By: Analeah Rosen
It is well known that survivors of severe trauma have physical and emotional scarring – PTSD has been formally recorded and studied since the Civil War and has in recent years been used as a medical diagnosis thanks in part to the efforts of Holocaust survivor advocacy groups. And today, the research on PTSD continues to yield new insights. Dr. Rachel Yehuda the director of the Traumatic Stress Studies Division at the Mount Sinai School of Medicine in New York City and her colleagues have long studied the biological roots of trauma. Their most recent study has begun to show links between how trauma alters gene expression in survivors and how it might be passed down to their descendants. This effect of inherited trauma is commonly referred to as Transgenerational Transmission of Trauma (TTT).
The science behind PTSD and other trauma-related illnesses is in part related to cortisol – the hormone responsible for influencing and regulating stress. Dr. Yehuda and her colleagues have previously established that Holocaust survivors have lowered levels of cortisol as well as lowered levels of the enzyme responsible for breaking it down. According to Scientific American, “reducing enzyme activity keeps more free cortisol in the body, which allows the liver and kidneys to maximize stores of glucose and metabolic fuels—an optimal response to prolonged starvation and other threats.” Dr. Yehuda and her colleagues have discovered that the offspring of survivors also have lowered levels of cortisol.
These epigenetic changes – or, alterations to the expression of gene, but not the underlying DNA sequence – are thought to help prepare offspring to survive in an environment similar to their parents. Descendants of trauma have low levels of cortisol – however, unlike their parents they have high levels of the enzyme that breaks down cortisol and because of this, researchers believe that they are in fact more susceptible to PTSD and other cortisol-related disorders. And cortisol effects more than just stress, it is responsible for regulating insulin, immune responses, anti-inflammatory actions and blood pressure. One of the most important insights of Dr. Yehuda’s research is that PTSD continues to have profound impacts on the physical health of survivors long after the traumatic event has ended.
The development of the Transgenerational Transmission of Trauma theory has also led researchers to begin investigating the possibility for survivors of sexual abuse and human trafficking to pass on trauma to their descendants. These survivors often exhibit the same intensity of PTSD and other trauma-related illnesses well after they have been moved to safety. So while the research on TTT is still in the developmental stage of proving that trauma can be genetically passed through generations, there is one common thread: trauma has lasting effects on the emotional and physical health of survivors, their children and grandchildren, and their communities.