What is Kleine-Levin Syndrome?

Kleine-Levin syndrome, also sometimes referred to as Sleeping Beauty syndrome, is a rare neurological disorder that involves episodes of excessive sleep and altered behavior.

During these episodes, affected individuals often sleep for up to 20 hours per day and are unable to meet work and social demands of their everyday life. These episodes usually last for a few weeks, then the individual returns to near perfect health until the initiation of the next episode.

The syndrome usually presents in adolescence, but symptoms can begin at any age, from childhood to adulthood. It affects more males than females, with approximately 70% of Kleine-Levin patients being male. However, the females that are affected tend to have a longer course of disease than men.


An individual with Kleine-Levin syndrome experiences periodic episodes of altered sleep habits and behaviors. Between these episodes, patients do not notice any symptoms and appears to be in otherwise perfect health.

During an episode of Kleine-Levin syndrome, the patient becomes very drowsy and sleeps throughout the night and most of the day, known as hypersomnolence. In many cases, individuals sleep continuously and wake up only for short periods to eat or go to the bathroom, which can disrupt their professional or social life considerably. Characteristic symptoms may include:

  • Childlike or “spacey” demeanour
  • Confusion and disorientation
  • Lethargy and fatigue
  • Lack of emotions and focus
  • Photosensitivity and phonosensitivity
  • Compulsive hyperphagia (food cravings)
  • Hyper-sexuality

The symptoms during the episode may last for a few days but can continue for several months in some cases, inhibiting normal daily activities. They then resolve spontaneously for a period of time until another episode begins suddenly some time later.


The diagnosis of Kleine-Levin syndrome is usually delayed for several years after the presentation of the first episode, as initially the symptoms are attributed to other sleeping disorders. It is the characteristic pattern of Kleine-Levin syndrome, which occurs in distinct periodic episodes, that sets the condition apart from other sleeping disorders.

The diagnostic criteria of Kleine-Levin syndrome are recurrent episodes of severe hypersomnia (2-31 days), interspersed with long periods of regular sleep habits, cognition mood and behavior. During episodes, they will also exhibit at least one of:

  • Cognitive abnormalities (e.g. confusion or hallucinations)
  • Abnormal behavior (e.g. irritability or aggression)
  • Binge eating
  • Hyper-sexuality

The diagnosis of Kleine-Levin syndrome should be differentiated from other cyclic hypersomnia disorders, such as premenstrual syndrome in adolescent women, and encephalopathy, recurrent depression and recurrent psychosis.

Management of Episodes

There is no specific treatment for the prevention of Kleine-Levin syndrome episodes and watchful waiting is usually the recommended approach, rather than pharmacotherapy.

During an episode, medications may be recommended to manage excessive sleepiness symptoms. This may include stimulant medications, such as modafinil, amphetamines or methylphenidate. However, these medications are not able to effectively improve cognitive abnormalities are associated with side effects such as irritability and other mood changes.

Other pharmacotherapy options that are sometimes recommended include lithium and carbamazepine. These drugs were suggested for use due to the similarity in symptoms between Kleine-Levin syndrome and other mood disorders, and may be effective to prevent or prolong the period before the initiation of another episode.

Additionally,  some alternative pharmacological treatments are currently being used to test the response of an individual. This includes the anticonvulsant medication, phenytoin, which has appeared to precipitate a positive response in some patients.


  • http://klsfoundation.org/what-is-kleine-levin-syndrome/
  • http://www.ninds.nih.gov/disorders/kleine_levin/kleine_levin.htm
  • http://rarediseases.org/rare-diseases/kleine-levin-syndrome/
  • http://brain.oxfordjournals.org/content/128/12/2763

Further Reading

  • All Kleine-Levin Syndrome Content

Last Updated: Aug 23, 2018

Written by

Yolanda Smith

Yolanda graduated with a Bachelor of Pharmacy at the University of South Australia and has experience working in both Australia and Italy. She is passionate about how medicine, diet and lifestyle affect our health and enjoys helping people understand this. In her spare time she loves to explore the world and learn about new cultures and languages.

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