The mediating and moderating roles of physical sub-health in the relationship between family functioning and mental health problems among Chinese adolescents.

BACKGROUND

Adolescent mental health is shaped by both family environments and physical well-being. However, the role of physical sub-health, a state of functional imbalance and fatigue prior to diagnosable illness, remains poorly understood in this process. This study examined whether physical sub-health serves both as a psychosomatic pathway and as a vulnerability factor linking family functioning to adolescent mental health.

METHODS

A cross-sectional survey was conducted among 647 primary and secondary school students across China. Validated scales were used to assess family functioning, physical sub-health (operationalized based on constitution characteristics), and mental health symptoms. Structural equation modeling (SEM) was employed to examine the mediating role of physical sub-health. Furthermore, latent moderated structural equation modeling (LMS) was applied to test its moderating effect.

RESULTS

Physical sub-health significantly mediated the association between family functioning and mental health, with the largest indirect effects observed for qi stagnation (β = -0.27, 95% CI [-0.36, -0.20]), qi deficiency (β = -0.13, 95% CI [-0.17, -0.10]), and phlegm dampness (β = -0.12, 95% CI [-0.15, -0.08]). These findings suggest that functional bodily imbalance may help explain how family stress is related to emotional and behavioral difficulties. In addition, physical sub-health moderated this association, with adolescents showing poorer physical resilience being more susceptible to the detrimental effects of dysfunctional family environments.

CONCLUSION

Physical sub-health plays a dual psychosomatic role in how family functioning relates to adolescent mental well-being, acting as both a mechanism and a vulnerability factor. These findings highlight the potential value of integrated public health strategies that combine family support, school-based identification of psychosomatic risk, and routine health promotion to strengthen youth psychosomatic resilience. TRIAL REGISTRATION: The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board (or Ethics Committee) of Ethics Committee of Beijing University of Chinese Medicine (protocol code No: 2023BZYLL1101 and date of approval: 2023.11.10).