I've definitely been through periods in my life that involved chronic sleep deprivation, due to work or school schedules. And I find that at some point, my body forces me to take a rest, usually by getting sick. If I'm well rested in the first place, I can handle a few nights of bad sleep without too much effect, though.
In university, it wasn't too bad, because I could crash between semesters and catch up. But once I started full time work, I lost that crash period - a typical vacation allocation for a junior worker is not enough to do that with.
My personal rhythm is moderate night owl, which can slip to extreme night owl if I let myself. I am pretty good at staying up late, but I simply cannot fall asleep when I'm not tired, even with drugs, so going to bed early is generally not a possibility.
About once or twice a year I end up with a work related trip which involves missing a night of sleep, due to time zone issues. One trip, out of a week (so seven nights), I got six 'nights' of sleep. But on one day my night of sleep was from 7am to 11am, then getting up, then going to bed at 10 pm to try to sleep before getting up at 6am to catch a flight. Unfortunately, issues of flight times and work schedules make this necessary. By the end of the trip, I felt like death warmed over, and it took a good week to get back to normal, even though jet-lag doesn't affect me very much.