Can Trauma Really Be Passed Down to Future Generations Through Epigenetics?
Evidence is pointing that way, but it's not all bad news
Hiya!
When we think of what we inherit genetically from our parents, traits like our smile or hair may come to mind first. Or perhaps our laugh or stubbornness. But what if we also took on their traumatic experiences? What if our children inherit them too, along with our own? Would we pay more attention to the experiences we have? What about how we treat each other?
For the last few decades, experts have wondered about this too. While still experimental and more research is needed, the evidence we have so far shows intergenerational trauma is something we might want to start paying attention to. But there is some good news, intergenerational trauma appears to be reversible. Plus, traumatic experiences aren’t the only ones passed down — positive ones are too.
What is Epigenetics?
We all know the notorious Nature vs. Nurture debate. Thankfully, I think most people can agree that it’s not one or the other. Both our genes and our environments impact who we become. The nature side regards our DNA, the traits and health conditions that are genetically passed down to us from our family lines, which in turn impacts who we become.
Genetics, like eye color, decide which proteins are made, while epigenetics chooses which proteins are activated. For instance, my mom has blue eyes, and my dad had brown eyes, but I also inherited a gene for green eyes from my paternal grandma. These are my genetics, and they created proteins for each color. Then my epigenetics instructed my green gene protein to “turn on” while telling my proteins for blue or brown eyes to “turn off.” As a result, I have green eyes.
However, not all types of epigenetics are irreversible the way eye color is. Some of them change throughout our entire lives. The ones we have at birth are different from those we have as adults.
Because when we change our habits — like picking up smoking or committing to an exercise routine — we also change our gene expression, which determines when and how often our genes instruct proteins to be made.
So in a way, epigenetics bridges the divide between Nature and Nurture. Regarding nature, epigenetics play a role in activating genetic proteins while also doing the same for our gene expression based on the Nurture side of the discussion. The Center for Disease Control (CDC) summarizes epigenetics nicely.
“Epigenetics is the study of how your behaviors and environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence.”
Embryologist Conrad Waddington coined the term “epigenetics” after the 17th-century concept of “epigenesis.” He introduced the theory in 1942, and scientists worldwide have enthusiastically explored the idea ever since. In the process, some experts noticed a bewildering possibility — intergenerational trauma.
Intergenerational Trauma
The theory goes that because a person’s genes become epigenetically altered when they’re traumatized, these genes can then be passed down to future generations. The idea of intergenerational trauma may have been laughed at before, and there are still some skeptics, but evidence over the last 20 years is piling up. At the time of writing this, Google Scholar has about 59,000 papers related to it in just the last decade.
It’s clear the theory is becoming widely accepted. That our experiences may, in fact, alter our children’s and even grandchildren’s cells and, in turn, their behaviors. In an article by Science, epigenetics researcher Michael Meaney at McGill University in Montreal, Canada, states,
"If you're asking, ‘Does the experience of the parent influence the process of development?' the answer is yes,"
Dr. Meaney’s studies show that “differences in maternal care can have epigenetic effects on brain development.” And he’s not alone. However, most of the supporting evidence comes from research done on mice.
The same Science article discusses several studies focused on mice and other organisms like water fleas. The offspring of the water fleas that were exposed to the scent of a predator was born with “spiky, armored heads.” Talk about a dramatic response.
Time, and time again, traumatic gene expression was passed down to future generations. Apparently, the trauma trait was passed down for over 80 generations in a type of worm called Caenorhabditis elegans.
Human Studies
But, there are some studies that focus on humans. Particuarly the children of Holocaust survivors and veterans. All of which indicate the existence of intergenerational trauma.
For instance, in one from 2011, clinical psychologist Natan P.F. Kellermann, AMCHA, investigated “the prospect of inheriting the nightmares from our parent’s subconscious.” He wanted to know if children inherit Post Traumatic Stress Disorder (PTSD) from their parent’s experiences in the form of nightmares.
