Summary: A new population-based study found that children born decades after World War II to mothers who were older than five years when Nazi persecutions began face a markedly higher risk of schizophrenia. The increase—more than twofold—persisted after accounting for birth weight, sociodemographic factors, and the mother’s psychiatric history, pointing to long-lasting intergenerational effects of severe early-life trauma.
Key Facts
- More than twofold increase in schizophrenia: Offspring of mothers who were older than five when Nazi persecutions started had a greater than twofold higher risk of schizophrenia. This association remained statistically strong after adjustments for relevant covariates.
- Age five as a critical threshold: No increased schizophrenia risk was detected among children whose parents were five years old or younger at the start of persecutions. Investigators suggest toddlers may have been buffered from extreme stress by caregivers or experienced the trauma differently at that developmental stage.
- Maternal transmission stronger than paternal: While initial analyses showed a smaller increase in risk for offspring of exposed fathers older than five, that association disappeared after adjusting for sociodemographic variables. The maternal effect remained robust.
- Potential biological pathways: The research highlights possible mechanisms including alterations to the maternal intrauterine environment and epigenetic changes in the female germline that could transmit vulnerability across generations.
- Public-health implications: The authors emphasize that large-scale violence and displacement can produce intergenerational mental-health burdens that persist for decades, underscoring the need for prevention and long-term support strategies.
Source: Hebrew University of Jerusalem
Overview
Researchers from the Hebrew University of Jerusalem and Mount Sinai investigated whether severe preconception trauma experienced by children during World War II affected psychiatric outcomes in their offspring. Using birth records and national psychiatric hospitalization data, the team examined whether the children of Holocaust survivors had an elevated risk of schizophrenia and whether that risk differed by parent, timing, and age at exposure.
Study design and data
The analysis used the Jerusalem Perinatal Study, which recorded births in West Jerusalem from 1964 to 1976, linked to Israel’s National Psychiatric Registry through 2004. Two offspring cohorts were evaluated separately: 14,759 children born to 7,316 tracked mothers and 18,085 children born to 8,833 tracked fathers. Parents were classified as “exposed” if they were Jewish, born in European countries under Nazi rule, and had immigrated to Israel after persecutions began. Exposed parents were divided by their age when persecutions started: five years or younger, or older than five. Unexposed parents were of European background not subject to those persecutions.
Key findings
Offspring of mothers who were older than five at the onset of Nazi persecutions faced a significantly elevated schizophrenia risk. In minimally adjusted models the maternal exposure hazard ratio was 2.71 (95% CI: 1.60–4.61). This effect persisted after adjustments for sociodemographic factors, birth weight, and the mother’s own psychiatric hospitalization history, with adjusted hazard ratios remaining above two.
By contrast, no elevated risk was observed among offspring of parents exposed at age five or younger. For fathers, an initial modest association in minimally adjusted models diminished and lost statistical significance after controlling for sociodemographic covariates, indicating a stronger and more persistent maternal-line effect.
Interpretation and mechanisms
The study supports the idea that timing and the sex of the exposed parent shape intergenerational psychiatric risk. Possible explanations include lasting epigenetic modifications in a female’s germline induced by severe childhood stress and changes to the maternal intrauterine environment during later pregnancies. Maternal caregiving patterns and early-life exposures that shape fetal development are also plausible contributors to transmission of risk.
The absence of increased risk when exposure occurred at age five or earlier suggests a developmental window during which severe stress is more likely to leave biological marks that affect future reproductive cells or later pregnancies. Alternatively, very young children may have been more extensively sheltered from traumatic events by caregivers, reducing the intensity of biological stress responses that can produce long-term changes.
Limitations
The authors note several limitations: the study could not measure individual subjective experiences of trauma, it was constrained to hospitalizations recorded through 2004 (so later-onset cases were not captured), and residual confounding is possible despite adjustments. Nonetheless, the large, population-based design strengthens confidence in the observed associations.
Public health message
Senior author Hagit Hochner and colleagues stress that trauma experienced before conception can carry consequences for descendants many decades later. As conflict, displacement, and large-scale violence continue in many regions, recognizing and addressing the long-term intergenerational impacts is important for planning mental health services and prevention strategies. Reducing violence and supporting affected populations are framed as urgent public-health priorities to limit enduring generational harm.
Frequently asked questions
A: Severe childhood stress can produce long-term biological changes. For girls, these changes may affect germline cells (eggs) or alter physiological systems that influence future pregnancies. Epigenetic modifications—molecular marks that alter gene expression without changing DNA sequence—are one plausible mechanism by which preconception trauma might increase psychiatric vulnerability in the next generation.
A: The study suggests two nonexclusive explanations: young children may have been heavily protected by caregivers, reducing the intensity of stress responses, and developmental differences in early childhood may make traumatic experiences less likely to produce persistent germline or biological changes that affect later offspring.
A: No. While a small association appeared for offspring of fathers exposed at older ages in unadjusted models, that link disappeared after accounting for sociodemographic factors. The persistent effect was observed predominantly through the maternal line.
Editorial notes
- This article was edited by a Neuroscience News editor.
- The original journal paper was reviewed in full.
- Additional contextual information was provided by editorial staff.
About this research
Author: Danae Marx
Source: Hebrew University of Jerusalem
Contact: Danae Marx – Hebrew University of Jerusalem
Image: Image credit noted by Neuroscience News
Original research: “Schizophrenia in Offspring of Holocaust Survivors: Intergenerational Effects of Preconception Parental Trauma Within the Jerusalem Perinatal Study” — authors include David S. Siscovick, Dolores Malaspina, Hagit Hochner, Iaroslav Youssim, Ilona Shapiro, Ora Paltiel, Orly Manor, Ronit Calderon-Margalit, Salomon Israel, and Yechiel Friedlander. Published in the American Journal of Psychiatry. DOI provided in the original publication.
Abstract
Objective: To evaluate whether parental preconception trauma experienced during the Holocaust is associated with increased schizophrenia risk among offspring born years later.
Methods: Birth records from the Jerusalem Perinatal Study (1964–1976) were linked to national psychiatric hospitalization data. Parents born in European countries under Nazi rule who immigrated after persecutions began were classified as exposed and categorized by age at exposure (≤5 or >5 years). Two offspring subsamples were analyzed using time-to-event models for first schizophrenia hospitalization.
Results: Offspring of mothers older than five at exposure showed elevated schizophrenia rates across multiple models, with associations that persisted after adjustment for sociodemographic variables and maternal psychiatric history. No association was observed for offspring of parents exposed at age five or younger. Paternal associations attenuated after covariate adjustment.
Conclusions: Maternal exposure to severe childhood trauma before conception—particularly when exposure occurred after age five—was associated with more than a twofold increase in schizophrenia risk for offspring, highlighting the importance of timing and parental sex in intergenerational effects of trauma.