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  • Cynthia M. Johnson, MA
Publication Type:




Narcolepsy is a sleep disorder that results in excess sleepiness during the day. Sudden attacks of sleep can also happen while driving, talking, or working.

There are two types. People with type 1 have muscle weakness and low levels of a chemical called hypocretin in the body. People with type 2 do not have muscle weakness and have normal levels of hypocretin.


Causes may be:

  • Low levels of hypocretin in the body (type 1)
  • 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


The main symptom is excessive daytime sleepiness even when a person has good quality sleep at night. Other problems may be:

  • 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.

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The doctor will ask about 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, such as anti-depressants and stimulants
  • Lifestyle changes, such as taking short naps during the day and using good sleep hygiene


There are no guidelines to prevent this problem.





  • Narcolepsy. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/narcolepsy.
  • Narcolepsy. National Sleep Foundation website. Available at: https://www.sleepfoundation.org/narcolepsy.
  • Narcolepsy fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: https://www.ninds.nih.gov/narcolepsy-fact-sheet.


  • Mark S. Itzkowitz, MD, JD
Last Updated:

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.