The Science of Wellbeing

Calendar-alt Facebook Instagram Youtube
Menu

The Link Between Complex Trauma and the Immune System

trauma-effects-on-our-immune-system (1)

Complex trauma, often characterised by prolonged exposure to interpersonal trauma, has far-reaching impacts on both mental and physical health. While it is widely known that trauma affects emotional regulation and cognition, of late, much attention has been paid to its effects on the immune system. Emerging research highlights that trauma, including complex trauma (CPTSD), can disrupt immune function1 2, leading to vulnerabilities in combating everyday infections like colds, flu, COVID, and sickness bugs as well as weakened responses to both viral and bacterial vaccinations. In this post, I explore some of the biological and psychological mechanisms underlying this connection, followed by a discussion on how this disruption can contribute to more chronic health issues.

Biological and Neurobiological Mechanisms

Neurobiologically, trauma also affects brain areas like the amygdala, prefrontal cortex, and hippocampus, which regulate stress and immune responses3 4. Heightened amygdala activity in trauma survivors keeps the body in a state of hypervigilance, which inhibits the immune system’s ability to respond effectively to pathogens. This constant state of arousal leaves trauma survivors more prone to frequent and severe bouts of illness.

The Traditional View: Cortisol Overproduction and Immune Suppression

The prevailing theory in trauma research has long suggested that chronic activation of the body’s stress response system, specifically the hypothalamic-pituitary-adrenal (HPA) axis, leads to the overproduction of cortisol in trauma survivors, including those with PTSD and CPTSD. The sustained elevation of cortisol, a hormone crucial for managing stress, is believed to suppress the immune system in order to prioritise the body’s resources for immediate survival.

This prolonged cortisol release, coupled with dysregulated production of oxytocin (another hormone involved in the stress response), impairs the immune system’s ability to defend against infections like colds, flu, and other viruses. Studies have shown that chronic stress can reprogramme immunoprotective cells5, suppress protective immune responses (wound healing, vaccination, anti-infectious agent, anti-tumor) and/or exacerbate pathological immune responses (pro-inflammatory, autoimmune)6, making trauma survivors more susceptible to everyday infections. Additionally, oxytocin, under certain conditions, can increase sensitivity to environmental stressors, which may further heighten the body’s stress response and worsen immune regulation7.

The combined dysregulation of these hormones not only heightens stress responses but also contributes to overall immune imbalance, increasing vulnerability to illness and slowing down recovery from infections8.

New Findings: A Shift from Cortisol Overproduction to Imbalance

While the traditional view of cortisol overproduction remains widely accepted, newer research has shifted the focus towards a more nuanced understanding of cortisol regulation in trauma survivors. This emerging perspective suggests that the problem is not simply too much cortisol but rather an imbalance in how the body responds to it.9 10

In trauma survivors, some studies11 12 show that the body develops increased sensitivity to cortisol due to heightened activity of the glucocorticoid receptors (GRs). These receptors are more responsive to cortisol, meaning that even small amounts can trigger the body’s usual stress and immune responses. Paradoxically, despite this increased sensitivity, trauma survivors often exhibit lower overall production of cortisol. This is because the body’s stress system, in an attempt to balance things out, releases less cortisol to avoid overstimulation of these sensitive receptors.

However, this imbalance creates a situation where the cortisol levels are too low to effectively regulate inflammation. Normally, cortisol acts as a brake on inflammation, helping the body to recover from illness. But in trauma survivors, the increased GR sensitivity means cortisol’s anti-inflammatory effects are weaker, and the body cannot fully control the inflammatory response. This persistent low-level inflammation overburdens the immune system, making it harder to fight off common infections like colds or flu and prolonging recovery times.

The Consequences: Immune Dysregulation and Chronic Stress

This dysregulation of cortisol and inflammation results in a weakened and dysregulated immune system. In trauma survivors, the immune system is not fully suppressed but struggles to function properly. Chronic stress, combined with unchecked inflammation, leaves trauma sufferers more vulnerable to infections. The body’s immune response becomes inefficient and sluggish, leading to longer recovery times from illnesses and a higher likelihood of falling ill more frequently.

Moreover, this immune dysregulation is part of a broader disruption of the autonomic nervous system (ANS). In trauma survivors, the sympathetic nervous system (responsible for the “fight-or-flight” response) often remains chronically activated. This constant state of activation further impairs immune function by prioritising immediate survival over maintenance processes, such as immune defence. As a result, trauma survivors often live in a state of hypervigilance, which leaves their immune system less capable of responding effectively to pathogens, making them more prone to frequent illnesses.

