Trauma leaves a mark on our genes

| July 15, 2022

Freud once famously said that the child is the father of the man. However, even the good doctor probably never imagined just how true this statement would prove. Indeed, science is increasingly demonstrating that the child of trauma often bears many sons and daughters.

Traumatic experiences, the evidence suggests, don’t just change us for a time. Rather, they can leave seemingly indelible marks that endure across multiple generations. The stigmata of trauma are neither figurative nor behavioural, though. Instead, the alterations induced by trauma occur from the inside out, marking us on the genetic level even as they change us on the psychological and behavioural levels.

The Genetic Basis of PTSD and Other Mental Illnesses

The concept of mental illness “running” in one’s family has existed long before the advent of genetic testing or neuroimaging. It’s such a cultural commonplace that it’s a popular theme in everything from tragic melodrama to situation comedies.

The genetic basis of mental illness, though, is proving to be far more than a cultural mythos. A 2019 study found, for example, that post-traumatic stress disorder (PTSD) often has a genetic component. Researchers assert that these genetic features of PTSD may well explain why some victims of trauma go on to develop PTSD while others do not.

There is also robust evidence that PTSD is far from the only mental illness with a potential or proven genetic component. Conditions ranging from depression to bipolar disorder to schizophrenia, for example, have been shown to share similar genetic patterns.

This may, indeed, explain the enormous interest in home genetic test kits, such as 23andMe. Nevertheless, physicians and researchers urge consumers to use these home tests judiciously. Home genetic tests often do not and cannot capture the full complexity of the relationship between genetics and mental illness, a relationship that even the experts only imperfectly understand.

Clinicians and researchers alike advise consumers to discuss their home test results with their healthcare providers to explore how these data may contribute to a better understanding of any mental health risks you may be facing.

Traumatic Childhood Experiences and Gene Expression

The future of mental health isn’t entirely clear, as there is much that remains to be discovered regarding the genetic components of mental illness and how these intersect with environmental and situational factors. Nevertheless, a large and growing body of research is documenting the profound impact that childhood trauma has on gene expression.

Researchers have found, for instance, that persons with borderline personality disorder were 13 times more likely than the general population to have experienced childhood trauma.

Other studies have shown that adverse events in childhood result in significant brain changes even where no symptoms of mental illness, such as PTSD, are evident. This is important because it can enable trauma survivors and healthcare providers alike to identify risk factors for the development of mental illness even where classical symptoms may not be obvious.

Importantly, because the trauma-induced changes identified by researchers occur at the structural, functional, and epigenetic levels, it’s not only the individual who has experienced the trauma who is affected, but also their offspring.  Researchers attribute these heritable genetic changes to the influence of the brain’s neurochemical responses to traumatic events, such as the surge of stress hormones, including cortisol and adrenaline, in the face of fear, threat, and chronic anxiety.

Generational Trauma and PTSD

Given what is known about the connection between trauma, gene expression, and inherited mental illness, it is perhaps not difficult to understand how generational traumas can link to significantly higher rates of PTSD and other mental illnesses.

For example, research has shown that generational poverty is strongly linked to mental illness. In addition to the direct physical impacts of poverty relating to poor nutrition and lack of adequate healthcare, the evidence suggests that the chronic anxiety associated with severe financial strain may result in genetic alterations associated with trauma, alterations that are, indeed, heritable and which increase one’s risk of mental illness, even in descendants who have not experienced poverty themselves.

As a result, healthcare providers must understand how generational poverty can impact patients’ mental health, long after the problem of poverty within the family has been solved.

In addition to the traumatic experience of poverty, intergenerational racism has been linked to higher rates of physical and mental health conditions among indigenous groups in Australia, including Aboriginal and Torres Strait Islander peoples. Once again, this can be connected not only to the deleterious effects of economic and healthcare inequities, but also to the generational impacts of chronic stress, fear, and anxiety in the face of racial trauma.

The Takeaway

Trauma can inflict pain that lasts not only for a lifetime but for generations. Indeed, traumatic experiences, especially those occurring in childhood, can produce heritable genetic alterations that may leave one’s descendants at elevated risk for mental illnesses, such as PTSD. However, as our understanding of the complex relationship between trauma, genetics, and mental illness grows, so do the hope and promise for more effective prevention and treatment regimes in the future.