Transgenerational effects of genocide exposure on the risk and course of schizophrenia: A population-based study

Background Hypotheses about the sequel of parental genocide exposures on the offspring's risk and course of schizophrenia remain untested. Aims To test hypotheses related to the transgenerational transmission of parental genocide exposure on the risk and course of schizophrenia. Methods Data were extracted from the National Population Register on all offspring (N = 51.233; born: 1948–1989) whose parents were born (1922 to 1945) in Nazi- dominated European nations. Both parents either immigrated before (indirect exposure: n = 1627, 3.2%) or after (direct exposure: n = 49.606, 96.8%) the Nazi era. Offspring subgroups were identified from the initial timing of parental exposure (e.g., likely in utero, combined in utero and postnatal, or postnatal). Schizophrenia disorders were ascertained (1950–2014) from the National Psychiatric Case Registry. Cox models were computed to compare the offspring groups with respect to the risk and the adverse course of schizophrenia, adjusting for confounders. Results The offspring rates on the risk and course of schizophrenia did not differ by parental affiliation to the direct and indirect exposure groups. Cox models showed that offspring subgroups with maternal Holocaust exposures in utero only (HR = 1.74, 1.13, 2.66) and combined in utero and postnatal (HR = 1.48, 1.05, 2.10); as well as paternal Holocaust exposures combined in utero and postnatal (HR = 1.48, 1.08, 2.05), and early postnatal (aged 1–2; HR = 1.49, 1.10, 2.00) had a significantly (P < 0.05) higher psychiatric re-hospitalization rate than the indirect group. Conclusions Transgenerational genocide exposure was unrelated to the risk of schizophrenia in the offspring, but was related to a course of deterioration during selected critical periods of early life.