Social Value and Public Health: Exploring the Impact of Social Connection on the Community Mental Health

Background: Social connection is widely recognized as a protective determinant of health, yet its direct and indirect effects on mental health remain underexplored. This study examines the relationship between social connection and mental health, focusing on the mediating role of quality of life (QoL) and the moderating effect of regional differences. Methods: We analyzed data from the 2019 Korean Community Health Survey, comprising 229,099 adults. Mental health was assessed through validated measures of depressive symptoms and psychological well-being. Social connection was measured using indicators of interpersonal ties and community participation, and QoL was assessed via self-reported health-related satisfaction across major life domains. Analytical procedures included mediation modeling and subgroup analyses by region, with significance levels set at p < 0.05. Results: The results indicate that social connections are significantly associated with lower stress levels and reduced depressive symptoms, with QoL playing a critical mediating role. Notably, the indirect effect of social connection on mental health via QoL is stronger in rural areas compared to urban regions, highlighting the importance of social cohesion and community support in mental well-being. Among 203,567 adults, greater social participation was associated with lower subjective stress (total effect = −0.052, p < 0.001) and fewer depressive symptoms (PHQ-9 total effect = −0.308, p < 0.001). QoL significantly mediated these associations, with the strongest indirect pathways observed through usual activities (19.2% for stress; 27.6% for depression) and mobility (24.4% for depression). Regional analysis showed stronger mediation in rural areas (up to 26.8% for stress and 32.6% for depression) than in urban areas (8–16% and 14.9–23%). Direct effects remained significant, indicating partial mediation. These findings highlight that social participation enhances mental health directly and indirectly through QoL, particularly in rural contexts. Conclusions: Social connection contributes to better mental health both directly and indirectly through improved QoL, with stronger effects observed in rural communities. These findings highlight the importance of fostering social cohesion and enhancing life quality as strategies for improving population mental health. Policy interventions should adopt context-sensitive approaches that account for regional differences in social resources and service availability.