial to meet the growing needs of aging populations in these low- and middle-income countries.