The Effect of Trauma on the Brain: Impacts on Structure, Function and Performance

Dr. Donna L. Roberts

Trauma results in a fundamental reorganization of the way mind and brain manage perceptions. It changes not only how we think and what we think about, but also our very capacity to think. — Bessel van der Kolk, M.D.

Trauma refers to a distressing or life-threatening event that overwhelms an individual’s ability to cope with and process the experience. Trauma, whether experienced as a single event or as a chronic stressor, can have significant impacts on the brain, leading to a range of physical and psychological symptoms. Research has shown that trauma can alter the structure, chemistry and function of the brain, affecting emotional regulation, memory, attention, and decision-making processes (Van der Kolk, 2014). Understanding these changes is crucial in developing effective interventions for individuals who have experienced trauma.

Changes in Brain Structure, Function, and Chemistry

One of the primary effects of trauma on the brain includes changes in the actual structure of specific areas. Studies have found that individuals who have experienced trauma have smaller hippocampal volumes (Bremner, 2006; Smith, 2005). The hippocampus is involved in memory consolidation and retrieval, as well as in regulating the stress response (Cahill & Alkire, 2003; McEwen, 2012). Trauma can lead to structural changes in the hippocampus that result in impaired functioning, including difficulties with memory processing and retrieval and the ability to process and cope with stress (Bremner, 2006; McEwen, 2012). Individuals with a history of trauma may experience fragmented memories, dissociation, and flashbacks, which can be triggered by reminders of the traumatic event.

Additionally, trauma can lead to changes in the prefrontal cortex, a region of the brain that is responsible for executive functioning, decision-making, and impulse control (Arnsten, 2009; Teicher & Samson, 2016). Trauma can lead to reduced prefrontal cortex activity and connectivity, which can contribute to difficulties with attention, planning, and decision-making, as well as difficulties with regulating emotions and behaviors (Van der Kolk, 2014).

I became what I am today at the age of twelve, on a frigid, overcast day in the winter of 1975 . . . That was a long time ago, but it’s wrong what they say about the past . . . Looking back now I realize I have been peeking into that deserted alley for the last twenty-six years. — Khaled Hosseini, The Kite Runner

Trauma can also impact brain function by altering the activity of neurotransmitters, chemicals in the brain that facilitate communication between neurons. Research has shown that individuals who have experienced trauma may have altered levels of neurotransmitters such as serotonin, dopamine, and norepinephrine (McCrory et al., 2011). These changes can lead to symptoms such as depression, anxiety, and difficulty sleeping.

One of the most common ways in which trauma affects the brain is through dysregulation of the stress response system. Traumatic experiences can lead to chronic activation of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased cortisol levels and prolonged activation of the sympathetic nervous system (SNS) (McEwen, 2012; Pitman et al., 2012). This persistent state of hyperarousal can lead to changes in the brain’s limbic system, including the amygdala and hippocampus, which are involved in processing emotions and memories (Bremner, 2006).

The amygdala plays a crucial role in the processing and regulation of emotional responses, particularly fear and anxiety (Davis & Whalen 2001). Trauma can lead to increased amygdala activity and hyperreactivity to stimuli that are perceived as threatening or dangerous, even when the actual danger has passed (Van der Kolk, 2014). This heightened amygdala response can result in increased anxiety, hypervigilance, and emotional dysregulation.

Impacts on Cognitive and Emotional Processing

In addition to the impact on brain structure, function, and chemistry, trauma can also have significant consequences for cognitive and emotional processing. Individuals who have experienced trauma may have difficulty with attention, concentration, and memory (van der Kolk, 2014). These reactions may be closely related to the aforementioned changes in brain structure, as well as the impact of trauma on the stress response system.

Trauma is also considered a potential causal factor in emotional dysregulation, including symptoms such as anxiety, depression, and anger (Cloitre et al., 2013). These emotional symptoms are theorized as being related to changes in brain chemistry, such as alterations in the levels of neurotransmitters like serotonin and norepinephrine, as well as changes in brain function related to the prefrontal cortex and amygdala. These symptoms can further impact developmental processes, social interaction and interpersonal functioning, including difficulties with trust, intimacy, and relationships (Herman, 1992).

Being traumatized means continuing to organize your life as if the trauma were still going on — unchanged and immutable — as every new encounter or event is contaminated by the past. — Bessel van der Kolk, M.D.

