Alex has a strange sleep problem. He calls it "oversleeping" that has developed shortly after antidepressant Lexapro, during which he could sleep for up to 15 hours at a time.  Eventually he got off of the antidepressant, and a few months later developed a strange symptom - after sleeping even a little bit, he would feel overslept, would feel as if his head is heavy, he'd have trouble concentrating, become very irritable, and just not himself.  So he stays awake as long as possible, preventing himself from falling asleep, until he literally passes out, and even then he tries to prevent himself from sleeping more than a few hours at a time.  This worried me, so I advised him to try to get his sleep on track by sleeping normal hours.  This however, did not work, and same symptoms came back.  Doctor's insight would be very much appreciated.