The trends of mental disorders mortality in China over a 33-year period

Objectives: We investigated the variations in the trends of mental disorders mortality by age, period, and cohort, over a 33-year period from 1987 to 2020, to reveal the relationship between age, period, cohort, and mental disorders mortality, as well as providing guidance for resource allocation to prevent mental disorders-related deaths in vulnerable target populations. Methods: The data of mental disorders mortality 1987-2020 were from five administrative organizations, which collected from the National Health Commission in China with national monitoring by sex and age, covering 31 provinces in China. The International Classification of Diseases (ICD), its 9th Revision (ICD-9) and its 10th Revision were used to code the mental diseases. From 1987-2002, ICD-9 was used, and ICD-10 was used from 2003 to 2020. The age standardized mortality rates (ASMRs) were calculated using the World Standard Population as the reference. We used joinpoint models to assess the trends of mental disorders mortality in China for the period 1987-2020. And the age-period-cohort models were employed to estimate the age-period-cohort effect on mental disorders mortality. Results: The age-standardized overall mental disorders mortality rate (ASMR) showed a downward trend from 1987 to 2020. Further, the ASMR of individuals in urban was higher than that in rural from 1987 to 2001, but, post-2002, this urban-rural disparity in ASMR showed a less clear pattern, with urban areas occasionally surpassing rural areas and vice versa. ASMR is less prevalent among females compared to males overall. The contribution of age effects to mental disorders mortality gradually increases with advancing age, the period effects of mental disorders mortality gradually decrease over time. The cohort effect's contribution to mental disorders mortality decreases in the newly born population, while in the older birth cohorts, the cohort effect's contribution to the mortality rate of mental disorders increases. Conclusions: The ASMR exhibits a decreasing trend from 1987 to 2020, and these change trend showed urbanrural and sex differences. The primary factors contributing to this overall decline are period effects and cohort effects. Our results provide valuable information for shaping mental health policies, designing targeted interventions, and preparing for future changes in disease mortality rates. The focus on different demographic factors allows for a nuanced and tailored approach to mental health promotion and intervention strategies.