Global substance use disorders burden from 1990 to 2021: post-COVID shifts and widening inequalities.

BACKGROUND

Global evidence on substance use disorders (SUDs) remains fragmented, and fewer analyses have benchmarked country-level burden against development gradients. We used Global Burden of Disease 2021 estimates to update long-term trends and inequalities in SUDs, including alcohol use disorder and drug use disorders (DUDs), from 1990 to 2021.

METHODS

We analysed Global Burden of Disease 2021 estimates for SUDs, alcohol use disorder, and DUDs across 204 countries and territories. We report age-standardised prevalence rates (ASPR), incidence rates, and disability-adjusted life-years rates (age-standardised disability-adjusted life-years rate) per 100 000 population with 95% uncertainty intervals (UI). Analyses examined temporal trends, age-sex patterns, regional and national variation, socio-demographic index (SDI) - stratified gradients, and deviations of observed burden from SDI-based expected levels.

RESULTS

In 2021, 162.86 million people had SUDs (95% UI = 145.95, 180.85). The global ASPR was 1982.13 per 100 000 (95% UI = 1773.57, 2206.29), declining by 16.9% (95% UI = -18.7, -14.9) since 1990; age-standardised incidence rate was 843.37 (95% UI = 736.21, 956.19), declining by 17.3% (95% UI = -19.7, -15.2); and ASDR was 393.36 (95% UI = 323.56, 469.04), declining by 9.1% (95% UI = -11.9, -5.7). Alcohol use disorder accounted for about 111.12 million cases (95% UI = 96.35, 127.90) (ASPR = 1335.43; 95% UI = 1153.65, 1539.75), and DUDs for about 53.12 million (95% UI = 46.99, 60.95) (ASPR = 663.80; 95% UI = 584.52, 766.14). Geographic heterogeneity was marked: high-income North America had the highest ASDR = 2193.48 (95% UI = 1861.45, 2529.02) and Western Sub-Saharan Africa the lowest ASDR = 136.22 (95% UI = 108.18, 170.26). Drug use disorder burden increased in several high-SDI settings in 2020-2021, while burden peaked in young adults (approximately 25-35 years) and was consistently higher among males.

CONCLUSIONS

Despite declining global age standardised rates since 1990, SUDs remain a major source of health loss, with pronounced age-sex differences, substantial cross-country heterogeneity, and widening divergence by development level. Recent increases in drug-related burden in some high-SDI settings highlight the need for strengthened surveillance and context-specific prevention, treatment, and harm-reduction responses.