Growing up, your great-grandfather was your hero. A prisoner of war camp survivor, he was exposed to appalling conditions, extreme overcrowding and the daily threat of death by starvation or illness. Despite the trauma he endured, he survived and returned home to start a family. His experiences changed him, however — his job prospects were lower, his health suffered and his life expectancy plummeted. Not long after he passed away, your grandfather began to experience similar effects despite being born after the war. Decades later, you've noticed these same difficulties echo in yourself and your father. It was almost as if the hardships your great-grandfather bore had been passed on and you find yourself wondering, can trauma be inherited?
The answer may surprise you. When we think of genetic conditions, things like sickle cell anemia, cystic fibrosis and Down syndrome usually come to mind. Genetic research has identified more than 4,000 diseases caused by gene mutations, which are passed on from either one or both parents. A relatively new area of study, epigenetics, is changing the way we view inherited disorders by adding trauma to the list. Epigenetics explores how changes occur as a result of gene expression, rather than through mutations or alterations of our DNA. This can translate to significant effects that influence the elements that make us who we are, such as our physiology, pathology and phenotypic traits such as hair color. Until recently, it was believed that genetic variations could only occur through changes or mutations in the genetic code, but epigenetics is challenging that assumption. Research is demonstrating that our experiences, particularly those that are traumatic, violent or distressing, may have a deep influence that affects us at the biological level, impacting the health and development of not only ourselves but our descendants as well.
A Brief Overview of Epigenetics
Epigenetics was first coined in 1942 by Dr. Conrad Waddington to describe the process by which a fertilized egg formed into a complex, functional being. Over the next few decades, the scope of epigenetics has evolved to include the mechanisms driving gene expression and patterns of inheritance. Today, epigenetics studies how gene expressions are modified, affecting the way they are read without changes to the underlying DNA sequence.
Inherited epigenetic changes were first seen in plants such as tomatoes, which were observed to pass on chemical tags that affect an important ripening gene. Recent research is now showing transgenerational epigenetic effects in mice and humans, with studies revealing that descendants of war veterans, Holocaust survivors and famine sufferers have higher mortality rates and exhibit other symptoms associated with trauma. The stress of these experiences is thought to initiate changes that influence gene expression, creating distinct epigenetic signatures that negatively impact life expectancy, mental health, behavior and more.
Epigenetics and Inherited Trauma
Trauma has a resounding effect in ways that aren't always visible. Those affected by trauma often experience depression and anxiety, unstable or poor relationships, higher mortality rates and increased vulnerability to violence and substance abuse. Epigenetics, however, is revealing that trauma has a long-lasting impact that changes more than just the psyches of those affected. Epigenetics is showing that trauma can alter the biological behavior of their cells in a way that can be passed on to future generations.
Researchers at UCLA published a study that examined the long-term effects of trauma on the sons of former prisoners of war (POW) during the American Civil War. Conditions in these prisons were miserable and the men there were subject to disease, starvation and high degrees of psychological stress as a result. After they returned home, they experienced poorer health, difficulty seeking employment and a shortened life span. In other words, they were noticeably affected by their traumatic experiences. The study examined the life expectancy of their sons and found that they, too, had higher mortality rates than the general population. It seemed as if their sons were also affected by the trauma they had experienced.
Similar studies found the same effects in the descendants of other trauma survivors. One well-known example can be seen in the Native American Lakota tribe, whose ancestors were subject to massacre, starvation, rape, displacement and more. Dr. Maria Yellow Horse Brave Heart, a leading expert in transgenerational trauma, describes how that trauma manifests today as self-sabotaging behavior, higher rates of depression, vulnerability to substance abuse and violence, and an elevated risk of cardiovascular disease. Current members of the Lakota tribe exhibit mortality rates from heart disease and suicide that are almost twice as high as the general population.
These findings have also been replicated in animal studies. Researchers in 2013 conditioned mice to associate the smell of cherry blossoms with fear, pain and trauma. Afterward, they bred these mice and found that their offspring were more anxious than other mice and had a higher sensitivity to the scent of cherry blossoms. Closer examination revealed epigenetic changes on the gene that encoded specific smell receptors which were not present in control mice, suggesting that sensitivity to that particular scent was inherited.
What's Happening at the Biological Level?
Inherited trauma and epigenetics are a complex subject. One of the best-studied mechanisms of epigenetic changes are chemical tags that affect DNA expression in a process known as methylation. When these chemical tags are added or removed, they mark particular genes and signal whether they should be switched on or off. If your DNA is an instruction manual that tells your cells how to function, methylation can be compared to a highlighter. Methylation tells your body which genes are important and which ones it can overlook. This impacts the way your DNA is interpreted, affecting certain traits or characteristics such as how you respond to stress. These tags help explain the adaptability of organisms, allowing them to adjust to changing conditions without permanently shifting their DNA structure.
