Kleine-Levin syndrome is a rare disorder that causes recurring periods of excessive drowsiness and sleep (up to 20 hours per day). Symptoms, which may last for days to weeks, include excessive food intake, irritability, disorientation, lack of energy, and hypersensitivity to noise. Some patients may also experience hallucinations and an abnormally uninhibited sex drive. Affected persons are normal between episodes, although depression and amnesia may be noted temporarily after an attack. It may be weeks or more before symptoms reappear. Onset is typically around adolescence to the late teens. The disorder is 4 times more common in males than in females. Symptoms may be related to malfunction of the hypothalamus, the part of the brain that governs appetite and sleep.

There is no definitive treatment for Kleine-Levin syndrome. Stimulants, including amphetamines, methylphenidate and modafinil, administered orally, are used to treat sleepiness. Because of similarities between Kleine-Levin syndrome and certain mood disorders, lithium and carbamazepine may be prescribed. Responses to treatment have often been limited. This disorder needs to be differentiated from cyclic re-occurrence of sleepiness during the premenstrual period in teenaged girls that may be controlled with birth control pills.

The disorder appears to be benign and does not impact on intellect or physical function. Symptoms usually improve or disappear with advancing age.

Prepared by the National Institutes of Health