Kleine-Levin Syndrome

What is Kleine-Levin syndrome?

Kleine-Levin syndrome is a rare disorder that primarily affects teenage males. Approximately 70 percent of people living with Kleine-Levin syndrome are male.

Symptoms include repeated but reversible periods of excessive sleep (up to 20 hours per day). Symptoms happen as "episodes," which typically last a few days to a few weeks, and may be related to malfunction of the parts of the brain that are in charge of appetite (hypothalamus) and sleep (thalamus).

Episodes often start suddenly and may include:

  • Flu-like symptoms
  • Overeating
  • Irritability
  • Childishness
  • Disorientation (not being sure where you are or what is happening)
  • Hallucinations (seeing or hearing things that are not there)
  • An abnormally unlimited sex drive

A person's mood can be depressed as a result of Kleine-Levin syndrome, but mood does not cause the disorder. People with the disorder are completely "normal" between episodes, but they may not be able to remember everything that happened in the episodes. It may be weeks or more before symptoms come back.

There is no sure treatment for Kleine-Levin syndrome. People with the disorder are often advised to carefully keep track of their symptoms (an approach called “watchful waiting”) at home, instead of treating the disorder with medicines. Stimulant pills, including amphetamines, methylphenidate, and modafinil, are used to treat sleepiness—but they may increase irritability and will not improve the person's ability to think and reason normally.

Because of similarities between Kleine-Levin syndrome and certain mood disorders, doctors may prescribe lithium and carbamazepine. In some cases, these drugs have prevented further episodes of the disorder.

Kleine-Levin syndrome is different from having repeated cycles of sleepiness during the premenstrual period in teenage girls. Those cycles may be controlled with birth control pills. The disorder is also different from encephalopathy (brain damage or brain disease), repeated depression, or psychosis (losing touch with reality).

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Learn About Clinical Trials
Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one help improve care for people with Kleine-Levin syndrome?

Consider participating in a clinical trial so clinicians and scientists can learn more about Kleine-Levin syndrome and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with Kleine-Levin syndrome at Clinicaltrials.gov.

Where can I find more information about Kleine-Levin syndrome?

The following organizations and resources help patients, families, friends, and caregivers of people living with Kleine-Levin syndrome:

National Heart, Lung, and Blood Institute (NHLBI)

National Organization for Rare Disorders (NORD)
Phone: 203-744-0100 or 800-999-6673; 844-259-7178 Spanish

National Sleep Foundation 
Phone: 703-243-1697