It was previously thought that the chemical tags that modify genetic expression were reset during conception, but epigenetic phenomenon is showing us this isn't always the case. How epigenetic changes survive fertilization is unclear, but scientists believe a process called genomic imprinting helps to protect methylation at certain points in the genome. Other theories explore the role of RNA in the epigenetic inheritance of trauma, with strong evidence demonstrating a causal link between RNA molecules and behavior. Regardless of the exact mechanism, epigenetic research is demonstrating that the traumatic experiences of our ancestors may produce resounding effects that we carry with us throughout our lives.
The Father-Son Phenomenon
Interestingly, the epigenetics of inherited trauma appears to affect men more than women. In the UCLA study of American Civil War POWs, their daughters appeared immune to the effects of trauma and did not experience the same higher mortality rates. Other studies found that a father's diet can exert transgenerational effects on their sons and grandsons, particularly influencing their metabolism and appetite, but did not affect female descendants.
Researchers hypothesize this is due to an epigenetic effect on the male Y chromosome, known as the father-son phenomenon. One 2016 study found that DNA methylation patterns on the Y chromosome are more stable, which may translate into stronger epigenetic action. Other findings are consistent with this hypothesis. Research that examined the effects of food shortages in remote Swedish villages found that the consequences of improper nutrition were only transmitted down the male line of descendants, demonstrating that epigenetic trauma is more readily passed from fathers to their sons.
What are the Implications of Inherited Trauma?
Epigenetics and the science of inheritance is young, but the implications of passing on the consequences of our traumatic experiences to our children are enormous. If trauma is not just an experience that occurs and remains in the past, it would not only change the way we view trauma but would alter the very context of our experiences, our mental health and how our lives relate to the legacy of our ancestors. It is no small thing that viewing trauma in such a way helps to answer some of the unexplained mysteries of human resilience. Why do some children thrive and others don't? Why do certain groups of people experience higher mortality rates? Are we irrevocably bound to the past? The theory of inherited trauma can also help scientists, clinicians, mental health practitioners and other specialists reclassify genetic disorders and provide hope to a wide array of communities grappling with the baggage of the past.
Perhaps most significantly, the findings of epigenetics can improve preventative and post-exposure treatment methods for those who are vulnerable to or currently suffer from the manifestation of trauma. We can apply the knowledge of epigenetics to minimize or negate the effects of malnutrition or starvation, devise better treatment plans for PTSD and other mental health disorders, and increase access to medical care in affected populations. Knowing the long-term effects of trauma may also motivate us to take greater steps in preventing abuse, neglect, familial separation and other events known to trigger adverse epigenetic effects. Social policies that protect our communities while promoting affordable education, adequate and accessible healthcare, stress management and improved nutrition could help prevent epigenetic damage and inherited trauma before it occurs.
Treating Inherited Trauma and Epigenetic Damage
The thought that trauma could be passed down through generations can be frightening, but it doesn't have to elicit a sense of finality or inevitability. Research demonstrates that the effect can be undone through the process of desensitization. The studies involving mice show how, after they've been conditioned to fear the smell of cherry blossoms, new associations could be formed that unpair the scent from the concept of pain. When these mice were reexamined, researchers found that they had lost their "fearful" epigenetic signature. This is hopeful for generations of humans who may be affected by epigenetic trauma, suggesting that the effect could be reversed with compassionate mental health care.
Bruce McEwen, neuroendocrinologist and stress expert at Bruce Rockefeller University in New York, describes how epigenetic effects can be overcome through recovery and redirection, beginning a new trajectory that prompts compensatory changes to address inherited trauma. According to McEwen, regular exercise, intensive learning and antidepressants can help reverse epigenetic effects on the brain. Mindfulness techniques and cognitive behavioral therapy have also been promising, increasing the plasticity of the brain and establishing new neural pathways to heal trauma.
Trauma-Focused Care at The Guest House
The Guest House is one of the country's leading treatment centers specializing in trauma and addiction recovery. Lead by Judy Crane, an internationally recognized expert in healing trauma and PTSD, The Guest House provides the support and guidance needed to help men and women restore their mental and physical health by resolving deep-seated trauma and nurturing a positive therapeutic experience. Judy recognizes how unresolved trauma impacts the lives of those affected, manifesting as persistent addictions, destructive behavior, chronic mental health concerns and a lower quality of life. Understanding that the trauma of our ancestors could influence our well-being today sheds light on how our lives relate to our parents' and provides context that paves a new way forward. This allows us to develop more targeted treatments, employ the most effective modalities and explore how alternative and holistic therapies such as meditation, hypnosis and breathwork can heal these deep soul wounds.