In May 2007, psychoanalyst Billie Pivnick entered Hangar 17 at New York City’s John F. Kennedy Airport, a space housing more than 1,500 artifacts collected from the collapse of the World Trade Center’s twin towers. Over a five-year period, the JFK Hangar was populated by exhibition designers, curators and museum professionals with the ultimate aim of creating the National September 11 Memorial Museum, a place that Pivnick hoped would make the memory of September 11th “alive enough to feel the emotions and the reality of what went on, but not so alive that it’s unbearable.”
Pivnick’s aspiration for the National September 11 Memorial Museum’s reception speaks to the larger point of how trauma is sought to be memorialized, how collapse needs to be managed. Memorial museums serve as a physical space where trauma can be acknowledged, defined by walls that seemingly give pain boundaries. This allows us to manage our trauma at a specified time – moments intentionally set aside to remember. It’s implied that once gone from the confines of the museum, once the day of acknowledgement passes and another starts anew, the trauma too shall pass.
However, as Dr. Rachel Yehuda points out, some survivors of catastrophic loss cannot compartmentalize their trauma because these experiences have left them biologically vulnerable to stress. A reputed professor of Psychiatry and Neuroscience at the Mount Sinai School of Medicine in New York, Dr. Yehuda began her work studying traumatic stress in Vietnam War veterans with post-traumatic stress disorder (PTSD). She observed that combat veterans with PTSD exhibited lower levels of cortisol production compared to combat veterans without PTSD, or healthy controls. Considering cortisol is the body’s primary stress hormone, Dr. Yehuda’s work demonstrated a counter-intuitive finding.
Determined to recapitulate her unique findings of dysregulated cortisol production in a different cohort of mass trauma survivors, Dr. Yehuda focused her research on the stress hormone’s levels in survivors of Nazi concentration camps. In collaboration with the Mount Sinai School of Medicine, she established a first-of-its-kind clinic for Holocaust survivors to provide them with care akin to that received by other war veterans. In an interview for the podcast On Being, Yehuda recounts that following the establishment of the clinic, “What we found was that our phone did ring, but it was mostly children of Holocaust survivors who called us. And what we began to see quite clearly was that offspring were reporting that they had been affected by the Holocaust in many different kinds of ways, but in a very coherent and cohesive pattern.” The anecdotes of the effects of cataclysmic trauma experienced by offspring of Holocaust survivors spurred Dr. Yehuda’s research into an unforeseen direction: not only was she interested in examining the hormonal responses of Holocaust survivors, but she wanted to investigate those of their children as well.
At the time, there had been few empirical studies carried out to document trauma exposure and psychiatric disorder in the second generation of Holocaust Survivors. Dr. Yehuda’s initial studies confirmed that Holocaust survivors have altered levels of circulating cortisol compared with other Jewish adults of the same age. She then turned to look at the children of Holocaust survivors, investigating the prevalence of stress and exposure to trauma, along with current and lifetime PTSD and other psychiatric diagnoses between them and a control group of comparable demographics. The results showed that although both groups experienced a similar number of traumatic events, the children of Holocaust survivors had an increased vulnerability to PTSD and other psychiatric disorders compared to the control group. More specifically, maternal PTSD resulted in lower cortisol production in adult offspring of Holocaust survivors. The children in Dr. Yehuda’s studies were conceived after parents had directly witnessed the Holocaust, highlighting the idea that trauma-related changes to parental biology can result in accompanying changes to offspring biology, making the Holocaust survivor children vulnerable to these same conditions.
That environmental exposures can etch the genome and affect gene expression is a widely acknowledged dogma of developmental biology. Various environmental stimuli can initiate processes that can switch genes “on” or “off” without enacting changes to an individual’s DNA sequence, a phenomenon known as epigenetic modification. Although these epigenetic changes are heritable through mitosis, whether these same changes can be inherited transgenerationally – meiotically – is controversial. Studies using Caenorhabditis elegans, organisms that lack sophisticated nurture capacities found in humans, point to instances of transgenerational epigenetic inheritance. Recent work has noted that changes in environmental temperature are associated with altered methylation of histone H3 lysine 9 (H3K9me3), lasting at least 14 generations. The addition or removal of a methyl group from a specific site of DNA constitutes one example of an epigenetic change, and lends to the idea of transgenerational epigenetic memory in this species.
Dr. Yehuda’s pioneering work with Holocaust survivors and their offspring provided some of the first insights into the inheritance of trauma in humans. With the concordance of uniquely diminished stress hormone levels in both first- and second-generation Holocaust survivors, the team at Mount Sinai’s School of Medicine examined a specific gene associated with cortisol production, FKBP5, and its methylation patterns between groups.
Yehuda’s group revealed that a specific region of the FKBP5 gene showed epigenetic changes in both Holocaust-exposed survivors and their progeny, but in opposite ways. Holocaust survivors showed 10% higher methylation of FKBP5 than controls, while offspring of Holocaust survivors had a 7.7% reduction of methylation at the same site compared to control offspring. These imprints to the genome could not be found in control groups and their children, attributing the parent’s exposure to the Holocaust as the likely perpetrator of these changes. The findings revealed by Dr. Yehuda’s group were the first to identify a stress-related epigenetic alteration among both trauma-exposed parents and their children, revealing how trauma can have profound intergenerational impacts. However, these biological alterations are not neatly passed on between generations. As John Krystal, editor of the journal Biological Psychiatry puts it, “The observation that the [epigenetic] changes in parent and child are in opposing directions suggests that children of traumatized parents are not simply born with a PTSD-like biology. They may inherit traits that promote resilience as well as vulnerability.”
A singular moment of mass catastrophe, of significant trauma, can enact a myriad of changes to our biological repertoire. Dr. Yehuda effectively demonstrates this in her work with Nazi concentration camp survivors and their children through the investigation of their respective physiological changes to stress. While the thought of inherited responses to traumatic events may be paralyzing, Dr. Yehuda’s consideration of epigenetics in this phenomenon reminds us that the environment can transmit many kinds of changes to our genome, not solely detrimental ones. An expanded range of potential biological responses, granted by epigenetic modifications, is an empowering wisdom that the body bestows. While trauma and human response to it is undoubtedly complex, acknowledging that personal reactions to it are inherently diverse, and for some, neatly layered into ancestry, indeed may make the trauma less alive and more bearable, just as Pivnick had hoped.
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- Yehuda, R., Boisoneau, D., Lowy, M. T. & Giller, E. L. Dose-Response Changes in Plasma Cortisol and Lymphocyte Glucocorticoid Receptors Following Dexamethasone Administration in Combat Veterans With and Without Posttraumatic Stress Disorder. Arch. Gen. Psychiatry 52, 583–593 (1995).
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- Rachel Yehuda —How Trauma and Resilience Cross Generations On – Being (2015).
- Yehuda, R., Schmeidler, J., Wainberg, M., Binder-Brynes, K. & Duvdevani, T. Vulnerability to post-traumatic stress disorder in adult offspring of Holocaust survivors. Am. J. Psychiatry 155,1163–1171 (1998).
- Yehuda, R. et al. Low cortisol and risk for PTSD in adult offspring of holocaust survivors. Am. J. Psychiatry 157, 1252–1259 (2000).
- Yehuda, R. et al. Holocaust Exposure Induced Intergenerational Effects on FKBP5 Methylation. Biol. Psychiatry 80, 372–380 (2016).
Trauma’s Epigenetic Fingerprint Observed in Children of Holocaust Survivors. Available at: https://www.elsevier.com/about/press-releases/research-and-journals/traumas-epigenetic-fingerprint-observed-in-children-of-holocaust-survivors.