When I was a kid I discovered my family's ancestry book, dating as far back as the 1700s. My grandparents kept it stowed away, preferring not to discuss its contents. It wasn't until my twenties that I discovered why.
As it turns out, both my grandmother’s and grandfather’s parents were Volga Germans who immigrated from Russia to America in the early 1900s. Over many centuries leading up to this, my ancestors survived political chaos, religious strife, and economic hardship in the Kingdom of Prussia, followed by violent uprisings, Russification, and genocide in their villages along the Volga river.
It’s no wonder my grandparents avoided sharing our ancestry book with my mother, and with me and the rest of their grandchildren. There was no sense in rehashing old traumas. For the sake of their descendants, the book was closed so that we could move forward.
I always thought of myself as a strong person. But after I was strangled by someone I thought I knew, I struggled to emerge from post traumatic stress disorder. There I was, looking over my shoulder in the halls of my home, and afraid to relive the experience in yet another night terror. Trauma changed me on a cellular level. How must my ancestors have felt?
Maybe PTSD, like hair color, is something we share in common.
According to Harvard Medical School, “Research evidence clearly suggests a predisposition or susceptibility for developing PTSD that is hereditary in nature, with 30% of PTSD cases explained by genetics alone.”
To make sense of this, we look to epigenetics: the study of how gene expression is changed by environmental factors. Whereas the human genome is the complete assembly of a person’s unique DNA, the epigenome is comprised of chemical compounds and proteins that attach to DNA and can silence genes, activate them, or modify their function.
Heritable epigenetic modifications can be spurred by exposure to stress or traumatic events along with environmental or lifestyle factors such as drinking and smoking, exercise, or drug use. Although epigenomes usually reset with each new generation, modifications can be passed down from one generation to the next. This doesn’t guarantee that a descendant will develop the same, stress-related physical or psychological ailments of their ancestors, but it does increase their vulnerability.
Trauma, stress, and prolonged activation of the body’s fight-or-flight response have a pervasive effect on the body. When faced with intensely stressful situations, our bodies produce an onslaught of stress hormones called glucocorticoids, which modify genetic expression in the brain. A growing body of research reveals just how much those modifications can be inherited. In fact, scientists have observed epigenetic memories being passed down for fourteen generations.
Not everyone who experiences a traumatic event walks away with PTSD. A 2001 study by Bresalu and Kessler determined that an estimated 75% of the population experiences a traumatic event, and yet only a fraction of those individuals develop PTSD. This would suggest that PTSD is influenced, at least in part, by a genetic predisposition to it. Several family studies have demonstrated this finding, most notably one study led by Rachel Yehuda of Holocaust survivors and their descendants.
In her previous studies on the stress hormone profiles of Holocaust survivors, Yehuda established that survivors with PTSD had markedly lower cortisol levels than their non-trauma affected peers. These survivors also exhibited the lowest levels of an enzyme that breaks down cortisol. As explained by Scientific American, “The adaptation makes sense: 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.”
In order to find out if Holocaust survivors pass down their stress hormone profiles to their children, Yehuda and colleagues gathered a group of adult children of Holocaust survivors and tested their cortisol and enzyme levels as well. Like their parents, the descendants had significantly lower levels of cortisol; but unlike their parents, they had much higher enzyme levels than normal.
A potential theory for the adult children’s heightened enzyme levels possibly begins in utero. Yehuda speculates that when a mother with low levels of the cortisol-destroying enzyme becomes pregnant, a greater level of enzymes flood the fetus to protect it from circulating cortisol. Although this adaptation serves to protect the fetus from stress hormones in utero, once the child is born, their low cortisol levels and high enzyme levels render them more susceptible to developing PTSD.
These theories, like other similar models, explain how children who have not themselves been traumatized tend to manifest inherited emotional problems. Prolonged activation of the fight-or-flight response causes debilitating and often irreversible damage. As is the case with PTSD, epigenetic modifications play a role in the development of other stress-related disorders, like generalized anxiety disorder and obsessive compulsive disorder.
Furthermore, women who survive long-term abusive relationships frequently report chronic pain and physical ailments in addition to anxiety, depression, and PTSD. One of the most commonly reported of those is fibromyalgia. Research suggests that genetic factors are responsible for up to 50% of fibromyalgia susceptibility, and that individuals who were genetically predisposed to the syndrome are at an increased risk of developing it.
Can ancestral trauma be healed?
While more research needs to be done to determine the full breadth of heritable epigenetic modifications, it is increasingly clear that ancestral exposure to trauma can be highly detrimental to future generations. Without a detailed ancestry book or concrete records of family trauma, questions of how to identify ancestral trauma and how to proceed in healing it remain.
For those who are suffering from depression, PTSD, anxiety, fibromyalgia, or any other disorder with stress at its foundation, the first place to start is by determining whether or not you are genetically predisposed to it. This can be as simple as talking with relatives. Or, you may consider consulting with a specialist who can conduct epigenetic tests on DMRs (differentially methylated regions)- the gene regions where epigenetic changes are observed.
With the right approach, epigenetic predispositions to PTSD may be reversible for both the person immediately affected by the disorder and their future descendants. A multinational research study of veterans with PTSD found that both trauma-focused cognitive behavioral therapy (tf-CBT) and eye movement desensitization processing (EDMR) are effective in reducing the symptoms of PTSD along with its epigenetic effect.
Different patients observe different symptoms, so while some patients may seek treatment through psychotherapy or holistic healing, others may consider acupuncture, cranial sacral healing, or another form of meditation. It’s important to remember that although ancestral exposure to trauma may increase susceptibility, genetics don’t always play a role in a certain disorder’s development. Ultimately, to liberate future generations, we must strive to clear ourselves of stress wherever possible, and heal the imprint of trauma in our own lives.