FND and PTSD

I was diagnosed with Functional Neurological Disorder (FND) at Mayo. They explained to me the issue with the Sympathetic Nervous System that is common with FND, which has been one of the biggest challenges I've faced. I've read a bit about PTSD, and it seems to be, if not the same thing, functionally the same. My question is sort of a "chicken and egg" question - is a traumatic event a factor in causing the FND, or is the sympathetic nervous system problem a symptom of FND? Is there a relationship between FND and PTSD? I started practicing Transcendental Meditation (TM) because I read that it has been the most effective treatment for people with PTSD, and I have found it does benefit me greatly. I faithfully meditate twice daily, and my quality of life has improved greatly since I began this practice.