New Leaves on the Tree: How Trauma Affects Inheritable Gene Expression

Lafleche Jeannette Giasson

doi:10.7191/gmr.1066

Context

According to the World Health Organization, anxiety disorders are the most common of all mental disorders, affecting 4% of the global population, or 301 million people in 2019 (Sept. 2023). Depression disorders are also extremely common, affecting 3.8% of the global population, or 280 million people (World Health Organization, Mar. 2023). Anxiety and depression are commonly experienced together, and though both result from “a complex interaction of social, psychological, and biological factors,” and anyone can have these disorders, people who have lived through abuse, traumatic events, and other adverse life events are more likely to develop them (Sept. 2023).

Trauma can stem from war and violence, grief and loss, abuse or neglect including physical, emotional, and sexual abuse, natural disasters, medical intervention, and cultural and historical trauma. According to the National Council for Community Behavioral Healthcare, 70% of U.S. adults have experienced a traumatic event at least once, and 20% who experience a traumatic event will develop Post Traumatic Stress Disorder (PTSD) (Zauderer, 2023). In 2023, most people know what PTSD is and are familiar with its symptoms, such as anxiety, depression, flashbacks, and recurring intrusive memories or nightmares, trouble sleeping, being easily startled, an exaggerated fight-or-flight response, shame, irritability, and detachment. People who experience a major or violent traumatic event will likely be able to trace their PTSD symptoms to the event. However, others may experience similar symptoms without having experienced such an event. This comic seeks to offer a possible explanation to people who suffer PTSD symptoms whether or not they feel they deserve to, to validate their experiences, and to possibly offer the resolution that follows understanding.

Firstly, though most people have heard of PTSD, many may not be familiar with its lesser-known counterpart, ComplexPTSD (cPTSD). While PTSD occurs after a single traumatic event triggers a fight-or-flight response so intense that the person can no longer turn it off, cPTSD develops from chronic trauma, even at less intense levels. ComplexPTSD can result from extended periods of verbal, mental, emotional or psychological abuse, extended periods of physical or sexual abuse, or even just emotional neglect (Walker, 2013). While some of these, such as physical abuse, will be easier to identify as abuse, others such as emotional neglect may feel “normal” to the victim who experienced it as a child, and these people will often fail to recognize their cPTSD symptoms for what they are. cPTSD symptoms include depression, anxiety, suicidality, radical mood vacillations, social anxiety, inhibition to seek help or connection, attachment disorders, an exaggerated fight-or-flight response, being easily startled, oversensitivity to stressful situations, developmental arrests, and emotional flashbacks.

People who experience the symptoms of PTSD and cPTSD are the intended audience of this comic, and the author offers it with empathy as an exploration of the potential origins of these symptoms. Although many readers with cPTSD may trace the origin of this disorder to their childhoods and the way they were treated by their parents, I encourage readers to understand their parents as survivors of experienced and/or inherited trauma also. What people teach their children about how to value themselves, how to build relationships, where to expect danger, how to interact with the world, and so on, is based on what they’ve learned and on their ability to parent, both of which can often be affected by their own mental health. Furthermore, research studies in epigenetics reveal trauma and stress affect inheritable gene expression, which means that trauma suffered by one generation can affect the succeeding generations on even a biological level. This is the premise of research psychologist Mark Wolynn’s 2017 book It Didn’t Start with You: How Inherited Family Trauma Shapes Who We Are and How to End the Cycle, which I use as a central framework for this comic. Your trauma didn’t start with you, and it most likely did not start with your parents either.

Epigenetics is the study of heritable gene function that occurs without a change in the sequence of DNA. Chromosomal DNA, responsible for physical traits like hair color and eye color makes up just 2% of our DNA, whereas non-Coding DNA (ncDNA), responsible for emotional behavioral, and personality traits, make up 98%. ncDNA is known to be affected by environmental stressors like toxins, inadequate nutrition, and big emotions like stress, shame, and fear (Wolynn, 2017, p. 29). These stressors will trigger epigenetic tags, or chemical signals that attach to DNA to either silence or activate a gene, altering its expression. These tags will be passed along with the DNA, and they will affect the DNA of the fetus in a pregnant mother, as well as the precursor sperm or egg cells in that fetus. This applies also to the egg cells present in the body of a female who is not pregnant, all of which are present in her body from 5 months of her inception. Similarly, the precursor sperm cells that will become the next generation are present in a man’s body when he is affected by environmental stressors, and epigenetic changes in his DNA occur in these cells as well (Wolymm, 2017, pp. 25-26). In the sense that we shared a biological environment with our parents when we were sperm, egg, and precursor cells in their bodies, and with our grandmothers when they were pregnant with our mothers, we were “present” for and directly affected by the trauma they experienced, and the epigenetic tags in our DNA can be passed to our children also, who were not.

Rachel Yehuda, a leading expert in PTSD and epigenetics, conducted with her research team a number of studies that found that children with mothers with PTSD had genes that expressed differently from those whose mothers had not (Wolynn, 2017, p. 31). According to Yehuda, the function of these epigenetic tags is to biologically prepare us to cope with what our parents went through by giving us the traits we would need for that environment. This “environmental resilience” is on the one hand helpful in aiding us to maneuver stressful situations, but on the other hand destructive if there is a mismatch between biological readiness and actual environment (Wolynn, 2017, p. 30). For example, an epigenetic tag causing a heightened or more sensitive startle response is helpful in emergency situations, but in day-to-day life it could result in chronic stress, which can lead to weight gain, fatigue, acne, irritability, headaches, difficulty concentrating, and more. Increased amounts of epigenetic tags activating genes that trigger cells to release stress hormones have been found in people with depression and anxiety. Not only do these things negatively impact current well-being, they may also predispose someone to stress disorders and disease later in life.

Conclusion

Stress and mood disorders negatively impact health and well-being, and these disorders may be due in part to inherited gene expression; the positive counterpart to this information is that positive emotions like hope, love, and serenity are as powerful as negative emotions like stress, fear and shame. It is possible and beneficial to seek to resolve fears that originated in our pasts so that we may stop living with them as though they belong in the present. Letting go of negative emotions that we either harbor for our parents or that were passed down to us by our parents, and instead intentionally focusing our attention repeatedly on thoughts of love and well-being can create new neural pathways, deactivate or silence epigenetic tags inherited from trauma suffered by our parents and ancestors, and reverse the effects of trauma on our gene expression.

Design Process

I delivered the research content of this comic within the context of an empathetic conversation between friends sitting in a city park and used the park environment to facilitate visual metaphors during their conversation; for example, providing an image of a family of geese when talking about parents, or of bird eggs in a nest when directing the narrative to a time before we are born. To draw this 16-page comic meant to efficiently cover a lot of information as effectively as possible, I used a visually clear drawing style with clean black ink lines and selective black color blocking, and colored it with a limited palette of muted blue and yellow tones. I chose these colors because I find the semi-complementary pairing of blue and yellow pleasing and muted them to keep the visual experience calm to match the tone of the conversation and to avoid overwhelming the reader, particularly when the content is complex and sensitive.