The association of social capital with depression and quality of life in school-aged children.

Social capital is an important factor that affects mental health. The purpose of this study was to examine the relationship between social capital and depression and between social capital and quality of life (QoL) in children in elementary and junior high school and to examine how this relationship differs in relevant patterns at both the individual- and school-level. The study was conducted in all elementary and junior high schools in a single municipality; the subjects consisted of 3,722 elementary school and 3,987 junior high school students (aged from 9 to 15). A multilevel linear mixed effect model analysis revealed that all three subscales of social capital were associated with depression and QoL at the individual-level: The school social capital at the individual-level showed the strongest association with depression and QoL. We also found that some of social capital at the school-level was associated with depression and QoL. An interactive effect was observed between educational stage (elementary and junior high) and some of social capital subscales. Specifically, the inverse association between school social capital and depression was stronger among the junior high students, while the positive association between school and neighborhood social capital and QoL was stronger among the elementary students. These interactions suggest that social capital impacts depression and QoL differently in elementary and junior high students. These findings suggest that the degree of association of social capital domains differs in mental health among the educational stage.