Diagnosis & treatment

What is narcolepsy? Narcolepsy definition and facts

What is narcolepsy, and how can it affect your life and sleep health? Read on to find a comprehensive narcolepsy definition from expert medical sources, as well as a list of narcolepsy facts and information.

Here at the ResMed blog, we generally focus on sleep apnea. However, the best way to fully understand sleep apnea is to educate ourselves about sleep health in general. With that in mind, we’re exploring sleep disorders other than sleep apnea, such as insomnia, restless legs syndrome and narcolepsy.

What is narcolepsy? Narcolepsy definitions from the experts

So, what is narcolepsy, exactly? Defining narcolepsy as a health condition that causes “daytime sleep attacks,” the National Heart, Lung and Blood Institute (NHLBI) also states that this sleep disorder can cause “periods of extreme daytime sleepiness” and “muscle weakness.”1

The National Institute of Neurological Disorders and Stroke (NINDS) calls narcolepsy “a chronic brain disorder” that affects “control of sleep-wake cycles.”2 Although the exact cause isn’t known, recent studies have tended to attribute it to a disorder of the REM sleep cycle.2,3 (REM is “rapid-eye movement” sleep, which experts believe makes up about 20 percent of an average adult’s sleep cycle.)4

At this point, narcolepsy definitions generally move into symptoms and effects of the condition. “People with narcolepsy often find it difficult to stay awake for long periods of time,” states the Mayo Clinic website in its narcolepsy definition. “Narcolepsy can cause serious disruptions in your daily routine.”5

In its definition of narcolepsy, the NHLBI states that some people with narcolepsy “fall asleep suddenly, even if they’re in the middle of talking, eating, or another activity,”1 and the NINDS states that people “experience periods of extreme daytime sleepiness and sudden, irresistible bouts of sleep that can strike at any time” and typically last “a few seconds to several minutes.”2

We’ll explore narcolepsy symptoms in more detail next week. For now, let’s break down some basic narcolepsy facts and explore what it means to be faced with this rare but serious sleep disorder.

Narcolepsy facts, from the experts

People diagnosed with narcolepsy are referred to as “narcoleptics.” Other basic narcolepsy facts include:

Narcoleptics aren’t constantly asleep. Contrary to conventional thought, narcoleptics don’t spend “a substantially greater proportion of their time asleep during a 24-hour period than do normal sleepers,” according to the NINDS.2

Narcolepsy isn’t caused by depression. Nor is it related to “seizure disorders, fainting, simple lack of sleep or other conditions that may cause abnormal sleep patterns,” according to the Mayo Clinic.5 In fact, according to the U.S. Department of Health and Human Services’ narcolepsy fact sheet, narcolepsy has “no known cause” (more on this next week).6

Narcolepsy can affect your lifestyle in dangerous ways. Narcolepsy can affect your lifestyle in serious, even dangerous ways. “People may unwillingly fall asleep while at work or at school, when having a conversation, playing a game, eating a meal, or, most dangerously, when driving or operating other types of machinery,” states the NINDS overview of narcolepsy.2

Narcolepsy can happen to anyone. Unlike insomnia, narcolepsy seems to occur just as frequently in males as it does in females, and is found throughout the world. “Symptoms often start in childhood or adolescence, but can occur later in life,” the NINDS adds, pointing out that “about one in every 3,000 Americans” has it.2

We have also explored the symptoms and causes of narcolepsy, as well as potential treatment options.



  1. National Heart, Lung, and Blood Institute (NHLBI). “What Is Narcolepsy?” Published/updated Nov. 1, 2010. Retrieved from https://www.nhlbi.nih.gov/health/health-topics/topics/nar/ (accessed May 2, 2014).
  2. National Institute of Neurological Disorders and Stroke (NINDS). “Narcolepsy Fact Sheet.” NIH Publication 13-1637. Published/updated Apr. 16, 2014. Retrieved from http://www.ninds.nih.gov/disorders/narcolepsy/detail_narcolepsy.htm (accessed May 2, 2014).
  3. Nishino S, et al. “Is narcolepsy a REM sleep disorder? Analysis of sleep abnormalities in narcoleptic Dobermans.” Neurosci Res. 2000 Dec;38(4):437-46. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11164570 (accessed May 2, 2014).
  4. NINDS. “Brain Basics: Understanding Sleep.” NIH Publication 06-3440-c. Published/updated April 28, 2014. Retrieved from http://www.ninds.nih.gov/disorders/brain_basics/understanding_sleep.htm (accessed May 2, 2014).
  5. Mayo Clinic Staff. “Narcolepsy: Definition.” Published Oct. 20, 2012 on the Mayo Clinic website. Retrieved from http://www.mayoclinic.org/diseases-conditions/narcolepsy/basics/definition/con-20027429 (accessed May 2, 2014).
  6. U.S. Department of Health and Human Services. “Facts about Narcolepsy.” NIH Publication 96-3649. Published Oct. 1996.

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