title: Social capital and common mental disorder: a systematic review.
abstract: OBJECTIVE
  This study aims to systematically review all published quantitative studies examining the direct association between social capital and common mental disorders (CMD). Social capital has potential value for the promotion and prevention of CMD. The association between different types of social capital (individual cognitive and structural, and ecological cognitive and structural) and CMD must be explored to obtain conclusive evidence regarding the association, and to ascertain a direction of causality.
  
  
  METHODS
  10 electronic databases were searched to find studies examining the association between social capital and CMD published before July 2014. The effect estimates and sample sizes for each type of social capital were separately analysed for cross-sectional and cohort studies. From 1857 studies retrieved, 39 were selected for inclusion: 31 cross-sectional and 8 cohort studies. 39 effect estimates were found for individual level cognitive, 31 for individual level structural, 9 for ecological level cognitive and 11 for ecological level structural social capital.
  
  
  RESULTS
  This review provides evidence that individual cognitive social capital is protective against developing CMD. Ecological cognitive social capital is also associated with reduced risk of CMD, though the included studies were cross-sectional. For structural social capital there was overall no association at either the individual or ecological levels. Two cross-sectional studies found that in low-income settings, a mother's participation in civic activities is associated with an increased risk of CMD.
  
  
  CONCLUSIONS
  There is now sufficient evidence to design and evaluate individual and ecological cognitive social capital interventions to promote mental well-being and prevent CMD.
authors.affiliation: School of Physical & Occupational Therapy, McGill University, Montreal, Quebec, Canada Centre for Global Mental Health, London School of Hygiene and Tropical Medicine, London, UK Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK.
authors.forename: Annahita M
authors.initials: AM
authors.lastname: Ehsan
authors.affiliation: Centre for Global Mental Health, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Mary J
authors.initials: MJ
authors.lastname: De Silva
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015982:Bias; D003430:Cross-Sectional Studies; D016206:Databases, Bibliographic; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D008137:Longitudinal Studies; D001523:Mental Disorders / Q000191:economics / Q000209:etiology / Q000517:prevention & control*; D008875:Middle Aged; D065840:Protective Factors; D012307:Risk Factors; D066270:Social Capital; D012931:Social Environment; D012959:Socioeconomic Factors; D055815:Young Adult
keywords: MENTAL HEALTH; PSYCHIATRY; SOCIAL CAPITAL; SYSTEMATIC REVIEWS