As a (recent) student, my problem has always been ego depletion/"lack of willpower", not so much a lack of intrinsic motivation. In the times I could be spending working, I feel too burnt out to do much other than watch TV/read HN. Starting in on reading a new book would be an insurmountable task, let alone doing productive work. And the worst thing is, I've never found anything that will give me back my "mojo" except time. So, I wait, and sometimes I get lucky and feel a burst of energy before the deadline long enough to start (continuing once started is a lot easier, but no matter how little I tell myself I need to do to get started, there's always a constant factor that can't be subdivided.)

I seem to get this way more often in winter, so it seems like it could be something like Seasonal Affective Disorder (i.e. clinical depression), but I'm never depressed, just unable to convince myself to take any other path than the easiest one (e.g. fast food instead of home cooking, Short stories instead of novels, video games instead of hobby coding, organizing my computer rather than cleaning my house, etc.)

I have a feeling quite a lot of students could describe their problems with motivation in a similar way. It's not "I don't want to study right now, there's nothing fun about that," but rather "I can't study right now, because I am curled up in a ball of stress-avoidance." (If these students had an escapist crutch, like drinking to excess, this is when they would be doing it.)