Dr. Kellermann learned that many children of Holocaust survivors suffer from nightmares. During them, they report being “chased, persecuted, tortured or annihilated as if they were re-living the Second World War repeatedly.”
By the end of the study, he proposes,
“The general sensitivities of the unconscious of our parents may be inherited through the epigenome, and that it has a continual powerful effect on us.”
Unfortunately, nightmares aren’t the only way an offspring might experience their parent’s or grandparent’s experiences. Some believe intergenerational trauma may present as a somewhat typical trauma response, minus any flashbacks. Since the person suffering from them isn’t the one who actually experienced the event(s).
However, there are still too many variables to know for sure. While convincing, for now, intergenerational trauma remains a theory. This is primarily because most of the information we’ve gained so far is based on animals. Applying it to humans complicates things because we don’t have a way to filter what we inherit from what we personally experience.
Implications of Intergenerational Trauma
If intergenerational trauma proves true, the implications are literally life-changing. Biologist Michael Skinner told Science,
"This is really scary stuff. If what your grandmother and grandfather were exposed to is going to change your disease risk, the things we're doing today that we thought were erased are affecting our great-great-grandchildren."
Talk about pressure.
We already know that unresolved traumatic experiences of a parent can reverberate to future generations in the form of “continuing the cycle,” often in the forms of addiction or abuse. This form of continuation relates to the Nurture side since its impact stems primarily from a person’s environment via their upbringing.
But intergenerational trauma adds another, deeper layer of influence by inheriting previous generations’ traits, making it that much harder to “break the cycle.”
Additionally, outside of the personal impact, how might society react? If taken to an extreme, this could become an effective argument against everything from harsher penalties for offenders of violence to micro-managing a woman’s behavior while pregnant. Would our cultures finally place more emphasis on the importance of mental health?
Can We Heal Intergenerational Trauma?
Remember, if the epigenetics of intergenerational trauma isn’t genetic, it means we aren’t completely doomed.
Isabelle Mansuy, a professor in neuroepigenetics in the Medical Faculty of the University of Zurich and the Department of Health Science and Technology of the Swiss Federal Institute of Technology Zurich, has extensively studied the effects of intergenerational trauma in mice. The Science article discusses her experiments in length, but one, in particular, stood out to me.
In 2016, Mansuy published evidence that intergenerational trauma can be reversed. Further, it’s not limited to traumatic experiences. Positive ones also seem to pass down epigenetically. Mansuy discovered that when traumatized mice were raised in a positive environment, it broke the cycle, and they didn’t pass along traumatic symptoms to their offspring.
It was a small study and will require more data before they can say for sure, but Mansuy is working on an expanded version. Still, it’s a promising start. While still a theory, many researchers are nearly convinced. Much of my research in this article states the same advice for anyone who thinks they inherited intergenerational trauma from their parents.
Namely to seek care from professionals who focus on trauma healing. Even if you don’t have personal memories of the event, they can still help your body’s physiological response.
On the bright side, it appears to go both ways. Positive life experiences and healing also impact us molecularly. If it holds true, then this is fantastic news because while we may inherit some trauma from our parents and grandparents, we can also inherit — or heal and then pass down — the positive ones. Talk about an incentive to collect as many loving, exciting, and safe experiences as possible.
On a larger scale, could we redesign society into a more sustainable one where people feel safe? Would it be enough to heal an entire generation?
Perspective Shift
Brilliant minds continue to learn more, but even still, the idea is mind-blowing. It means we just might inherit much more from our parents than our looks and traits. But also their experiences. In turn, our experiences, good or bad, are potentially passed down to our children, and their children.
Unlike our genetic factors, which we can’t change even if we wish to, these epigenetically transferred behaviors are within our power to reverse. We have the choice to heal and overcome.
Beyond an individual level, how might this knowledge alter society? Would we be kinder? More humane to each other? Maybe, for once, violence and rage could take a back seat in how we express our issues. Perhaps, like Mansuy’s mice, we can create a positive environment within society and heal entire generations at once. Who knows. But gosh, it’s fun to think about.
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