A prospective study of individual-level social capital and major depression in the United States.

STUDY OBJECTIVE To investigate prospectively the associations between depression and cognitive social capital (social trust, sense of belonging, mutual aid) and structural social capital (volunteer work and community participation). METHODS This was a prospective study that was carried out in the USA. The participants were a nationally representative sample of 724 English-speaking non-institutionalised adults (25-74 years old) who participated in the National Survey of Midlife Development in the United States (MIDUS) in 1995-6 and the MIDUS Psychological Experience Follow-Up study in 1998. MAIN RESULTS In multivariable adjusted logistic regression analyses, those who trusted their neighbours were less likely to develop major depression (MD) during follow-up than those who reported low levels of social capital on these dimensions (adjusted OR of MD for high vs low trust = 0.43; 95% CI 0.20 to 0.93, adjusted for MD at baseline, age, gender, race, education, working status, marital status, physical health and extroversion traits). Structural dimensions of social capital were not associated with MD in adjusted models. CONCLUSIONS Perceptions of higher levels of cognitive social capital (trust of neighbours) are associated with lower risks of developing MD during 2-3 year follow-up. However, after excluding participants with MD at the baseline, the association between trust and MD became non-significant. Structural dimensions were not associated with MD.