Mine happened most often when I was in my head, in "fantasy" thinking about therapy and trying to work things out, etc. I wouldn't know it was coming or be able to do anything about it either, it would just be an "insight" and all the ruckus that would start would be me following it to its logical conclusion while I was protesting, while I was mentally "screaming" in terror and trying to think/run in opposite directions, etc. :-) It was just an "overload" of my thought and feeling processes.

The more "willing" I was to explore difficult topics in therapy and the more comfortable I got with that, seemed to make it happen less. The whole "when" it happened was a clue. My T didn't say much about it, I had told her about it but she'd never "seen" it but then understood. We were able to talk together about "that" one and that was helpful, putting it into words. I think it's so intense because we don't have the words for it? It's kind of like a flashback in that sense except it's a thought rather than a memory? But the more I could express myself, get stuff out, the less it happened. So, must just be a visual versus "word" way of communicating with yourself? If you think about it :-) all thoughts use words. But if we don't have the words, how else is your subconscious going to talk to you? Has to use visual/"take over" your brain which I could see would take over one's whole nervous system; kind of like at night when you're dreaming, you get "locked" in then too but can twitch and occasionally kick, etc. Think of a dog dreaming :-)