Psychological Trauma and Dementia: Associations, Mechanisms, and What Remains Insufficiently Understood

Written By: Juliana Morsello

Edited By: Noor Amina

Designed by https://www.freepik.com/ 

Introduction

Imagine sustaining a physical wound and feeling the ache of pain without knowing how deep the cut truly runs. You sense the hurt, yet have no clarity about the damage beneath the surface. This is the nature of trauma in the brain. Traumatic experiences leave their mark like tattoos, etched into neural tissue. As we endure a tattoo session, we cannot fathom how far our new ink spreads or how deeply it seeps into us.

For some, the endurance of trauma steps loudly into life, announcing itself unwelcomingly as disconnection from others or as a struggle to regulate emotions. For others, it arrives as memory difficulties, where small lapses grow more frequent with age, until one day the pattern is written into a diagnosis such as dementia. Often, that diagnosis is attributed to genetics or other influences. In reality, trauma, or its interplay with those factors, may shape the mind in ways we are only beginning to understand.

In this article, I will discuss trauma and its influence on cognition, along with its relationship to dementia and Alzheimer’s disease. I will also discuss the brain mechanisms potentially underlying these associations and the critical gaps that future research should address.

Trauma and Cognition

What do we currently know about psychological trauma and its relationship to cognitive processes such as memory? There is substantial evidence suggesting that trauma is related to poor cognition. Exposure to a greater number of traumatic events generally corresponds to more severe cognitive deficits, and specific types of trauma may have both distinct and similar effects on cognition. For example, in a study published by Cambridge University, researchers found that complex trauma, defined as exposure to multiple traumatic events during childhood, was associated with poorer cognitive functioning (e.g., processing speed, spatial working memory) in early adulthood compared to no trauma or non-complex trauma exposure (Lewis et al., 2021). Additionally, while childhood trauma in general has been linked to worse cognitive performance (Petkus et al., 2018), with abuse potentially leading to slower responses, it is childhood neglect that shows an association with long-term deficits in executive functioning and memory (Wang et al., 2024).

Trauma and Risk for Dementia

With diagnoses of several types of dementia on the rise, it is important to better understand the factors that may increase the likelihood of experiencing dementia symptoms. In a meta-analysis of seven studies, Severs et al. (2023) found that traumatic life events (TLE), such as experiencing or witnessing “actual or threatened death, significant injury, or sexual violence,” were linked to an increased risk of dementia in war/Holocaust survivors and victims of childhood abuse. 

In light of these findings, we may ask ourselves what trauma disorders are implicated in dementia risk. In another meta-analysis, Bougea et al. (2020) reported that Post Traumatic Stress Disorder (PTSD), which is a severe, trauma-related condition that may develop after witnessing a TLE, appears to increase one’s odds of developing dementia. However, this article does not provide insight into which specific types of dementia (e.g., vascular, Alzheimer’s) are most strongly related to PTSD.

Trauma and Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common type of dementia, yet this neurodegenerative disease remains incurable and shrouded in complexity. Despite decades of research, many factors that have been indicated as underlying AD, including those that are psychosocial in nature, are still not fully understood. However, it has been proposed is that adverse childhood experiences (ACEs), such as sexual abuse and parental abuse, may contribute to the onsent of AD or even amplify the risk of other known factors in its development (like depression and neuroinflammation) (Corney et al., 2022). 

Though this extends beyond the focus of this article, it is worth noting that trauma experienced while living with AD may also influence the course of the condition. This idea is reflected in Tom Kitwood’s dialectical theory of dementia, which challenged the premise that neurological impairment is the sole determinant and instead proposed that psychosocial factors mix with neurology to create distinct clinical trajectories (Kitwood, 1990). Accordingly, since trauma is a psychosocial stressor, it is important to consider not only how early-life trauma increases the risk of developing AD later in life, but also how trauma experienced during AD may influence disease progression.

The Neuroscience Behind PTSD and Dementia

Several brain regions and molecular mechanisms, whose impairment is implicated in the development of PTSD, are also known contributors to Alzheimer's disease. Although there is a dearth of literature on the neurobiological mechanisms linking PTSD and dementia, research reveals a parallel between the brain changes seen in these conditions. For example, neuroimaging research shows that temporal lobe areas such as the hippocampus and amygdala, which are essential for forming memories, regulating emotions, and processing stress, show reduced volume in those with PTSD (Araújo et al., 2023). In Alzheimer’s disease, early atrophy, or deterioration, is also seen in these regions and spreads to other areas, such as the prefrontal cortex, contributing to the progression of moderate cognitive decline, or what is referred to as Mild Cognitive Impairment (MCI), to full-blown Alzheimer’s disease. Essentially, what this overlap suggests is that PTSD may set neurobiological changes in motion that create a vulnerable foundation on which Alzheimer’s processes can more readily progress. 

Earlier in the article, I discussed trauma research largely related to children. However, other work that can additionally inform us about PTSD and the brain is veteran research.  It was previously found that U.S. veterans with PTSD were twice as likely to be diagnosed with dementia (Yaffe et al., 2010), and a potential explanation of this finding relates to dysfunction of the HPA axis. To clarify, the HPA axis is our stress response system. When we’re stressed, this axis releases what we commonly refer to as the stress hormone, or cortisol. In individuals with PTSD, cortisol levels can be chronically elevated, which can slowly break down connections in the brain that are essential for cognitive functions (Prieto et al., 2023), including memory, and accelerate the development of Alzheimer’s disease (Justice, 2018).

