That is the point of the study, but in my non-scientific opinion it seems like a very poorly crafted study. Nobody is going to have issues with attention/motiv

That is the point of the study, but in my non-scientific opinion it seems like a very poorly crafted study. Nobody is going to have issues with attention/motivation during the one, short task they were assigned at some study. It's a very novel, motivating environment. And then of course if you're feeling the effects of a new drug, you'll be "off" a bit. This doesn't really prove anything about kids who take it for a few nights during exam week to study.