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What Is Kleine-Levin Syndrome?

Excessive Sleeping in Teens May Represent Rare Disorder


Updated February 20, 2014

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What Is Kleine-Levin Syndrome?
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Teens often sleep more than adults, but some of these youth may have an extremely rare neurological disorder that causes recurrent episodes of excessive sleep called Kleine-Levin syndrome. What is Kleine-Levin syndrome and what makes it unique?

Symptoms of Kleine-Levin Syndrome

Kleine-Levin syndrome is an extremely rare sleep disorder that involves recurrent episodes of excessive sleepiness called hypersomnolence. There may be associated difficulties thinking and eating.

During the episodes of excessive sleepiness, the affected person may sleep for hours, days, and even weeks at a time. They are often difficult to awaken and may lose weight as they are unable to stay awake long enough to eat. When they do briefly awaken, they seem to be in an almost dream-like state.

The episodes of excessive sleepiness may last from three days to three weeks and then subside. These episodes may occur from every six months to a year, and between the episodes the affected person is normal. There may be numerous episodes, often at least a dozen, and most symptoms stop after four to eight years. Kleine-Levin syndrome may sometimes last for decades.

There may be some other unusual symptoms associated with the disorder, including:

  • Hypersexual behavior
  • Compulsive behavior
  • Depression
  • Confusion
  • Apathy (lack of interest)
  • Hallucinations

Who Gets Kleine-Levin Syndrome?

There are only a few thousand cases of this syndrome known in the world. The average age of onset of Kleine-Levin syndrome is 16.9 years, but it may first affect children as young as 8 or as old as 25. More than 81% of cases occur during the second decade of life and boys are affected twice as often as girls. Girls, however, tend to have longer disease courses. There is a possible predisposition among Jewish individuals.

What Causes Kleine-Levin Syndrome?

The cause of Kleine-Levin syndrome is not known. During the hypersomnolent episodes, there may be abnormalities noted on polysomnography. For instance, there may be decreased sleep efficiency, diffuse slowing of the EEG activity, and increased amounts of REM sleep.

The condition often occurs randomly, but there may be an autoimmune trigger. Approximately 43% of cases are preceded by an infection or fever.

Treatment of Kleine-Levin Syndrome

The only medication to show a benefit in the treatment of Kleine-Levin syndrome is the mood stabilizer lithium. This medication is often used to treat bipolar disorder. Other treatments that have not been shown to be helpful include electroconvulsive therapy, amphetamine stimulants, and seizure medications.


Arnulf, I et al. "Kleine-Levin syndrome: a systematic review of 186 cases in the literature." Brain. 2005;128(12):2763-2776.

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