Brian Robertson Brian Robertson

Can trauma cause Functional Neurological Disorder (FND)?

In short answer, it’s possible. The truth of the matter is we don’t fully know what causes it. There are many people with Functional Neurological Disorder or FND without any history of complex trauma. However, there are plenty of studies that show a correlation between complex childhood trauma and FND. In fact, one study found that there was a correlation between adverse childhood experiences and FND symptom severity. But before we answer whether trauma can cause FND, let’s first talk about what it is.

What is Functional Neurological Disorder?

‍ ‍Functional Neurological Disorder or FND is a neurological condition caused by changes in how the brain works. This is different than other neurological disorders that have changes in the brain structure itself. With FND, there are changes in connections between different brain regions. So think of it as different parts of the brain that aren’t communicating well with each other, rather than some actual physical alteration to the brain.

A person with FND can have a wide variety of physical and mental symptoms. A list of some possible symptoms may include:

  • Seizure-like episodes

  • Movement problems

  • Problems with cognitive functioning

  • Problems with vision or hearing

  • Dissociative symptoms

  • Involuntary muscle movements or muscle spasms

  • Numbness

  • Pain

  • Dysautonomic issues

It is important to note that FND usually requires a neurologist to diagnose. FND is hard to diagnose and usually requires alot of testing to rule out other conditions. Symptoms of FND can present at any time in life. However, it has been my personal experience as a therapist that when FND does have links to trauma, it often presents during times of high stress or when there is a trigger present to a past traumatic event. In alot of cases, the presentation of symptoms is not constant. Most symptoms are short-lived, going dormant until there is another trigger.

Interoception and FND

One thing FND seems to have an impact on is impairing interoception. Interoception is our brain and nervous system’s ability to sense, interpret, and integrate signals from inside our body. It is what allows us to have awareness of internal bodily states such as hunger, thirst, temperature, pain, etc. Interoception is also what allows us our body to maintain homeostasis by allowing the brain to communicate with other organs to maintain balance. For example, regulating our blood pressure as we stand up.

‍ ‍Interoception is also responsible for awareness of our thoughts and emotions. Think of it as the hub for interpreting and integrating all of the signals from our body, as well as our thoughts and emotions. This is especially true, as all emotions have a physical “felt sense” to them. In FND, sometimes symptoms can be brought on when experiencing intense emotions.

Interoception is controlled by a part of the brain called the insula or insular cortex. There are many things that can cause a disconnect or dysregulation between the insula and other areas of the brain, in turn effecting interoception. One thing that we know impacts the insula and our interoception process is trauma history. Does this mean that trauma causes FND? Not necessarily, but let’s examine what other links there are between trauma and FND.

The link between dissociative disorders and FND

‍ ‍There has been much research over the years which points to high comorbidity between FND and dissociative disorders. A dissociative disorder is an ongoing condition where a person’s consciousness becomes detached from certain experiences, thoughts, emotions, memories, sensations, or even aspects of their identity. As we know, dissociative disorders caused by extensive complex childhood trauma, usually starting at a young age. It was our brain’s way of adapting and surviving during those years of trauma and still continues because that part of out brain doesn’t realize the trauma is over with.

While it’s possible to have a dissociative disorder without FND and FND without a dissociative disorder, there is a high comorbidity between the two. In fact, comorbidity between FND and dissociative disorders may be as high as 80%. Dissociation is thought to be one of the main mechanisms causing loss of interoception and possibly alot of FND symptoms. One research study found that DES-II scores (used to measure dissociation) in FND were nearly as high as those in dissociative disorders.

Conclusions

While there is no way to definitively say whether or not trauma can be the origins or the cause of FND, there are some interesting links. It does make sense that complex trauma, already known to cause significant dissociative symptoms, could cause a change in how neurons connect with each other via through the impairment of interoception. We already know from the ACE (Adverse Childhood Experiences) study that complex trauma greatly increases our risk for developing all sorts of physiological issues. If some of those potential physiological issues are neurological in nature, then why couldn’t trauma be the cause? And if trauma is the cause, does it mean FND symptoms can be resolved? The only thing that I can say is that from my experience where there is a link between FND symptoms and someone’s trauma history, resolving the trauma can have a profound effect on the existing FND symptoms.

For more information on FND, check out https://fndhope.org/

Sources:

Campbell, M. C., Smakowski, A., Rojas-Aguiluz, M., Goldstein, L. H., Cardeña, E., Nicholson, T. R., Reinders, A. A., & Pick, S. (2022). Dissociation and its biological and clinical associations in Functional Neurological disorder: Systematic review and meta-analysis. BJPsych Open, 9(1). https://doi.org/10.1192/bjo.2022.597

National Institute of Neurological Disorders and Stroke. (2026, March 13). Functional neurologic disorder | National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/disorders/functional-neurologic-disorder

Paredes-Echeverri, S., Guthrie, A. J., & Perez, D. L. (2022). Toward a possible trauma subtype of functional neurological disorder: Impact on symptom severity and Physical Health. Frontiers in Psychiatry, 13. https://doi.org/10.3389/fpsyt.2022.1040911

Pick, S., Rojas-Aguiluz, M., Butler, M., Mulrenan, H., Nicholson, T. R., & Goldstein, L. H. (2020). Dissociation and interoception in functional neurological disorder. Cognitive Neuropsychiatry, 25(4), 294–311. https://doi.org/10.1080/13546805.2020.1791061

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