Does social capital buffer or exacerbate mental health inequality? Evidence from the China Family Panel Study (CFPS)

BACKGROUND: Health inequality, including physical and mental health inequality, is an important issue. What role social capital plays in mental health inequality is still ambiguous, especially in developing countries. The aim of this study is to explore the relationship between social capital and mental health inequality in China. METHOD: Both family-level and community-/village-level social capitals are included in our analysis. Data is mainly extracted from the China Family Panel Studies in 2018, and lagged term of social capital in CFPS 2016 was used to link with other variables in 2018. Depressive symptoms and subjective well-being are set as indicators of mental health. A series of OLS regression models were conducted to estimate the effects of social capital on mental health and mental health inequality. RESULTS: Higher levels of social capital and income are related to a lower level of depressive symptoms and a higher level of subjective well-being. The positive coefficient of interaction term of family-level social capital and income level in the urban area indicates that the inhibiting effect of social capital on depressive symptoms is pro-poor. The negative coefficient of interaction term of village-level social capital and income level in the rural area suggests that the promoting effect of social capital on subjective well-being is pro-poor, too. CONCLUSION: The results show that severe mental health inequality exists in China; family-level social capital can buffer depressive symptom inequality, and village-level social capital can buffer SWB inequality. Although the amount of social capital of the poor is less than the rich, the poor can better use social capital to improve their mental health. Our study advocates enhancing social participation and communication for the poor to reduce mental health inequality. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12939-022-01642-3.