Kleine-Levin syndrome is a very rare neurological disorder. This disorder has recurring periods of excessive amounts of sleep. Anytime there is excessive or no sleep there is always altered behavior involved. Sadly to say, no one knows what causes this disorder.

When a patient is about to have an episode, they get very sleepy and sleep for most of that day and most of the night. This is actually called hypersomnolence. A person experiencing this sleeping disorder will wake up however, to eat and go to the bathroom.

When a patient with KLS is awake, their whole personality and lifestyle has changed.
These patients often appear childlike and/or spacey. They often appear lethargic, a complete lack of energy, they will experience confusion, a complete lack of emotion and disorientation.

These patients are usually bedridden, noncommunicative and tired. They are not able to take care of themselves. They do not go to work or attend school. Everything seems to be out of focus, and they are very sensitive to light and sound.

In some cases, these patients have massive food craving called compulsive hyperphagia. They also experience uninhibited hypersexuality in men and major depression has been reported in mostly women.

People with KLS go for years sometimes and never experience a symptom. When KLS does appear it is with little warning. Between episodes patients with KLS have no evidence of physical or behavior dysfunction and they appear to be in very good health.

There are lots of studies and research being done on Kleine-Levin Syndrome because the cause of it still remains unknown. Sometimes the treatment might have to be switched until they find one that works because of not knowing the cause of Kleine-Levin Syndrome.