Children born to mothers who were older than five at the start of Nazi persecution face a more than two-fold increase in the risk of developing schizophrenia. A new study, published in the American Journal of Psychiatry, analyzed data from the Jerusalem Perinatal Study to track the long-term, intergenerational impacts of severe preconception trauma.
The shadows of historical atrocities can extend across generations, influencing the mental health of offspring born decades after the initial trauma. New research led by the Hebrew University of Jerusalem indicates that severe preconception trauma experienced by mothers can fundamentally alter the psychiatric vulnerability of their children. The findings suggest that the timing of exposure during childhood is a critical factor in this intergenerational transmission.
Defining the Five-Year Threshold
To investigate these effects, researchers utilized data from the Jerusalem Perinatal Study, a cohort that tracked births in West Jerusalem between 1964 and 1976. By linking these records to Israel’s National Psychiatric Registry, the team monitored hospitalizations for schizophrenia and related disorders through December 2004. The analysis included 14,759 children of tracked mothers and 18,085 children of tracked fathers.
The study classified parents as “exposed” if they were of Jewish ancestry, born in European countries under Nazi rule, and immigrated to Israel after persecutions commenced. These parents were further divided into two groups: those who were five years old or younger when persecution began, and those older than five. The researchers found a stark disparity in outcomes based on this age cutoff.
“The decision to use age 5 as the cutoff wasn’t arbitrary. It was based on two considerations. First, from a developmental psychology perspective, age 5 is when exposure to events and perception of reality become more significant. Second, there was a statistical consideration. Setting the cutoff at an older age would have significantly reduced the number of mothers and fathers eligible for the study.”
Hagit Hochner, Hebrew University of Jerusalem
Children of mothers who were older than five during the initiation of Nazi rule remained 2.38 times more likely to develop schizophrenia, even after adjusting for factors such as socioeconomic status, birth weight, and the mother’s own psychiatric history. Conversely, no elevated risk was detected in offspring whose parents were five or younger at the start of the persecution. Researchers hypothesize that very young children may have been shielded by primary caregivers or possessed cognitive faculties that limited their perception of the ambient danger.
Maternal Transmission and Biological Pathways
The study highlights a significant disconnect between maternal and paternal trauma transmission. While initial observations suggested an elevated risk among the children of heavily traumatized fathers, this association became statistically non-significant once researchers controlled for sociodemographic variables. The enduring strength of the maternal connection suggests that trauma may be transmitted through distinct biological and environmental pathways.
The researchers noted that maternal trauma could impact future generations through the intrauterine environment during pregnancy, greater engagement in early childhood parenting, or epigenetic alterations in the germline. This preconception echo
serves as a warning for modern public health, particularly as global conflicts continue to displace populations.
“Understanding how trauma experienced even before conception affects later generations can help us anticipate the long-term health consequences of wars. Given the growing number of wars and conflicts – including in our own region – we have a professional responsibility to investigate these effects.”
Hagit Hochner, Hebrew University of Jerusalem
Comparing Risks in Modern Clinical Contexts
The study’s focus on intergenerational trauma arrives alongside other recent findings regarding schizophrenia risk factors. Together, these findings underscore the multifaceted nature of schizophrenia, a condition that affects approximately 25 million people globally.
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