Pathways linking perceived stress to occupational burnout among medical staff in county-level hospitals in China: a moderated mediation study

Background Occupational burnout is prevalent among medical staff in county-level hospitals in China. Drawing on Conservation of Resources theory and Psychological Capital Theory, this study examined the pathways from perceived stress to occupational burnout, focusing on the serial mediating roles of psychological capital and mental health problems, and the moderating role of social support. Methods A convenience sampling method was used to conduct a questionnaire survey among 662 in-service medical staff from three county-level hospitals in Nanjing between January and March 2025. The research instruments included the Perceived Stress Scale, Psychological Capital Questionnaire, General Health Questionnaire, Social Support Rating Scale, and Maslach Burnout Inventory-General Survey. SPSS 29.0 and Mplus 8.3 with Bootstrap (5000 resamples) were used for moderated mediation analysis. Results The prevalence of occupational burnout among medical staff in county-level hospitals was 73.3%. Perceived stress was significantly and positively correlated with occupational burnout and mental health problems ( P  < 0.05) and significantly and negatively correlated with psychological capital and social support ( P  < 0.05). Psychological capital and social support were significantly and positively correlated with each other ( P  < 0.05), and both were significantly and negatively correlated with occupational burnout and mental health problems ( P  < 0.05). Path analysis demonstrated that perceived stress directly and positively predicted occupational burnout. Perceived stress was also indirectly associated with occupational burnout through the independent mediating roles of psychological capital and mental health problems, as well as the serial mediating pathway from psychological capital to mental health problems. Decomposition of effects indicated that the mediating effect of psychological capital accounted for the largest proportion. Further analysis revealed that social support significantly moderated the impact of psychological capital on mental health problems, and the serial mediating effect gradually strengthened with increasing levels of social support. Conclusions Perceived stress is a key risk factor for burnout. Psychological capital and mental health problems mediate this relationship in independent and serial pathways, while social support enhances the protective effect of psychological capital. Interventions should target stressor reduction, psychological capital development, mental health support, and organizational environments in county-level hospitals.