How Trauma Affects the Brain

How Trauma Affects the Brain

This month is Mental Health Awareness month and it's amazing to see how much awareness and conversation around trauma has grown in recent years. I love that people are finally coming together to acknowledge that everyone has experienced something difficult in their lives, and that it's okay to talk about it and the way it has impacted us. It's a sweet reminder that we're all human and have the capacity to support and uplift one another, no matter what we've been through. 

One problem that I see in the discussions around trauma is that often we talk about trauma without actually understanding how it can impact us on a cellular level - or really what it does to our body or brain. Understanding the impact of trauma on our brain helps us understand how, and why, it has the power to shape our life. So, let's get into it. 

I always think it's important to start with understanding how our nervous system, including our brain, reacts to and deals with trauma. During times of crisis, chaos, and traumatic experiences, we enter "survival mode”. This survival mode has a huge downstream effect not only on our brain but also our whole nervous system, our HPA axis and endocrine system (read: our hormones) and much more.

When a person experiences trauma, their brain also undergoes changes in structure and function, which can affect the way they think, feel, and behave. The way the brain responds to stress and traumatic stress involves several key areas of the brain like the amygdala, hippocampus, and prefrontal cortex. Chemicals like cortisol and norepinephrine are also involved and traumatic stress can have lasting effects on these regions of the brain, leading to changes in their structure and function. 

Emotional Regulation and Processing (The Amygdala and Prefrontal Cortex)

One of the brain areas most affected by trauma is the amygdala, which is responsible for processing emotions such as fear, anger, and sadness. During traumatic experiences, the amygdala becomes overactive, causing a person to feel intense emotions that are difficult to control. This can lead to symptoms such as anxiety, panic attacks, and flashbacks. Alongside the amygdala, which can become too active, another brain area affected by trauma is the prefrontal cortex, which is responsible for decision-making, problem-solving, and self-regulation. Trauma can cause the prefrontal cortex to become less active, making it difficult for a person to think clearly, regulate their emotions, and make good decisions.

Between an increase in amygdala activity, and a reduction in prefrontal cortex activity, regulating our emotions, thinking clearly, and making good decisions may become increasingly challenging. This, as well as the nervous system dysregulation, contributes to why we are increasingly likely to experience symptoms like anxiety and depression, feeling more erratic and more emotional, to be more hypersensitive and even have difficulty sleeping.

Impact on Memory (Hippocampus)

Trauma can also affect the hippocampus, which is responsible for memory formation and storage. During traumatic experiences, the hippocampus can be damaged, leading to memory problems and difficulty recalling details of the traumatic event. The impact of traumatic stress on our memory is particularly clear when we look at research around PTSD and the way that chronic stress affects the hippocampus (the area most involved in memory storing). The impact on memory can work both ways. An incredible piece of research showed that in a study, women who have experienced abuse and have PTSD had difficulty activating their hippocampus during a memory task compared to those who did not experience abuse. Moreover, the women who experienced abuse and PTSD had smaller hippocampal volume measured through MRI compared to those who experienced abuse without PTSD and those who did not experience abuse and PTSD. Equally, in terms of memory storage in relation to PTSD, it is thought that deficits in the medial prefrontal cortex, which inhibit the amygdala, may enhance the effects of the amygdala. This may be connected to the increased frequency and intensity of traumatic memories which could go some way to explaining why trauma processing in those with PTSD is such an overwhelming and life-changing process.

Increased Stress Response / Sensitivity (Elevated Glucocorticoid Response)

The neurochemical systems in the brain that play a critical role in the stress response, such as cortisol and norepinephrine, are also affected by trauma.  Experiencing trauma and chronic stress can make our bodies more sensitive to stress. This means that when we experience stress, our body produces more of a group of hormones called glucocorticoids than it normally would in order to help regulate our body's stress response. The increase in these chemicals can lead to symptoms such as hypervigilance, irritability, and sleep disturbances.

Research supports this hypothesis. Studies on animals have found that maternal deprivation for babies leads to reduced glucocorticoid receptors in specific parts of the brain. This means that experiencing traumatic stress (through lack of mothering, as an example) can increase the body's response to stress, leading to heightened cortisol and norepinephrine levels when exposed to subsequent stressors later in life. 

New Neuron Growth

Trauma and traumatic stress can also impact our future brain growth and development. Neurogenesis is the process of generating new neurons in the brain. It occurs primarily in the hippocampus, a region of the brain that plays a critical role in learning, memory, and emotional regulation. However, animal studies are showing that the production of new brain cells in adult primates decreased significantly when they were exposed to a stressful experience. This indicates that stress can impact the creation of new cells in the brain of primates. Studies have shown that stress is linked to decreased brain-derived neurotrophic factor (BDNF), and/or increased glutamate levels, which can inhibit neurogenesis.

HPA Axis 

It’s not just the brain that is impacted by traumatic and chronic stress, however. Research conducted on animals has demonstrated that stress experienced early in life can lead to long-lasting effects on the HPA axis; this is our hypothalamic-pituitary-adrenal (HPA) axis and it’s something we are going to hear a lot more about in the coming years. The HPA axis controls our body’s stress response and impacts all of our hormones. So, trauma can impact our entire endocrine system also. 


In summary, trauma can significantly impact the way our brain functions, specifically affecting the amygdala, hippocampus and prefrontal cortex too.  So if you’ve experienced some sort of trauma and then found yourself experiencing emotional dysregulation, difficulty focusing, and memory problems as well as just not feeling happy, bright, sparky or optimistic, know that this is normal and is a result of brain changes brought on by the trauma. It sounds scary, but if you are experiencing any of these symptoms, please know that it's okay to seek help and that healing is possible. 

Rewiring your brain and balancing your neurotransmitters, stress response, nervous system, and other physiological responses IS possible and it’s amazing to see the world waking up to how we can all step into this space together. A combination of therapeutic modalities, including talk therapy, EMDR therapy, emotional release therapy, somatic therapy, and nervous system regulation is a great place to start to create new neural pathways and change old patterns of thought and behavior. Lifestyle changes such as a nutrient-rich diet, gentle exercise, mindfulness practices, supplements (Lion’s Mane is a great option) and healthy eating habits can support the healing process by reducing stress and promoting the production of feel-good neurotransmitters such as serotonin and dopamine. 

By addressing the physical, emotional, and psychological aspects of trauma, it is possible to heal and move forward in a positive and healthy way. I’m here on this journey with you.