The Broader Impact: Chronic Inflammation and Trauma Symptoms

As a consequence of immune dysregulation, trauma survivors experience increased or imbalanced levels of pro-inflammatory cytokines. These proteins signal molecules that promote inflammation in response to infection or injury.

*Inflammation increases blood flow to the affected area, bringing immune cells, oxygen, and nutrients that help destroy invading microbes, such as bacteria or viruses.

In a healthy immune system, the production of cytokines are tightly regulated. However, when the immune system becomes dysregulated and cortisol secretion becomes disrupted there is an overproduction or imbalance of these cytokines, contributing to a persistent inflammatory state13 14.

Inflammation is closely linked to conditions such as PTSD, long COVID, and fibromyalgia, which share overlapping symptoms, including fatigue, headaches, and muscle pain. These conditions are all connected to immune system dysfunction caused by chronic inflammation and stress, further impairing the body’s ability to fight infections and heal efficiently.

So, while the traditional view emphasises cortisol overproduction as the primary mechanism suppressing the immune system in trauma survivors, newer research highlights an imbalance in cortisol regulation and GR sensitivity. This imbalance leads to increased inflammation and a dysregulated immune system, leaving trauma survivors more prone to illness and slower to recover. Understanding these mechanisms better helps explain why trauma sufferers often face long-term health challenges, including frequent infections and chronic immune dysfunction.

Chronic Stress: A Hidden Barrier to Vaccine Effectiveness

Emerging research increasingly highlights the impact of chronic stress on immune function, particularly its effects on vaccine efficacy. Prolonged stress alters both antibody production and T-cell responses15 16 17, which are crucial in defending the body against viral infections. This dysregulation reduces the effectiveness of vaccines, impairing the body’s ability to produce strong, lasting immunity. These findings underline the need to address stress in healthcare to optimise vaccine responses and overall immunity.

The Impact on the Gastrointestinal Tract

Moreover, the gut microbiome plays a crucial role in the immune system’s health18. Stress, emotions, and trauma can alter the bacterial composition in the digestive tract. Hormones like cortisol and epinephrine disrupt gut bacteria19, damaging the mucosa and allowing toxins to leak into the bloodstream, triggering inflammation. This inflammation has been linked to psychiatric disorders20 and further exacerbates immune system dysfunction. Research shows that gut bacteria impact brain function, cognition, and emotional regulation, meaning that trauma-induced disruptions in the gut microbiome can worsen both mental and physical health outcomes.8 22 23

Psychological Mechanisms

From a psychological perspective, the effects of trauma are also tied to emotional regulation, cognitive function, and behavioural patterns, all of which influence immunity. Trauma survivors often experience heightened anxiety, depression, and stress – factors that have been shown above to negatively affect immune function. The psychological burden of constantly being in a “threat detection” mode may prevent individuals from recovering fully from everyday illnesses, thus prolonging the duration of viral infections and bacterial illnesses.

Furthermore, trauma survivors may engage in health-harming behaviours such as poor sleep hygiene, unhealthy eating patterns, substance abuse, and sedentary lifestyles, all of which contribute to weakened immunity. When the body is not well-nourished, adequately rested, or given time to recover, its ability to fend off everyday sicknesses like colds, flu, and other viral infections diminishes significantly.

Complex Trauma and Everyday Infections

Individuals with complex trauma often report being “run down” or getting sick more frequently than others. They may struggle to recover from common colds, flu, or infections like COVID-19, showing a lower tolerance for these illnesses. As mentioned, this immune vulnerability is a consequence of both physiological and psychological mechanisms, including chronic stress-induced immune suppression, HPA axis dysfunction, and a state of constant hypervigilance that taxes bodily resources.

Links to Chronic Health Issues

While much of this blog has focused on how complex trauma can weaken defenses against less chronic immune challenges, such as colds and flu, it is important to note that these immune disruptions may also be linked to more chronic health problems24. The chronic activation of the stress response system over time can contribute to conditions such as autoimmune disorders, chronic fatigue syndrome, and inflammatory diseases like rheumatoid arthritis or fibromyalgia.

Research shows that individuals with a history of trauma are at higher risk for chronic inflammation, which is a precursor to many long-term health issues. For instance, one study25 shows that individuals with PTSD exhibit a skewed immune response toward a pro-inflammatory state, with elevated levels of cytokines26, as well as increased immune-stimulatory and inflammatory cells.

