Mental health literacy mediates associations of self rated health and chronic disease status with anxiety and depression in Chinese residents.

Anxiety and depression are important mental health problems worldwide, and their comorbid state, anxiety-depression comorbidity (ADC) , has greater symptom severity. With the increasing burden of chronic non-communicable diseases, residents' physical and mental health problems have shown an overlapping trend. The mediating role of mental health literacy (MHL) between physical health and psychological outcomes warrants further investigation. Based on the national survey initiative, this study conducted a large-scale stratified multistage population survey across all districts and counties of Chongqing, southwest China, and included 36,874 permanent residents. Mental health literacy (MHL) was assessed using the National Mental Health Literacy Questionnaire (NMHLQ). Depression and anxiety were screened using the Patient Health Questionnaire-9 (PHQ-9) and the Generalized Anxiety Disorder-7 (GAD-7), respectively. Descriptive analyses were performed to characterize epidemiological features. Multivariable regression analysis was conducted across the three psychological outcome groups of anxiety, depression, and their comorbidity to explore the effects of self-rated health (SRH) and chronic disease on multiple psychological outcomes and the effects after variable adjustment, and subgroup analysis and sensitivity analysis were used to test robustness. The Bootstrap resampling method was used to test the mediating effect, and the standardized path coefficients and effect proportions of each mediation model were calculated. The positive screening rates for anxiety, depression, and ADC in the surveyed area were 2.72% (1004/36874), 4.53% (1672/36874), and 2.11% (777/36,874), respectively. The odds of anxiety, depression, and comorbidity among residents with fair or poor SRH were 2.76 (95% CI 2.40-3.17), 3.31 (95% CI 2.97-3.69), and 2.98 (95% CI 2.55-3.49), respectively. The corresponding odds among residents with chronic disease were 1.40 (95% CI 1.21-1.62), 1.51 (95% CI 1.35-1.70), and 1.41 (95% CI 1.19-1.65), respectively. MHL was negatively associated with the three psychological outcomes. After adjustment for relevant covariates, stratified analysis, and sensitivity analysis, the above associations remained robust. Multivariable logistic regression and multi-group mediation effect analysis showed that MHL had an independent protective role and played a 7-8% partial mediating role in the effects of SRH and chronic disease on mental health outcomes. Poor SRH and chronic disease were associated with anxiety, depression, and their comorbidity among residents, and MHL had an independent protective and partial mediating role in these associations. These findings suggest that residents' MHL should be improved, and integrated interventions combining chronic disease management with psychological screening should be strengthened.