From what I have read, Terry, there is some crossed wiring in the brain, that leaves us susceptible to random anxiety attacks. After the first surprise attacks, we become fearful of them. It's fear of fear. Things like physical abuse, can trigger the first ones and then the fear of the fear takes over.
I hope that makes sense.
You could be right. I never had them until I had the first one many years ago and it was a doozy. I was hyperventilating and didn't know it until the paramedics told me. I know how to prevent that now but not the gut wrenching, sickening feeling I get. Luckily it doesn't happen as often now that I don't have to work but stress still triggers it, that's why I need to move to a more suitable environment where it is quiet.