Chronic trauma exposure can also lead to metabolic dysregulation, increasing the risk of metabolic disease (such as Type 2 Diabetes)27, cardiovascular disease27 29, pulmonary disease 29, and even certain cancers. Thus, while the immediate concern may be susceptibility to colds and infections, the long-term impact of complex trauma on immunity can be profound, leading to a variety of chronic, life-altering health conditions.

The Importance of Considering Trauma in Immune Dysregulation

Although there are many reasons why someone might have a poor immune system – including genetics, lifestyle factors, and environmental influences – it is crucial not to overlook the biological impacts of trauma. The immune system does not exist in isolation; it is intricately connected to both the nervous system and the brain, meaning that trauma-induced changes in stress regulation can have profound effects on immunity. Given this understanding, a person’s history of trauma should be carefully considered when addressing immune dysregulation, especially in individuals who show signs of lowered tolerance to everyday infections. By accounting for the role of trauma, we can offer more effective, compassionate, and holistic approaches to health care that recognise the full spectrum of factors contributing to immune dysfunction.

This is a fascinating and important topic, and I plan to share more research and insights in future posts. If you believe you are experiencing trauma symptoms from past events and may need support, I recommend seeking out a psychodynamic therapist who specialises in complex trauma and EMDR. You might also benefit from working with a somatic therapist who can address your physiological symptoms.

As I’ve mentioned EMDR above and having had EMDR therapy myself with amazing effects (a definite choice for reprocessing trauma memories), I have to share this EMDR session with you because it provides an excellent example of how Bilateral Stimulation (BLS), used in EMDR, helps the brain process traumatic memories with less emotional intensity and more cognitive control. BLS allows the brain to reassess and reframe the memory in a new way.

The idea is that by engaging the brain in a task – like the back-and-forth movement of BLS – the emotional intensity of the memory decreases. Brain scans show that BLS also calms the amygdala, reducing fear and anxiety responses, and helps the brain reprocess the trauma with less emotional charge. With repeated BLS, the brain reconsolidates the memory in a less distressing form, changing how it is stored. As a result, the memory can be recalled without the overwhelming emotional and physiological reactions that were once attached to it.

EMDR Therapy Demonstration: Dissociative Considerations

Additionally, if you’re interested in exploring the connection between emotions, the nervous system, and the immune system, I encourage you to look into Psychoneuroimmunology (PNI). It’s a captivating field, and I’m excited to dive deeper into it!

Remember, you’re not alone 💙

It’s important to note that much of the research in this area has focused on PTSD. Since Complex PTSD (CPTSD) is a more recent diagnosis, there is currently less research available. For now, we can assume that the physiological effects of CPTSD are similar to those of PTSD, as both conditions lead to heightened stress and often come with related issues such as anxiety and depression.

