Divergent Trajectories of Youth Mental Health in Emerging Economies: A Global Burden of Disease Analysis of Anxiety and Autism Spectrum Disorders in BRICS Nations (1990–2030)

Purpose: Adolescent mental wellbeing in newly industrializing regions represents a pivotal yet underexplored frontier in public health. The BRICS bloc—encompassing Brazil, Russia, India, China, and South Africa—confronts a distinct “double burden” of disease amidst accelerated socioeconomic stratification. This investigation quantified the disease burden and delineated forecasting trajectories for anxiety disorders and autism spectrum disorders (ASD) within the 5– 24 age cohort across these nations. Patients and Methods: Using data derived from the Global Burden of Disease (GBD) Study 2021, the study evaluated Age-standardized rates (ASR) of prevalence alongside disability-adjusted life years (DALYs). Temporal evolution from 1990 through 2021 was gauged via Estimated Annual Percentage Change (EAPC). Future burden dynamics up to 2030 were extrapolated employing linear regression models rooted in historical epidemiological patterns. Results: In 2021, Brazil registered the highest age-standardized anxiety prevalence (7661.9 per 100,000), whereas the Russian Federation dominated in ASD prevalence (996.2 per 100,000). A pronounced divergence in temporal trends emerged: India witnessed the steepest surge in anxiety prevalence (EAPC = +0.91%, 95% CI 0.46 to 1.35), contrasting sharply with China, which exhibited a significant secular decline (EAPC = − 0.26%). Projections indicate that anxiety rates in Brazil and India may remain elevated through 2030. ASD prevalence remained relatively stable across nations, with cross-national variations likely reflecting differences in diagnostic capacity and awareness rather than true epidemiological shifts. Demographic stratification corroborated a female preponderance in anxiety, identifying young adulthood (20– 24 years) as the critical risk window. Conclusion: The escalating anxiety trajectory in India, paralleled by persistent high burdens in Brazil, is associated with rapid urbanization and multifactorial societal stressors that may amplify youth mental vulnerabilities. Projections to 2030 should be interpreted as scenario-based estimates rather than definitive predictions, given the inherent uncertainty of linear extrapolation. Tailored, culturally specific interventions targeting young adults and addressing within-country disparities are warranted. Plain Language Summary: Many young people in emerging economies experience mental health challenges such as anxiety and autism spectrum conditions, yet we know little about how these patterns differ across countries. Understanding these differences matters because targeted support can only be designed when the specific needs of young people in each country are clear. This study used data from the Global Burden of Disease study to track how anxiety and autism spectrum conditions affected young people aged 5– 24 in Brazil, Russia, India, China, and South Africa from 1990 to 2021. We found that anxiety is rising sharply among young people in Brazil and India, while it has decreased in China. Differences in autism rates across countries likely reflect how well each country identifies and diagnoses autism rather than true differences in how many young people are affected. If current trends continue, the number of young people experiencing anxiety in Brazil and India may remain high through 2030. For young people and their families, this means that countries like Brazil and India need to invest more in accessible mental health services, particularly for those in the 20– 24 age group who are most affected. These results call for each country to develop support systems that respond to the unique challenges their young people face. Keywords: anxiety, autism spectrum disorder, BRICS, global burden of disease, epidemiology, forecasting