interesting... what makes it interesting, is.. i too zone out under stress. it's like i'm there one moment, then all of the sudden i just disconnect, like someone flipped a switch. the looks i get when i do come back though . unfortunately i don't have an answer to this, but would like to know the answer as well.
I was diagnosed with A.D.D. as a child. Don't remember if i took that medication though. hopped between a few different medications when i was little. never abused any of them, but i did become mildly addicted/dependent on one of them, and i forget which one it was.
*edit*
i should note that I've not been on medication since I was in 6th grade. my high school GPA confirms it,