PRENATAL EXPOSURE TO MATERNAL STRESS AND SUBSEQUENT SCHIZOPHRENIA - THE MAY 1940 INVASION OF THE NETHERLANDS

Background It has been suggested that prenatal exposure to maternal st ress increases the risk of subsequently developing schizophrenia. Meth od The five-day invasion and defeat of The Netherlands by the German a rmy in May 1940 constituted a severe, well-circumscribed national stre ssful event. Individuals exposed and nonexposed to this stressor in th e first, second and third trimester of pregnancy were followed up for lifetime schizophrenia outcome through the National Psychiatric Case R egister. Register Cumulative incidence of schizophrenia was higher in the exposed cohort (risk ratio (RR): 1.15, 95% CI: 1.03-1.28), especia lly in those exposed in the first trimester (RR: 1.28, 95% CI: 1.07-1. 53). Significant interaction with gender was apparent in second trimes ter exposed cohorts (RR men: 1.35, 95% CI: 1.05-1.74; RR women: 0.83, 95% CI: 0.6-1.12). Conclusion Maternal stress during pregnancy may con tribute to the development of vulnerability to schizophrenia. The appa rent longer window of exposure in male foetuses may be related to the slower pace of male early cerebral development.