Global, regional, and national burden of mental disorders and substance use disorders in older adults from 1990 to 2021: a systematic analysis and future trend prediction study.

Introduction: As the global population ages, mental health has become a major public health issue affecting healthy aging. To estimate the burden, trends, and inequalities of mental disorders and substance use disorders (SUDs) among older adults aged ≥60 years at the global, regional, and national levels from 1990 to 2021. Methods: Data from the Global Burden of Disease Study 2021. The study focused on the burden of mental health conditions, analyzing mental disorders and SUDs prevalence, years lived with disability (YLDs), and average annual percentage change (AAPC), encompassing eight age groups (60-64 years, 65-69 years, 70-74 years, 75-79 years, 80-84 years, 85-89 years, 90-94 years, ≥95 years) for both men and women. Results: Globally in 2021, 1.09 billion individuals aged ≥60 years included 161.3 million (14.8%) with mental disorders and 19.2 million (1.8%) with SUDs. Mental disorders accounted for 22.8 million YLDs versus 2.10 million from SUDs in this population. From 1990 to 2021, age standardized prevalence of mental disorders increased by 3.7%, while SUDs declined by 8.7%, with lower SDI levels correlating with higher YLDs burdens overall. Over the next fifteen years, projections indicating stagnant trends in SUDs alongside slight declines in mental disorders highlight persistent unmet needs. Discussion: Global population aging demands heightened prioritization of mental healthcare for older adults. Today, mental and substance use disorders persist as major contributors to disease burden in this population. Our findings call for equitable mental resource allocation, age-adapted diagnostic tools, and policies targeting late-life psychosocial vulnerabilities.