It's when you know you're gonna do something that you shouldn't but you do it anyways, like dropping something even though you had no intention of dropping it but the thought of dropping it crossed your mind and you consciously decided not to drop the thing but you did anyways.
The thought process is pretty much "I know I shouldn't do this but I'm going to even though I don't want to". Might be a medical term, maybe there isn't even a word for it.
Best use I can think of is: "The patient has been suffering from ____ for a long time"
I'm seeking the word or definition for the act of doing said thing even though you don't want to and made a conscious decision not to but still do.
It's not a compulsion, but more of a momentary dissonance(?) between your brain and your body about what to do. Not sure if this will clarify it enough.