Do you ever wonder how your parents, grandparents, or ancestors endured traumatic events? Your DNA might have the answers. Researchers have debated the possible biological underpinning of intergenerational trauma when answering the complex question, “Does trauma end at the initial victim?”

 Intergenerational trauma occurs when trauma experienced in one generation affects the health and well-being of genetically related future generations. These epigenetic changes don’t involve alterations of DNA sequences but can affect how the genes are read by cells. Many scientific studies have examined the psychological trauma endured by victims of traumatic historical events. Trauma researchers are beginning to delve deeper into the impact of intergenerational trauma and its genetic expression. Some prominent human studies have included the Dutch Famine, the Rwandan Genocide, and the Holocaust. However, not everyone in the scientific community is convinced due to the remaining questions about its mechanism.

 The Dutch Famine case studied pregnant women subjected to famine in the Netherlands. These studies found their children carried a specific chemical marker, or an “epigenetic signature,” on one gene, and years later, when the cohort was studied again, differences in other genes as well. Researchers later linked this signature to poorer long-term health. The study on the Rwandan Genocide observed levels of distress in exposed mothers and offspring that were driven by the same symptoms. A following study led by the same research team also showed chemical markers on genes previously implicated in risk for mental illnesses such as post-traumatic stress disorder (PTSD) and depression. Although different from the genes identified in the Rwandan Genocide findings, the Holocaust study also showed the inheritance of a chemical marker on a specific gene linked to PTSD and depression.  

 Genetic, ecological, and cultural inheritance complexify the study of epigenetics. Social and environmental conditions can vary greatly across generations of the same family as well as among different families with parents who experienced similar trauma. Parental influence also varies, with some children raised with stories while others are never aware of the parental trauma during adolescence. Although there have been highly reproducible intergenerational and transgenerational inheritance cases in several model organisms, there remains a controversial debate about this phenomenon within the human epigenome. Psychotherapist and co-founder of the Group Project for Holocaust Survivors and Their Children in New York, Yael Danieli, believes “continuing to explore intergenerational effects can help the field better understand and treat psychological pain at its roots.” Many researchers continue to study its effects in the hopes that uncovering this young field of genetics could change the way we support victims and their future generations to lead healthier lives.

References

1. DeAngelis T. The legacy of trauma. American Psychological Association. https://www.apa.org/monitor/2019/02/legacy-trauma. Published February 2019.
2. Carey B. Can We Really Inherit Trauma? The New York Times. Published December 10, 2018. https://www.nytimes.com/2018/12/10/health/mind-epigenetics-genes.html#:~:text=The%20findings%2C%20the%20authors%20concluded,the%20gene%3B%20there’s%20no%20mutation.
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4. Musanabaganwa C, Wani AH, Donglasan J, et al. Leukocyte methylomic imprints of exposure to the genocide against the Tutsi in Rwanda: a pilot epigenome-wide analysis. Epigenomics. 2022;14(1):11-25. doi:10.2217/epi-2021-0310
5. Rudahindwa S, Mutesa L, Rutembesa E, et al. Transgenerational effects of the genocide against the Tutsi in Rwanda: A post-traumatic stress disorder symptom domain analysis. AAS Open Research. 2020;1:10. doi:10.12688/aasopenres.12848.2
6. Sangalang CC, Vang C. Intergenerational Trauma in Refugee Families: A Systematic Review. J Immigr Minor Health. 2017;19(3):745-754. doi:10.1007/s10903-016-0499-7
7. Yehuda R, Lehrner A, Bierer LM. The public reception of putative epigenetic mechanisms in the transgenerational effects of trauma. Environ Epigenet. 2018;4(2):dvy018. doi:10.1093/eep/dvy018

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