Treating Trauma-Related Brain Changes

It is important to note that the impacts of trauma on the brain are complex and multifaceted, and can vary depending on a range of factors, including the type and severity of the trauma, the developmental stage of the individual, and their social support and coping resources. However, understanding the impacts of trauma on the brain is essential for developing effective interventions for individuals who have experienced trauma.

One approach that has shown promise in treating trauma-related brain and behavioral changes is trauma-focused cognitive behavioral therapy (TF-CBT). This approach integrates cognitive and behavioral techniques to help individuals process traumatic experiences and develop coping skills (Cohen et al., 2017). TF-CBT has been found to be effective in reducing symptoms of trauma-related stress disorders and improving brain function and structure in areas such as the prefrontal cortex and hippocampus (Van der Kolk, 2014).

These studies highlight the importance of addressing the impact of trauma on the brain and the need for effective interventions that can help individuals with trauma-related symptoms. Additional evidence-based treatments include eye movement desensitization and reprocessing (EMDR) and medication (Pitman et al., 2012). The use of mindfulness-based interventions and other mind-body practices such as yoga and meditation have also shown promise in reducing the effects of trauma on the brain and improving psychological well-being (Van der Kolk, 2014).

Trauma can have profound and far-reaching impact on the brain, including changes in brain structure, function, and chemistry. These changes can lead to a range of physical and psychological symptoms and difficulties, and thus it is crucial to understand and address these impacts in order to effectively treat and support individuals who have experienced trauma. Further research is needed to fully understand the complex mechanisms underlying the effects of trauma on the brain and to identify optimal interventions to address trauma-related symptoms.


Arnsten, A. F. T. (2009). Stress signalling pathways that impair prefrontal cortex structure and function. Nature Reviews Neuroscience, 10(6), 410–422.

Bremner J. D. (2006a). Stress and brain atrophy. CNS & neurological disorders drug targets, 5(5), 503–512.

Bremner, J. D. (2006b). Traumatic stress: effects on the brain. Dialogues in Clinical Neuroscience, 8(4), 445–461.

Cahill, L., & Alkire, M. T. (2003). Epinephrine enhancement of human memory consolidation: Interaction with arousal at encoding. Neurobiology of Learning and Memory, 79(2), 194–198.

Cloitre, M., Courtois, C. A., Charuvastra, A., Carapezza, R., Stolbach, B. C., & Green, B. L. (2011). Treatment of complex PTSD: Results of the ISTSS expert clinician survey on best practices. Journal of Traumatic Stress, 24(6), 615–627. doi: 10.1002/jts.20697.

Cohen, J. A., Mannarino, A. P., & Deblinger, E. (2017). Trauma-focused cognitive behavioral therapy for children and adolescents (2nd ed.). Guilford Press.

Davis, M., & Whalen, P. J. (2001). The amygdala: vigilance and emotion. Molecular psychiatry, 6(1), 13–34.

Herman, J. L. (1992). Trauma and recovery: The Aftermath of Violence — from Domestic Abuse to Political Terror.Basic Books.

McCrory, E. J., De Brito, S. A., & Viding, E. (2010). Research review: the neurobiology and genetics of maltreatment and adversity. Journal of Child Psychology and Psychiatry, 51(10), 1079–1095. doi: 10.1111/j.1469–7610.2010.02271.x.

McEwen, B. S. (2012). Brain on stress: How the social environment gets under the skin. Proceedings of the National Academy of Sciences, 109 (Supplement 2), 17180–17185.

Pitman, R. K., Rasmusson, A. M., Koenen, K. C., Shin, L. M., Orr, S. P., Gilbertson, M. W., & Milad, M. R. (2012). Biological studies of post-traumatic stress disorder. Nature Reviews Neuroscience, 13(11), 769–787.

Smith, M. E. (2005). Bilateral hippocampal volume reduction in adults with post‐traumatic stress disorder: A meta‐analysis of structural MRI studies. Hippocampus, 15(6), 798–807. . doi: 10.1002/hipo.20102.

Teicher, M. H., & Samson, J. A. (2016). Annual research review: Enduring neurobiological effects of childhood abuse and neglect. Journal of Child Psychology and Psychiatry, 57(3), 241–266. doi: 10.1111/jcpp.12507.

Van der Kolk, B. A. (2014). The body keeps the score: Brain, mind, and body in the healing of trauma.Penguin.

Comments / 2

Published by

Writer and university professor researching media psych, generational studies, addiction psychology, human and animal rights, and the intersection of art and psychology.

Canandaigua, NY

More from Dr. Donna L. Roberts

Comments / 0