Dr Tara-Lyn Camilleri studies epigenetics and the transgenerational effects of trauma.
Photo: SUPPLIED
Do we inherit the effects of trauma physically from past generations? Do parents’ experiences of war, ethnic persecution, cultural oppression, state or domestic abuse have lasting effects, manifested in their children?
There’s no doubt we can feel it, but can the trauma of previous generations actually be coded into the bodies of their children? New research is beginning to shed light on this.
Dr Tara-Lyn Camilleri, an Oxford scholar and now a researcher at Monash University in Melbourne, specialises in epigenetics – the interplay between our environments, lived experiences and how our genes are expressed. She talked to Mihingarangi Forbes about the biology and what that tells us about breaking cycles of transgenerational trauma.
In a wider sense, “transgenerational trauma is when the effects of trauma in one generation ripple into the next generation, so it can shape us in a few key ways – biologically socially psychologically and culturally” Camilleri says.
“So psychologically, if someone’s experienced trauma it can effect how they parent, how they regulate emotion, and how safe their environment is in general – all will shape a child’s development. Culturally trauma can disrupt people connection to culture, language, history, land, which can carry through generations if healing doesn’t happen. So all of these things are constantly interacting with one another to produce these outcomes.
“Biologically, stress can change how our bodies regulate things like hormones and immunity and those changes can be passed on sometimes through what we call epigenetic mechanisms – when we feel unsafe it can activate stress pathways in the body that alter how certain genes are expressed.”
Epigenetics is not changes to the DNA and genes itself, but changes to other biochemical tags that affect how DNA code is used, or to surrounding proteins.
“I’ve described it as the directors notes on a script – these notes may tell the actors which lines to emphasise or downplay, but they’re not changing the script itself,” Camilleri says.
For example, the fight or flight response is how the body continually responds to either real or perceived threats.
And “this is when we start to get into the realm of phenotypic plasticity – it’s a fundamental process in biology – it doesn’t get a lot of attention, but things like stress or diet, these environmental conditions, can change our bodies, they change our neuroplasticity – the change the neurons in our brain, and they can change a whole host of other things, and that can induce these epigenetic changes.”
Genetics itself could mean a predisposition to experiencing stress in particular ways, including physically. Epigenetics can then “act like a volume dial” turning up or down those genes effects, and can be influenced by our parents experiences or our early childhood experiences.
The effects of phenotypic plasticity can also be seen in the animal world, Camilleri says. For example what a honeybee is fed will determine if it becomes a worker or a queen.
Some of those phenotypic changes can then be passed on to descendants, for example the body of stickleback fish can change to make it more difficult for predators to eat them. And this result can sometimes last for many generations when it is then cued by environmental factors like nutrients and hormones that regulate those responses.
Camilleri says her own research with fruit flies found different nutrition and diet changes could result in different effects for different generations. One diet fed to both parents and their children resulted in the parents living longer but the offspring living shorter lives, whereas a different diet of more protein resulted in both grandmothers and granddaughters producing more offspring.
The science shows change is possible
The effects of transgenerational trauma can skip generations, and there are also actions we can take to mediate its effects, Camilleri says.
“It’s not always set in stone … when we look at this research we don’t see what we would call very predictable effects – it can change all the time. These epigenetic changes are what we call plastic, so they don’t necessarily have to be permanent, and they are changing all the time throughout our lifetime all of the time.
“So there are several things we can do to mediate it, to ensure that we might be able to break the cycle – but certainly even without intervention, our genetics are always talking to our environment. Our biology and our environment are always interacting with our social systems and our culture, so it’s such a complicated mix of things that it’s not always set in stone.”
Photo: (Pixabay Public Domain)
Studies have found that how much of a parents’ experiences result in factors affecting their children depends on which parent was affected, she says.
Including one landmark study of cortisol (a stress hormone) in the children of holocaust survivors with PTSD. It found the children of mothers who were holocaust survivors were more likely to have cortisol dysregulation that made it more difficult to calm down from a stress response, compared to children of fathers who were holocaust survivors.
“They are more predisposed to these baseline cortisol levels not being able to return to normal and keeping the body in … a more prolonged stress state.”
Research has also found that breaking the cycle is more successful when the onus does not just fall on the individual, she says.
“There are personal strategies. Obviously therapy, seeing a psychologist, building supportive relationships and learning to regulate our stress and emotion, it definitely helps and it’s definitely very valuable – and that is where the emphasis is now, in society, it’s sort of on the individual.
“And I think what is changing is that we’re realising that those personal strategies that we can do are most effective when other solutions address wider systems that people live in, so that means tackling the social, the economic and the environmental conditions that keep stress or inequity high… large-scale events, war, colonialisation.
“Supporting things like cultural-led healing, community-led things by the people. Especially for these wide large-scale events – the people who’ve experienced these they need to lead these. Those voices need to be heard and listened to, so that it restores this sense of connection and identity and acknowledgement. Because it’s about people feeling safe within the systems that they live in.
“So when we change things at those broader levels we can reduce the load on individuals, and create those conditions where those individual strategies will be more likely to effect recovery and therefore affect subsequent generations.”