Global, regional and national burdens of schizophrenia in adolescents and young adults: a trend analysis and forecast from 1990 to 2021.

Schizophrenia is a serious psychological illness that tends to occur during the teens or early adulthood years. It causes major disability and social impairment. However, few studies have examined its global burden among adolescents and young adults. This study utilised data from the 2021 Global Burden of Disease Study to evaluates long-term trends and forecasts the future burden in this age group. The global rate for age-standardized incidence rate (ASIR), Aprevalence rate (ASPR), and rate of disability-adjusted life years (ASDR) from 1990 to 2021 reduced gradually (AAPC < 0, p < 0.05). However, the actual number rose for incident from 0.41 million to 0.48 million, for prevalence from 1.71 million to 2.00 million, and for Disability-Adjusted Life Years(DALYs) from 1.14 million to 1.33 million. The rate for males was higher for both ASIR and ASDR for both sexes, and for both, the highest burden was in the group aged 20-24 years. Regionally, Australasia and East Asia showed the highest rates, while Eastern Europe reported the lowest. High-middle the Sociodemographic Index (SDI) countries carried the greatest burden. Inequality analyses indicated widening disparities, with greater concentration of burden in high-SDI regions. Decomposition analysis showed population growth as the main driver of increasing burden. Under the historical-trend continuation scenario, point estimates of ASIR, ASPR, and ASDR are projected to increase modestly through 2040, although prediction intervals widen substantially. Although age-standardized rates of schizophrenia among youth declined, the absolute burden increased due to demographic growth. The highest risks were observed in late adolescence and early adulthood, with males more affected than females. Regional and SDI disparities persist and may widen. Early detection and targeted interventions are needed to reduce the future burden of schizophrenia in young populations.