When we hear the word ‘trauma’ our perception is generally to assume this defines severe, life-altering events: a car accident, the loss of a loved one, a war veteran or abuse. But an individual’s experience with trauma can extend beyond the perceived norm. More accurately, trauma can be described as a sense of rupture; a fearful, dangerous or shocking event that interferes with the safety of the body and mind [1]. If we think of trauma from the perspective of safety, we can begin to view its potential impact from a wider lens. Events which disrupt the feeling of safety can look differently for everyone. For some this may look like a stressful birth, childhood bullying, feelings of neglect as a child, a miscarriage, extreme psychosocial stress, burnout, parent’s divorce, your divorce, relationship conflicts or financial worries. For others, their trauma may have begun before they were even born.
The theory of generational trauma has been long researched but more recently is gaining widespread attention due to its emerging clinical evidence. Trauma can physically alter regions of the brain dealing with memory, learning, emotions and social behaviors while also having the ability to alter a person’s epigenetics [2]. Epigenetics is the study of how your environment and behaviors can affect the function of your genes by turning them on or off [3]. Everyone has their own individual set of genes which writes the unique instructions for how their entire body functions. Some of these genes have the ability to be turned on and off by environmental factors such as nutrition, physical activity, environmental toxins, stressors and so forth. For example, there are genes found to be strongly correlated with obesity. You may carry this gene but it does not mean you will be obese. It does, however, mean you have a stronger predisposition to obesity but your environment will determine whether or not that obesity gene is turned on. This does not change your original DNA sequencing but rather changes how your genes are expressed. The change in expression of one’s genes can be inherited through multiple generations. This means if your grandmother experienced domestic abuse, based on her genetics, resiliency and her body’s unique response to this traumatic experience, the events that occurred hold the potential to alter her epigenetics which have the ability to be inherited by you [2,4].
Often the theory of inherited trauma can cause a person to perceive they are ‘doomed’ due to their family history, which is not the case seeing as how genes can similarly be turned ‘off’ just as they were turned ‘on.’ Also, trauma is a multifaceted yet individual experience making the outcomes variable and never guaranteed. For this reason, many researchers and psychologists are often hesitant to shed light on inherited trauma to avoid inaccurate assumptions.
Furthermore, as equally important as genetics are in the trauma response is the timing of the exposure to trauma. When trauma occurs during periods of rapid development such as in utero, the newborn phase, early childhood and adolescence, the impacts on mental health and hormones tend to be more prominent and longer-lasting [1].
Despite the hesitations, clinical evidence shows the epigenetic changes in the offspring of trauma survivors, and in those who experience trauma first-hand, have shown to impair the development and function of the HPA axis (hypothalamic-pituitary-adrenal) primarily by alterations in how the body is able to produce and utilize a hormone called, oxytocin [1,5].
oxytocin: the love hormone
Oxytocin is most commonly known as the ‘love hormone’ for its feel-good role in social behaviors, interactions, bonding, breast milk production and childbirth. It also helps regulate electrolytes (minerals), metabolism and cardiovascular homeostasis. Oxytocin is a neurohormone produced in a region of the brain called the hypothalamus (the H in HPA axis) and released by the pituitary gland (the P in HPA axis) [1]. Oxytocin receptors are located throughout the body in the reproductive tract, kidneys, heart, pancreas and fat cells [1]. This means wherever receptors are present, oxytocin can bind and alter the function or production of other hormones in that part of your body. And as mentioned, oxytocin receptors are virtually everywhere which means they also influence glucose metabolism via the pancreas, fat storage, mineral balances via the kidneys [1]. Exposure to trauma, whether inherited or self-experienced, alters the neurons in your brain which change how we produce oxytocin, how much oxytocin we can produce and how oxytocin binds to receptors throughout our body [1,5,6]. Without sufficient production of oxytocin, mood disorders are prevalent and dysregulation of the HPA axis occurs interfering with vital hormone production and communication.
the HPA axis (hypothalamic-pituitary-adrenal)
The HPA axis is a communication network of hormones and glands linking the hypothalamic region in the brain to the pituitary gland and further to the adrenal gland. This axis means these areas of the body are in constant communication and feedback. The pituitary gland is responsible for secretion of ovulatory hormones (LH and FSH), thyroid hormones and a hormone called Adrenocorticotropic Hormone (ACTH) which stimulates the adrenal gland to release stress hormones when appropriate [7]. The presence of oxytocin determines the timing, amount and duration of ACTH release [1]. The hormones secreted by the adrenal gland in response are called glucocorticoids (cortisol and DHEA) which regulate the stress response as well immune function, central nervous system and metabolic health. When trauma is experienced or inherited, the way the brain is able to produce oxytocin is altered which dysregulates this messaging system leading to decreased ACTH release and therefore a blunted cortisol response [1,5].
More commonly, people see high cortisol levels on lab testing and are concerned about the significant stress the body is encountering (or the increased demand which the body does not have the resources for). This is an accurate concern as high cortisol levels represent earlier stages of stress indicating your body is still working hard to fight to return to homeostasis [5]. While these high cortisol levels are not ideal, in actuality a low cortisol response to stress is the more concerning factor. Low cortisol is often indicative of the burnout, end stages of stress where your body has fought all it could fight and is no longer able to compensate whether due to a sudden, intense event or recurrent exposure to events that threaten the safety of your body [5].
Blunted cortisol responses have been shown in children whose mothers were exposed to childhood trauma, neonates lacking bonding in the postnatal period, the offspring of Holocaust survivors, combat veterans with PTSD, infants in women of child abuse and infants in utero during the Dutch Famine further emphasizing the evidence of inherited trauma [2,4].
Any abnormal production of hormones involved in the HPA axis, whether high or low, causes interference with homeostasis and maintenance of hormone production in the axis leading to system wide impacts.
References
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