Current Gaps in the Literature

Although the literature has provided evidence for the correlation between trauma and dementia, as well as suggested the ways in which biology may influence this relationship, there is still more work to be done. Notably, there appears to be a significant lack of research on the various types of dementia and their potentially unique or similar associations with trauma. In the same vein, future work should prioritize better understanding of how several groups of people, who have experienced distinct subtypes of trauma, for varying durations, show specific markers or signs related to dementia. This could be pursued through biomarker research that examines how the signs that predict dementia differ across demographic groups or through longitudinal studies tracking and comparing their cognitive performance over time. In doing so, medical and clinical teams can better understand what specific risk factors should be on their radar depending on the individual patient.

Additionally, it should be further researched how different consequences of trauma, such as sleep disturbances or even depressive symptomatology, are particularly related to dementia. Perhaps this can be done in a study where these participants are compared to those who do not have trauma but experience similar issues. By being able to better distinguish these patterns, we can gain a clearer grasp of how specifically trauma impacts dementia risk.

Conclusion

When thinking about why this all matters, it is difficult and sad to realize how many of us already understand it firsthand. Unfortunately, children and adults in the U.S. are undoubtedly facing numerous opportunities for trauma, whether through the rise of technology and cyberbullying or the increasing number of school shootings. Because of this, we know exactly why this research matters: to protect the children of today and tomorrow, whose childhood trauma can have immediate and long-term consequences, impacting the very minds they should be able to use for learning but instead may struggle with complications. It also matters for protecting our loved ones who may be at risk for Alzheimer’s disease, whether due to genetics or other influences. The point is, everyone knows someone, close or distant, who has or will experience trauma, and by better understanding its consequences, even beyond dementia, we can learn how to support them more effectively.

References

Araújo, D., Sair, H. I., Peters, M. E., Carvalho, A. F., Vivek Yedavalli, Solnes, L. B., & Luna, L. P. (2023). The association between post-traumatic stress disorder (PTSD) and cognitive impairment: A systematic review of neuroimaging findings. Journal of Psychiatric Research, 164, 259–269. https://doi.org/10.1016/j.jpsychires.2023.06.016

Bougea, A., Anagnostouli, M., Angelopoulou, E., Spanou, I., & Chrousos, G. (2020). Psychosocial and Trauma-Related Stress and Risk of Dementia: A Meta-Analytic Systematic Review of Longitudinal Studies. Journal of Geriatric Psychiatry and Neurology, 35(1), 24–37. https://doi.org/10.1177/0891988720973759

Corney, K. B., West, E. C., Quirk, S. E., Pasco, J. A., Stuart, A. L., Manavi, B. A., Kavanagh, B. E., & Williams, L. J. (2022). The Relationship Between Adverse Childhood Experiences and Alzheimer’s Disease: A Systematic Review. Frontiers in Aging Neuroscience, 14. https://doi.org/10.3389/fnagi.2022.831378

Justice, N. J. (2018). The relationship between stress and Alzheimer’s disease. Neurobiology of Stress, 8(1), 127–133. https://doi.org/10.1016/j.ynstr.2018.04.002

Kitwood, T. (1990). The Dialectics of Dementia: With Particular Reference to Alzheimer’s Disease. Ageing and Society, 10(02), 177–196. https://doi.org/10.1017/s0144686x00008060

Lewis, S. J., Koenen, K. C., Ambler, A., Arseneault, L., Caspi, A., Fisher, H. L., Moffitt, T. E., & Danese, A. (2021). Unravelling the contribution of complex trauma to psychopathology and cognitive deficits: a cohort study. The British Journal of Psychiatry, 219(2), 448–455. https://doi.org/10.1192/bjp.2021.57

Petkus, A. J., Lenze, E. J., Butters, M. A., Twamley, E. W., & Wetherell, J. L. (2018). Childhood Trauma Is Associated With Poorer Cognitive Performance in Older Adults. The Journal of Clinical Psychiatry, 79(1). https://doi.org/10.4088/jcp.16m11021

Prieto, S., Nolan, K. E., Moody, J. N., Hayes, S. M., & Hayes, J. P. (2023). Posttraumatic stress symptom severity predicts cognitive decline beyond the effect of Alzheimer’s disease biomarkers in Veterans. Translational Psychiatry, 13(1), 1–9. https://doi.org/10.1038/s41398-023-02354-0

Severs, E., James, T., Letrondo, P., Lovland, L. R., Marchant, N. L., & Naaheed Mukadam. (2023). Traumatic life events and risk for dementia: a systematic review and meta-analysis. BMC Geriatrics, 23(1). https://doi.org/10.1186/s12877-023-04287-1

Wang, M., Wei, J., Dou, Y., Wang, Y., Fan, H., Yan, Y., Du, Y., Zhao, L., Wang, Q., Yang, X., & Ma, X. (2024). Differential association between childhood trauma subtypes and neurocognitive performance in adults with major depression. BMC Psychiatry, 24(1). https://doi.org/10.1186/s12888-024-06226-9

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