Kleine-Levin syndrome is a rare disorder is characterized by recurring but reversible periods of excessive sleep (up to 20 hours per day).

Kleine-Levin syndrome primarily affects adolescent males (approximately 70 percent of those with Kleine-Levin syndrome are male).

Symptoms may be related to malfunction of the hypothalamus and thalamus, parts of the brain that govern appetite and sleep.

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. During episodes, the following may be observed:

• Excessive food intake
• Irritability
• Childishness
• Disorientation
• Hallucinations
• An abnormally uninhibited sex drive

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. Episodes eventually decrease in frequency and intensity over the course of eight to 12 years.

There is no definitive treatment for Kleine-Levin syndrome and watchful waiting at home, rather than pharmacotherapy, is most often advised. Stimulant pills, including amphetamines, methylphenidate, and modafinil, are used to treat sleepiness but may increase irritability and will not improve cognitive abnormalities. Because of similarities between Kleine-Levin syndrome and certain mood disorders, lithium and carbamazepine may be prescribed and, in some cases, have been shown to prevent further episodes. This disorder should be differentiated from cyclic re-occurrence of sleepiness during the premenstrual period in teen-aged girls, which may be controlled with birth control pills. It also should be differentiated from encephalopathy, recurrent depression, or psychosis.