I'm looking at FND as I would at ME/chronic fatigue syndrome as a description of symptoms instead of a diagnosis. The equivalent would be asking a GP how many patients they'd seen with a rash last week. That would tell you how many people they'd seen with a rash but not what had caused the rash. With a rash, the GP can also generally make a diagnosis, whether it is something terribly serious like meningitis or minor like an allergy to nickel in a necklace. Likewise, FND symptoms may be quite minor and transient or serious enough to be life-threatening and so far it seems to be a secret what causes them. I think it is likely that in some people it is viral, in others bacterial, in others scarring after physical trauma or infection. It is well known that long-term stress causes a decrease in the immune system increasing the likelihood of infection and a decrease in the speed of recovery which would explain why people can get this after difficult life events. Given the complexity of the nervous system, symptoms could result from inflammation within the neurone, problems with neurotransmitters at each end or with the insulation. Each of these may cause similar symptoms but will be at the molecular level so difficult to measure. Hopefully, with increased research and better tools for testing at least some patients will get some answers and subsequently some effective treatment. Good luck to everyone, I am slowly recovering and can walk again.