Incidence and prevalence of dysthymia among young adults in China, 1990-2021, with forecasts to 2046: an age-period-cohort analysis of the Global Burden of Disease Study 2021.

Background: Dysthymia, a chronic depressive disorder, poses a significant public health challenge due to its prolonged course and substantial impact on quality of life, particularly among high-risk populations such as young adults. This study aims to investigate trends in dysthymia incidence and prevalence among young adults in China from 1990 to 2021 and to project future patterns through 2026.

Methods: Using data from the Global Burden of Disease (GBD) 2021 Study, we conducted an Age-Period-Cohort (APC) analysis to assess the relative risks (RRs) of dysthymia incidence and prevalence among Chinese young adults aged 20-44 years from 1990 to 2021. Bayesian and Nordpred APC models were applied to forecast age-standardized incidence rates (ASIR) and prevalence rates (ASPR) for the next 25 years (2022-2046).

Results: Between 1990 and 2019, both ASIR and ASPR of dysthymia exhibited a declining trend. Among females, ASIR decreased from 363.099 (95% uncertainty interval [UI]: 339.146, 387.051) per 100,000 population to 318.100 (95% UI: 296.812, 339.388), while among males, it declined from 232.757 (95% UI: 216.022, 249.492) to 208.467 (95% UI: 193.617, 223.317). Similarly, ASPR decreased from 2,072.562 (95% UI: 1,813.254, 2,331.870) to 1,795.234 (95% UI: 1,582.628, 2,007.841) for females and from 1,278.432 (95% UI: 1,116.869, 1,439.994) to 1,131.620 (95% UI: 994.059, 1,269.180) for males. However, a marked increase was observed from 2020, with 2021 rates approaching 1990 levels for both sexes. APC analysis showed that RRs for dysthymia incidence and prevalence increased with age, particularly beyond 35-39 years. More recent cohorts demonstrated lower RRs compared to earlier cohorts, whereas period effects remained relatively stable. Projections indicate a continuous rise in ASIR and ASPR from 2022 to 2046 for both sexes. Throughout the study period, dysthymia prevalence rates consistently exceeded incidence rates, with females exhibiting higher rates than males.

Conclusion: Enhancing early diagnostic capabilities in primary care, advancing standardized treatment strategies, improving mental health literacy through health education and social media, and implementing targeted interventions for high-risk groups-particularly young women and individuals in early adulthood-are essential for alleviating the burden of dysthymia in China and other countries with similar demographic and epidemiological characteristics.