title: Income inequality and schizophrenia: increased schizophrenia incidence in countries with high levels of income inequality.
abstract: BACKGROUND
  Income inequality is associated with numerous negative health outcomes. There is evidence that ecological-level socio-environmental factors may increase risk for schizophrenia.
  
  
  OBJECTIVE
  The aim was to investigate whether measures of income inequality are associated with incidence of schizophrenia at the country level.
  
  
  METHODS
  We conducted a systematic review of incidence rates for schizophrenia, reported between 1975 and 2011. For each country, national measures of income inequality (Gini coefficient) along with covariate risk factors for schizophrenia were obtained. Multi-level mixed-effects Poisson regression was performed to investigate the relationship between Gini coefficients and incidence rates of schizophrenia controlling for covariates.
  
  
  RESULTS
  One hundred and seven incidence rates (from 26 countries) were included. Mean incidence of schizophrenia was 18.50 per 100,000 (SD = 11.9; range = 1.7-67). There was a significant positive relationship between incidence rate of schizophrenia and Gini coefficient (β = 1.02; Z = 2.28; p = .02; 95% CI = 1.00, 1.03).
  
  
  CONCLUSIONS
  Countries characterized by a large rich-poor gap may be at increased risk of schizophrenia. We suggest that income inequality impacts negatively on social cohesion, eroding social capital, and that chronic stress associated with living in highly disparate societies places individuals at risk of schizophrenia.
authors.affiliation: 1Department of Psychiatry, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Burns
authors.forename: Andrew
authors.initials: A
authors.lastname: Tomita
authors.forename: Amy S
authors.initials: AS
authors.lastname: Kapadia
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D015994:Incidence; D007182:Income / Q000706:statistics & numerical data*; D038622:Internationality; D008297:Male; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology*; D012959:Socioeconomic Factors
keywords: Gini coefficient; Schizophrenia; income inequality; systematic review