title: Exposure to genocide and the risk of schizophrenia: a population-based study.
abstract: BACKGROUND
  No evidence exists on the association between genocide and the incidence of schizophrenia. This study aims to identify critical periods of exposure to genocide on the risk of schizophrenia.
  
  
  METHODS
  This population-based study comprised of all subjects born in European nations where the Holocaust occurred from 1928 to 1945, who immigrated to Israel by 1965 and were indexed in the Population Register (N = 113 932). Subjects were followed for schizophrenia disorder in the National Psychiatric Case Registry from 1950 to 2014. The population was disaggregated to compare groups that immigrated before (indirect exposure: n = 8886, 7.8%) or after (direct exposure: n = 105 046, 92.2%) the Nazi or fascist era of persecutions began. The latter group was further disaggregated to examine likely initial prenatal or postnatal genocide exposures. Cox regression modelling was computed to compare the risk of schizophrenia between the groups, adjusting for confounders.
  
  
  RESULTS
  The likely direct group was at a statistically (p < 0.05) greater risk of schizophrenia (hazard ratio = 1.27, 95% confidence interval 1.06-1.51) than the indirect group. Also, the likely combined in utero and postnatal, and late postnatal (over age 2 years) exposure subgroups were statistically at greater risk of schizophrenia than the indirect group (p < 0.05). The likely in utero only and early postnatal (up to age 2 years) exposure subgroups compared with the indirect exposure group did not significantly differ. These results were replicated across three sensitivity analyses.
  
  
  CONCLUSIONS
  This study showed that genocide exposure elevated the risk of schizophrenia, and identified in utero and postnatal (combined) and late postnatal (age over 2 years) exposures as critical periods of risk.
authors.affiliation: Department of Community Mental Health,Faculty of Social Welfare and Health Sciences,University of Haifa,Haifa,Israel.
authors.forename: S Z
authors.initials: SZ
authors.lastname: Levine
authors.affiliation: Department of Community Mental Health,Faculty of Social Welfare and Health Sciences,University of Haifa,Haifa,Israel.
authors.forename: I
authors.initials: I
authors.lastname: Levav
authors.affiliation: Department of Statistics,Faculty of Social Sciences,University of Haifa,Haifa,Israel.
authors.forename: Y
authors.initials: Y
authors.lastname: Goldberg
authors.affiliation: Department of Information and Evaluation,Ministry of Health,Jerusalem,Israel.
authors.forename: I
authors.initials: I
authors.lastname: Pugachova
authors.affiliation: Department of Information and Evaluation,Ministry of Health,Jerusalem,Israel.
authors.forename: Y
authors.initials: Y
authors.lastname: Becher
authors.affiliation: Department of Information and Evaluation,Ministry of Health,Jerusalem,Israel.
authors.forename: R
authors.initials: R
authors.lastname: Yoffe
mesh_terms: D000328:Adult; D000069586:Adult Survivors of Child Adverse Events / Q000523:psychology / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D004641:Emigration and Immigration; D005060:Europe / Q000208:ethnology; D000069581:Exposure to Violence / Q000523:psychology / Q000706:statistics & numerical data*; D005260:Female; D063365:Genocide / Q000523:psychology / Q000706:statistics & numerical data*; D017767:Holocaust / Q000523:psychology / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D007557:Israel / Q000453:epidemiology; D008875:Middle Aged; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000523:psychology; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology*
keywords: Fetal origins; holocaust; malnutrition; refugees; schizophrenia