The global burden of mental and substance use disorders among adolescents and young adults

Mental disorders and substance use disorders (SUDs) are significant public health challenges among adolescents and young adults (AYAs). This study quantified global and regional prevalence, disability-adjusted life-years (DALYs), and years lived with disability (YLDs), and temporal trends of mental disorders and SUDs among AYAs from 1990-2021. Estimates were generated using DisMod-MR 2.1, with standardized case definitions, severity weights, and pandemic-period adjustments. Temporal trends were assessed with Joinpoint regression. In 2021, the global point prevalence of mental disorders was 15.2% in adolescents, and 16.1% among young adults, with anxiety disorders being the most common condition. Mental disorders were the leading cause of YLDs and DALYs in 2021. High-income regions exhibited the highest rates of mental disorders. Significant sex differences were observed, with higher prevalence of attention-deficit hyperactivity disorder and autism spectrum disorders in males, and anorexia nervosa was more prevalent in females. SUDs were the 15th cause of YLDs and 22nd cause of DALYs among adolescents and ranked 8th for YLDs and 11th for DALYs for young adults. During the pandemic, a significant increase in the prevalence of mental disorders and a decline in SUDs was observed. DALYs for mental disorders increased significantly during the pandemic, especially for depressive and anxiety disorders, with higher DALYs in females than males. Mental disorders remain a leading cause of disability in AYAs worldwide, with a marked surge during 2019-2021. Although SUDs declined, the rising burden of depression and anxiety demonstrated urgent needs for age-specific, sex-responsive, and regionally tailored mental health strategies.