A client came to me not long ago and told me of the immense trauma her own mother experienced as a five year old child. She was wondering how much, if at all, her mother’s trauma had impacted on her own life, which had been marked by significant anxiety.

The concept of trauma is well known these days, but less widely understood is the intergenerational transmission of trauma effects, where the emotional and psychological wounds of one generation can be passed down to another. Without knowing it, my client was talking about this intriguing phenomenon; trauma's ability to transcend generations.

The concept of intergenerational trauma was first introduced through descriptions of the behavioral and clinical problems experienced by the offspring of Holocaust survivors, beginning in the late 60’s and followed up by multiple studies in the years following. Similar symptoms were later described by the offspring of those who served in the Vietnam war. From these beginnings, there has been an increasing understanding of the universality of this phenomenon, and the profound impact of trauma on the psychological well-being and physiological responses of subsequent generations. 

Discussions have also evolved, over time, to consider the historical effects of traumatic events such as slavery, genocide and other forms of oppression, on groups of people, cultures, and subsequent generations. This is particularly pertinent to those of us living in New Zealand, where our early history of colonisation has contributed to multiple generations of our Māori people experiencing the effects of historical trauma.

So, what does the science say? 

Was it possible that my client’s mother’s trauma could have contributed to her lifetime of psychological distress and anxiety? And if so, what was the mechanism of transference? The answer to this question is complex, as there are multiple cultural, social, familial and neurobiological explanations, which may include, one or more of the following:

• Parents with a history of trauma may have high levels of anxiety or other mood difficulties, and exhibit poor coping strategies or emotional regulation skills. A powerful way children learn, is through observing and imitating their parent’s behaviour and responses, and as a result, they can often adopt similar cognitive and emotional patterns. In this case, children of trauma survivors may instinctively use strategies similar to their parents, when faced with stressful situations.

• Some children may strongly identify with their parent’s traumatic experiences, which can lead them to develop a deep psychological internalization of the trauma (the process of external ideas, values, attitudes, norms and behaviours, shaping our identity, and how we think, feel, and act), reinforcing its impact across generations. 

•  Research has revealed biological mechanisms that may be implicated in the transmission of trauma through the generations. For example, alterations in the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the body's stress response, have been observed in individuals exposed to trauma. These alterations can be passed down to subsequent generations, contributing to an increased vulnerability to stress-related disorders.

•  Studies using animal models have demonstrated that trauma can result in structural and functional changes in specific brain regions, including the amygdala, prefrontal cortex, and hippocampus, which are involved in emotional memory, fear conditioning, and stress regulation. Disruptions in their functioning can be passed down to subsequent generations, affecting their sensitivity to stress and their ability to regulate emotions effectively.

• Trauma may induce epigenetic changes that impact mitochondrial function. Epigenetic changes refers to modifications in how genes are expressed or "turned on" and "turned off" without altering the underlying DNA sequence. Mitochondria are the tiny structures found inside cells that act as little energy generators that help keep the cells running smoothly. Animal and human studies suggest these epigenetic modifications can be inherited by offspring, and influence their susceptibility to mental health disorders and stress responses.

The implications of emerging research in this field are far from conclusive, but they do suggest that the environmental wounds inflicted on one generation may be transmitted to the next. It appears that some offspring, at least, may experience an increase in sensitivity to stress, difficulty regulating their emotions effectively, and heightens their vulnerability to mental health disorders such as post-traumatic stress disorder (PTSD), depression, and anxiety disorders. Of course moderating factors can also influence the impact of intergenerational trauma on individuals and communities, such as personality characteristics, life experiences, social supports, or external stressors such as poverty or discrimination, to name a few.

So the answer to my client’s question is - most likely yes!

This was a powerful insight for her, as her increased self-awareness and understanding of her family’s history helped her make sense of her own experiences. She was able to see that her lifetime of anxiety was not due to some inherent deficit in her, a fear she had carried all her life, but was understandable in the context of her mother’s own history of trauma and the rippling effect through the generations. This realization provided a new lens through which she could view her life and experiences. It allowed her to reframe her narrative, fostering a sense of compassion for herself and her mother, and opened the door for her to heal and grow.