References

  1. Boscarino, J.A., 2009. Posttraumatic stress disorder and physical illness: Results from clinical and epidemiologic studies. Annals of the New York Academy of Sciences, 1071(1), pp.141-153. ↩︎
  2. Park, J. E., Ahn, H.-N. and Kim, W.-H. (2016) “Somatic Symptoms after Psychological Trauma,” Korean Journal of Psychosomatic Medicine. 한국정신신체의학회, 24(1), pp. 43–53. doi: 10.22722/KJPM.2016.24.1.043. ↩︎
  3. Saeed, F., Nussrat, S., Zafar, M., Khan, M., Jabeen, Q. and Bano, I., 2021. The Impact of COVID-19 on the Cardiovascular System. International Journal of Endocrinology, [online] Available at: https://onlinelibrary.wiley.com/doi/full/10.1155/2021/5599265 [Accessed 7 October 2024]. ↩︎
  4. Bruce S. McEwen, Central effects of stress hormones in health and disease: Understanding the protective and damaging effects of stress and stress mediators, European Journal of Pharmacology,
    Volume 583, Issues 2–3, 2008, Pages 174-185, ISSN 0014-2999, https://doi.org/10.1016/j.ejphar.2007.11.071 (https://www.sciencedirect.com/science/article/pii/S0014299908000277) ↩︎
  5. Barrett, T.J., et al., 2021. Chronic stress primes innate immune responses in mice and humans. *Cell Reports*, 36(10), p.109595. https://doi.org/10.1016/j.celrep.2021.109595. ↩︎
  6. Dhabhar, F.S. Effects of stress on immune function: the good, the bad, and the beautiful. Immunol Res 58, 193–210 (2014). https://doi.org/10.1007/s12026-014-8517-0 ↩︎
  7. Olff, M, et al., The role of oxytocin in social bonding, stress regulation and mental health: An update on the moderating effects of context and interindividual differences, Psychoneuroendocrinology, Volume 38, Issue 9, 2013, Pages 1883-1894, ISSN 0306-4530,
    https://doi.org/10.1016/j.psyneuen.2013.06.019. (https://www.sciencedirect.com/science/article/pii/S0306453013002369) ↩︎
  8. Oroian, B.A., Rogozea, L., Pătru, A., Tătaru, C., Băcilă, C., & Szabo, C., 2021. New metabolic, digestive, and oxidative stress-related manifestations associated with posttraumatic stress disorder. Antioxidants, 10(8), p.1168. (https://onlinelibrary.wiley.com/doi/full/10.1155/2021/5599265). ↩︎
  9. Somvanshi, P.R., 2021. Role of enhanced glucocorticoid receptor sensitivity in inflammation in PTSD: insights from computational model for circadian-neuroendocrine-immune interactions. American Physiological Society, 319(1), p. E41-E66. (https://journals.physiology.org/doi/full/10.1152/ajpendo.00398.2019) ↩︎
  10. Evan D Kanter, Charles W Wilkinson, Allen D Radant, Eric C Petrie, Dorcas J Dobie, Miles E McFall, Elaine R Peskind, Murray A Raskind,
    Glucocorticoid feedback sensitivity and adrenocortical responsiveness in posttraumatic stress disorder, Biological Psychiatry, Volume 50, Issue 4, 2001, Pages 238-245, ISSN 0006-3223, https://doi.org/10.1016/S0006-3223(01)01158-1.
    (https://www.sciencedirect.com/science/article/pii/S0006322301011581) ↩︎
  11. https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1002379 ↩︎
  12. https://www.psych.theclinics.com/article/S0193-953X(02)00002-3/abstract ↩︎
  13. Gola, H., Engler, H., Sommershof, A. et al. Posttraumatic stress disorder is associated with an enhanced spontaneous production of pro-inflammatory cytokines by peripheral blood mononuclear cells. BMC Psychiatry 13, 40 (2013). https://doi.org/10.1186/1471-244X-13-40 ↩︎
  14. Renner, V., Schellong, J., Bornstein, S. et al. Stress-induced pro- and anti-inflammatory cytokine concentrations in female PTSD and depressive patients. Transl Psychiatry 12, 158 (2022). https://doi.org/10.1038/s41398-022-01921-1 ↩︎
  15. Dafne M. Silberman, Miriam R. Wald, Ana Marı́a Genaro,
    Acute and chronic stress exert opposing effects on antibody responses associated with changes in stress hormone regulation of T-lymphocyte reactivity, Journal of Neuroimmunology, Volume 144, Issues 1–2,
    2003, Pages 53-60, ISSN 0165-5728,
    https://doi.org/10.1016/j.jneuroim.2003.08.031.
    (https://www.sciencedirect.com/science/article/pii/S0165572803003308) ↩︎
  16. https://www.discoverymedicine.com/Ronald-Glaser/2009/07/18/stress-damages-immune-system-and-health/ ↩︎
  17. Annette Sommershof, Hannah Aichinger, Harald Engler, Hannah Adenauer, Claudia Catani, Eva-Maria Boneberg, Thomas Elbert, Marcus Groettrup, Iris-Tatjana Kolassa,
    Substantial reduction of naïve and regulatory T cells following traumatic stress,
