Trauma is not just a psychological experience. It is a biological one. And one of the places it tends to live in the body, long after the original events have passed, is the gut.
If you have a history of difficult or traumatic experiences — and also have IBS or chronic digestive symptoms — you are not imagining the connection. The research linking adverse experiences to gut dysfunction is substantial, and it is changing how clinicians understand and treat digestive disorders.
What Trauma Does to the Gut-Brain System
Traumatic experience — particularly when it is early, prolonged, or relational — produces lasting changes in the systems that regulate the body’s stress response. The HPA axis, which governs cortisol release, becomes dysregulated. The autonomic nervous system, which controls the balance between sympathetic activation and parasympathetic rest, loses its flexibility. The nervous system learns to stay alert — monitoring for threat, braced for harm — in ways that persist long after the dangerous circumstances have ended (van der Kolk, 2014).
The gut-brain axis runs directly through these same systems. When the HPA axis is dysregulated by trauma, the gut receives altered stress signals. When the autonomic nervous system loses its flexibility, digestion — a fundamentally parasympathetic function — suffers. When the nervous system is chronically primed for threat, the enteric nervous system becomes hypersensitive, interpreting ordinary gut sensations as alarming (Mayer et al., 2023).
Research looking specifically at adverse childhood experiences (ACEs) and IBS finds that early life adversity significantly increases both the risk of developing IBS and the severity of symptoms when it does develop, likely through these lasting alterations to the stress-response and gut-brain communication systems (Dong et al., 2025). A striking illustration of the biological specificity of this relationship: IBS heritability is only about 5.8 percent, meaning that genetics accounts for very little of IBS risk, while environmental factors — including traumatic experience — account for the vast majority (Mayer et al., 2023).
The Body Remembers What the Mind Has Moved On From
One of the most disorienting aspects of trauma and the gut is the timing disconnect. People often describe their IBS symptoms worsening years after the difficult events that shaped them — long after they have processed things cognitively, moved on with their lives, and feel like they have “dealt with” what happened.
This is because the gut does not operate on cognitive time. It operates on nervous system time. The body’s threat-response patterns, once established, do not automatically update when circumstances change or when understanding is reached intellectually. They update through the nervous system — through repeated experiences of safety, through somatic and relational healing, through the kind of work that communicates to the body, not just the mind, that the danger has passed.
This Is Not About Blame — It Is About Possibility
Understanding the trauma-gut connection is not about assigning blame for your IBS to your past, or to the people or circumstances that shaped it. It is about expanding the picture of what is actually going on — and therefore what kinds of help are available.
If your IBS has been treated as a purely digestive problem, and the standard approaches have helped only partially, the nervous system layer may be what has been missing. Gut-directed therapies that address nervous system dysregulation — including gut-directed CBT and gut-directed hypnotherapy — have strong evidence for IBS symptom improvement even in populations where psychological complexity is high (Lackner et al., 2018; Adler et al., 2025). Trauma-informed, somatic approaches to gut-brain therapy address the deeper layer: the body’s stored experience of threat, and what it takes for that experience to be metabolized rather than carried indefinitely.
Your gut is not failing you. It is carrying something. And there is real help for that.
About the author
Susan Liddy, MAMFT is a GI Psychotherapist and doctoral candidate in Integrative Health, specializing in nervous system-informed care for IBS and disorders of gut-brain interaction. Georgia residents are welcome to schedule a free consultation at www.susanliddy.com.
For educational purposes only. Not medical or psychological advice. © 2026 Susan Liddy, MAMFT
References
Adler, E. C., Levine, E. H., Ibarra, A. N., Boparai, E. S., Hung, Y.-Y., McCrary, Q. D., & Lee, J. K. (2025). Gut-directed hypnotherapy for irritable bowel syndrome: A systematic review and meta-analysis. Neurogastroenterology & Motility, 37(4), e70037. https://doi.org/10.1111/nmo.70037
Dong, T. S., Peters, K., Gupta, A., Jacobs, J. P., & Chang, L. (2025). Multi-omics analysis reveal clinical-gut-brain interactions in female IBS patients with adverse childhood experiences. Biology of Sex Differences, 16(1), 18. https://doi.org/10.1186/s13293-025-00757-w
Lackner, J. M., Jaccard, J., Keefer, L., Brenner, D. M., Firth, R. S., Gudleski, G. D., Hamilton, F. A., Katz, L. A., Krasner, S. S., Ma, C.-X., Radziwon, C. D., & Sitrin, M. D. (2018). Improvement in gastrointestinal symptoms after cognitive behavior therapy for refractory irritable bowel syndrome. Gastroenterology, 155(1), 47–57. https://doi.org/10.1053/j.gastro.2018.03.063
Mayer, E. A., Ryu, H. J., & Bhatt, R. R. (2023). The neurobiology of irritable bowel syndrome. Molecular Psychiatry, 28(4), 1451–1465. https://doi.org/10.1038/s41380-023-01972-w
van der Kolk, B. A. (2014). The body keeps the score: Brain, mind, and body in the healing of trauma. Viking.
