It comes under neurological/ psychological category. It’s unknown what really causes it. It can manifest itself with neurological symptoms. My dad lost vision temporarily, could not walk, had tremors like a seizure and thought he was dying. The episodes aren’t as severe as they used to be. Here’s a link about it, if want to explore it. It contains an excellent explanation with example.
https://m.youtube.com/watch?v=g2RsGM_F9K4
(If this link is not allowed, I hope a mod will kindly remove it.)

I hope you are able to find answers about your condition.

For me it was seizures. Terrible seizures that looked real and it took a lot of testing to find out they weren't. No one was more surprised (and embarrassed!) than me. It was explained to me that when we don't handle our stress, our brain and body does. So, I did my therapy more humbled and got a lot out of it. Within 2 years I divorced my husband. (I was lonely in the same room as him!) I was trying to deny how much that relationship stressed me. Talk and marital therapy didn't work, and I tried. He didn't.

Since then I have realized that I have PTSD and have had it since I was 8 when I was with my mother in a car accident. She died, and I saw it. In my late 20s the repressed memory came back to me. So, PTSD changed my brain and behavior and it was a factor in my conversion disorder. I was diagnosed in my 30s with conversion disorder, after the repressed memory came back.
I am still in therapy, but I don't care how long it takes. I didn't get messed up easily so it makes sense it will take time. I am just grateful for therapy! Without it I would be in a far worse place! Now I am capable of being more honest with myself and responsible for myself.
Oh, and I quit having the seizures within 4 years. The divorce did a dramatic decrease in how many I had. It's been hard but I have never regretted the divorce.