Kleine-Levin Syndrome

Kleine-Levin syndrome (KLS) is a rare disorder that makes people sleep for a long time. Sleeping for up to 20 hours a day and exhibiting unusual behavior are hallmarks of episodes seen by those diagnosed with KLS.

Last Updated: February 25, 2024

The occurrence of Kleine-Levin syndrome occurs rarely. As much as 2% of the population may be affected each year. Adolescent boys are disproportionately affected (approximately 70 percent of those with Kleine-Levin syndrome are male).

Early adolescence is a common onset age, and symptoms often return more frequently than once a year. Symptoms included are the following:

  • Constant drowsiness and inability to concentrate
  • Increased hunger (hyperphagia)
  • Enhanced sexual desire (hypersexuality)
  • Hallucinations
  • Modifications in temperament or conduct
  • Anxiety or depression
  • Loss of memory or the ability to think clearly.

When these signs and symptoms last for more than two days, it is considered an episode. Episodes of KLS might last anywhere from a few days to a couple of weeks.

People with KLS generally have difficulty recalling specific details from an episode. Because of their extreme tiredness, they can only wake up briefly during an episode to eat or use the restroom.

After an incident, they will return to a normal state, showing no signs of the disorder other than temporary memory lapses. 

Kleine-Levin syndrome is hard to figure out. There is no one test that can tell if someone has KLS. Doctors determine if someone has KLS by ruling out other conditions with similar symptoms. 

Some tests that providers may offer are:

  • Sleep test to find out how much electricity is going on in a patient's brain
  • Memory tests
  • Blood work-up
  • Imaging tests like an MRI.


There is currently no cure for Kleine-Levin syndrome; patient monitoring at home is recommended instead of medication. Pills like amphetamines, methylphenidate, and modafinil, which are stimulants, are used to treat sleepiness. 

Lithium and carbamazepine are commonly administered for Kleine-Levin syndrome due to their similarities to mood disorders. In some cases, lithium and carbamazepine have been shown to stop further episodes. When teenage girls experience sleepiness during their premenstrual periods, doctors prescribe birth control pills to control the symptom. 

Since the cause of Kleine-Levin syndrome is unknown, there is no way to stop it. If parents are planning to have a child and are concerned about the possibility of passing on a genetic condition, they should discuss genetic testing with their doctor.



National Institute of Neurological Disorders and Stroke (2022). Kleine-Levin Syndrome. Retrieved December 19, 2022, from https://www.ninds.nih.gov/health-information/disorders/kleine-levin-syndrome


Cleveland Clinic (2022). Kleine-Levin Syndrome. Retrieved December 19, 2022, from https://my.clevelandclinic.org/health/diseases/23484-kleine-levin-syndrome

Last Updated: February 25, 2024