Question: What is (are) Kleine-Levin Syndrome ?
Answer: Kleine-Levin syndrome is a rare disorder that primarily affects adolescent males (approximately 70 percent of those with Kleine-Levin syndrome are male). It is characterized by recurring but reversible periods of excessive sleep (up to 20 hours per day). Symptoms occur as "episodes," typically lasting a few days to a few weeks. Episode onset is often abrupt, and may be associated with flu-like symptoms. Excessive food intake, irritability, childishness, disorientation, hallucinations, and an abnormally uninhibited sex drive may be observed during episodes. Mood can be depressed as a consequence, but not a cause, of the disorder. Affected individuals are completely normal between episodes, although they may not be able to remember afterwards everything that happened during the episode. It may be weeks or more before symptoms reappear. Symptoms may be related to malfunction of the hypothalamus and thalamus, parts of the brain that govern appetite and sleep.
Source: NINDS