    Brain, Behavior, and Immunity, Volume 23, Issue 8, 2009, Pages 1117-1124, ISSN 0889-1591, https://doi.org/10.1016/j.bbi.2009.07.003.
    (https://www.sciencedirect.com/science/article/pii/S0889159109003808) ↩︎
  18. Shi, N., Li, N., Duan, X. et al. Interaction between the gut microbiome and mucosal immune system. Military Med Res 4, 14 (2017). https://doi.org/10.1186/s40779-017-0122-9 ↩︎
  19. Liisa Hantsoo, Babette S. Zemel,
    Stress gets into the belly: Early life stress and the gut microbiome,
    Behavioural Brain Research,
    Volume 414,
    2021,
    113474,
    ISSN 0166-4328,
    https://doi.org/10.1016/j.bbr.2021.113474.
    (https://www.sciencedirect.com/science/article/pii/S0166432821003624) ↩︎
  20. Glynn, H., Möller, S.P., Wilding, H. et al. Prevalence and Impact of Post-traumatic Stress Disorder in Gastrointestinal Conditions: A Systematic Review. Dig Dis Sci 66, 4109–4119 (2021). https://doi.org/10.1007/s10620-020-06798-y ↩︎
  21. Oroian, B.A., Rogozea, L., Pătru, A., Tătaru, C., Băcilă, C., & Szabo, C., 2021. New metabolic, digestive, and oxidative stress-related manifestations associated with posttraumatic stress disorder. Antioxidants, 10(8), p.1168. (https://onlinelibrary.wiley.com/doi/full/10.1155/2021/5599265). ↩︎
  22. M Hasan Mohajeri, Giorgio La Fata, Robert E Steinert, Peter Weber, Relationship between the gut microbiome and brain function, Nutrition Reviews, Volume 76, Issue 7, July 2018, Pages 481–496, https://doi.org/10.1093/nutrit/nuy009 ↩︎
  23. Rogers, G., Keating, D., Young, R. et al. From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Mol Psychiatry 21, 738–748 (2016). https://doi.org/10.1038/mp.2016.50 ↩︎
  24. Spitzer, Carsten MD; Barnow, Sven PhD; Völzke, Henry MD; John, Ulrich PhD; Freyberger, Harald J. MD; Grabe, Hans Joergen MD. Trauma, Posttraumatic Stress Disorder, and Physical Illness: Findings from the General Population. Psychosomatic Medicine 71(9):p 1012-1017, November 2009. | DOI: 10.1097/PSY.0b013e3181bc76b5 ↩︎
  25. Wang, Z., Caughron, B. and Young, R.I., 2017. Posttraumatic stress disorder: An immunological disorder? Frontiers in Psychiatry, 8. Available at: https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2017.00222 [Accessed 7 October 2024]. DOI: 10.3389/fpsyt.2017.00222. ↩︎
  26. Cytokines are small proteins that act as chemical messengers in the immune system, regulating the growth and activity of immune and blood cells. Elevated levels of cytokines can cause a range of symptoms, from mild to life-threatening. These symptoms can include: Fever, Chills, Tiredness, Nausea and vomiting, Diarrhea, Headaches, Cough, Low blood pressure, Joint pain, and Muscle pain ↩︎
  27. Kristina Reed, Shiloh Cleveland, Jordan Thomas, Aileen Hsu, Annie Jeong, Jessica Nguyen, Aarti Patel, Sheila Zhang, Jennifer A. Sumner, Chapter 10 – PTSD and physiology: The long-term effects of PTSD and relation to epigenetics, physical health, and chronic diseases, Editor(s): Nagy A. Youssef, In Translational Epigenetics, Epigenetics of Stress and Stress Disorders, Academic Press, Volume 31,
    2022, Pages 137-162, ISBN 9780128230398, https://doi.org/10.1016/B978-0-12-823039-8.00016-2.
    (https://www.sciencedirect.com/science/article/pii/B9780128230398000162) ↩︎
  28. Kristina Reed, Shiloh Cleveland, Jordan Thomas, Aileen Hsu, Annie Jeong, Jessica Nguyen, Aarti Patel, Sheila Zhang, Jennifer A. Sumner, Chapter 10 – PTSD and physiology: The long-term effects of PTSD and relation to epigenetics, physical health, and chronic diseases, Editor(s): Nagy A. Youssef, In Translational Epigenetics, Epigenetics of Stress and Stress Disorders, Academic Press, Volume 31,
    2022, Pages 137-162, ISBN 9780128230398, https://doi.org/10.1016/B978-0-12-823039-8.00016-2.
    (https://www.sciencedirect.com/science/article/pii/B9780128230398000162) ↩︎
  29. Spitzer, Carsten MD; Barnow, Sven PhD; Völzke, Henry MD; John, Ulrich PhD; Freyberger, Harald J. MD; Grabe, Hans Joergen MD. Trauma, Posttraumatic Stress Disorder, and Physical Illness: Findings from the General Population. Psychosomatic Medicine 71(9):p 1012-1017, November 2009. | DOI: 10.1097/PSY.0b013e3181bc76b5 ↩︎
  30. Spitzer, Carsten MD; Barnow, Sven PhD; Völzke, Henry MD; John, Ulrich PhD; Freyberger, Harald J. MD; Grabe, Hans Joergen MD. Trauma, Posttraumatic Stress Disorder, and Physical Illness: Findings from the General Population. Psychosomatic Medicine 71(9):p 1012-1017, November 2009. | DOI: 10.1097/PSY.0b013e3181bc76b5 ↩︎