Causes may be:

  • Low levels of a chemical called hypocretin in the body
  • Problems that affect the central nervous system, such as multiple sclerosis and birth defects of the brain

Risk Factors

This problem often starts in people who are 10 to 20 years of age. Things that may raise the risk are:

  • Genetic factors, including having other family members with the disorder
  • A history of certain strep infections



People with the disorder have 1 or more of these problems:

  • Excessive daytime sleepiness
  • Muscles that go limp without warning when a person is awake (often triggered by strong emotions like laughter)
  • Brief times when the person cannot move while waking up or falling asleep
  • Sudden attacks of sleep that may happen many times during the day without control
  • Vivid dreams that happen while waking up or falling asleep
Brainstem—Area of Brain Related to Alertness
GM00010 97870 brainstem.jpg
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The doctor will ask about your symptoms and health history. A physical exam may be done.

Tests that may be done to diagnose the disorder include:

  • Multiple sleep latency test (MSLT) to assess daytime sleepiness
  • Polysomnography to study brain waves and how the body works during sleep
  • A lumbar puncture to measure the level of hypocretin around the brain and spinal cord



There is no cure. The goal of treatment is to manage symptoms. Options are:

  • Medicines to treat excessive daytime sleepiness and sudden loss of muscle control
  • Lifestyle changes, such as taking short naps during the day and using good sleep hygiene


There are no guidelines to prevent this problem.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.