The moment this sort of hypothesis turns up I always crow cite your sources. There's very little academic honesty in the area of psychology, a lot of it being coming up with an idea that sounds about right, finding a minuscule dataset to fit to it and then waving hands around profusely about how it's a breakthrough. Tenuous correlation it is mostly.
Yes it's tough, this area of medicine is historically neglected. That's starting to change though. Here are some interesting sources:
1. Neuroscience of dissociation: Bramson, B., Meijer, S., van Nuland, A., Toni, I., & Roelofs, K. (2023). Anxious individuals shift emotion control from lateral frontal pole to dorsolateral prefrontal cortex. Nature Communications |, 14, 1234567890. https://doi.org/10.1038/s41467-023-40666-3
2. Using psychophysiologic treatment for long covid and back pain:
Donnino, M., Bs, P. H., Mehta Ba, S., Silverman Ba, J., Cabrera Ba, M. J., Yamin, J. B., Mph, B., Ma, R. T., Berg, K. M., Phd, R. E., & Grossestreuer, A. v. (n.d.). Title: Psychophysiologic symptom relief therapy (PSRT) for post-acute sequelae of COVID-19: a non-randomized interventional study. https://doi.org/10.1101/2022.10.07.22280732
and
Donnino, M. W., Thompson, G. S., Mehta, S., Paschali, M., Howard, P., Antonsen, S. B., Balaji, L., Bertisch, S. M., Edwards, R., Ngo, L. H., & Grossestreuer, A. v. (2021). Psychophysiologic symptom relief therapy for chronic back pain: a pilot randomized controlled trial. PAIN Reports, 6(3), e959. https://doi.org/10.1097/PR9.0000000000000959
and
Williams, A. C. de C., Fisher, E., Hearn, L., & Eccleston, C. (2020). Psychological therapies for the management of chronic pain (excluding headache) in adults. Cochrane Database of Systematic Reviews, 2020(8). https://doi.org/10.1002/14651858.CD007407.PUB4/MEDIA/CDSR/CD...
as well as a review looking at the connection between early childhood adversity and fibro
Varinen, A., Kosunen, E., Mattila, K., Koskela, T., & Sumanen, M. (2017). The relationship between childhood adversities and fibromyalgia in the general population. Journal of Psychosomatic Research, 99, 137–142. https://doi.org/10.1016/J.JPSYCHORES.2017.06.011
there's a lot out there but year the research is still in it's infancy ...