Narcolepsy

What Is Narcolepsy? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Katherine Lee
By Medically Reviewed by 
Reviewed:
Medically Reviewed

Narcolepsy is a chronic neurological condition in which the brain’s ability to regulate sleep-wake cycles is impaired. Individuals with this sleep disorder frequently experience trouble sleeping at night and periods of intense sleepiness during the day because the various stages of sleep happen at the wrong times.

People with narcolepsy may experience “sleep attacks” — an overwhelming need to sleep during the day that comes on quickly. While awake and fully conscious, people with narcolepsy may also experience what’s called cataplexy, in which their muscles abruptly and without warning go limp — in some cases right in the middle of an activity like laughing, eating, or talking.

It’s important to see your doctor if you think you or a loved one may have narcolepsy. It can interfere with school, work, and relationships and can lead to depression, anxiety, learning difficulties, and even accidents and injuries. While knowledge about symptoms, diagnosis, and treatment have improved, it can take years to get a correct diagnosis, exacting a significant toll on an individual’s quality of life. Here’s a primer on what it means to have narcolepsy, what causes the disorder, symptoms you might experience, treatments, and how to live with it.

The Two Types of Narcolepsy

Doctors categorize narcolepsy in two ways.

Type 1 typically involves cataplexy, the sudden loss of voluntary muscle control brought on by strong feelings such as anger, fear, excitement, stress, or even laughter. People with type 1 narcolepsy have unusually low levels of the brain chemical hypocretin, which plays a key role in preventing rapid eye movement (REM) sleep from occurring at the wrong time. REM sleep follows the deepest stage of sleep; it’s when dreaming and key processes involved in making memories occur.

In the past, type 1 was called narcolepsy with cataplexy.

RELATED: What Makes Someone a Light or Heavy Sleeper?

Type 2 narcolepsy is characterized by milder symptoms, normal levels of the brain chemical hypocretin, and no cataplexy.

Some people may start out with type 2 narcolepsy and later develop cataplexy, says Eric Olson, MD, a professor of medicine and sleep medicine specialist at the Mayo Clinic in Rochester, Minnesota. This type was previously called narcolepsy without cataplexy.

Signs and Symptoms of Narcolepsy

Because people with narcolepsy have impaired sleep cycles, the most common problem is not being able to sleep soundly and consistently throughout the night. As a result, the one symptom that everyone with narcolepsy shares is excessive daytime sleepiness.

More specifically, in people with narcolepsy, REM (rapid eye movement) sleep occurs at the wrong time. This is the stage of sleep in which dreaming occurs and our bodies naturally become immobilized so that we don’t harm ourselves by thrashing about while we sleep. In people with narcolepsy, REM happens soon after they fall asleep. (REM sleep normally occurs much later, about 90 minutes after a person falls asleep.)

The lines between dreaming and waking can become blurred, resulting in vivid dreams and paralysis as a person wakes up. The following are some of the symptoms that someone with narcolepsy may experience:

  • Excessive Daytime Sleepiness People with narcolepsy may feel refreshed when they wake up in the morning, only to feel extremely tired as the day goes on. This can cause an overwhelming urge to fall asleep, even at a meal, at work, or with friends or family.

    These sleep attacks are different from cataplexy, the most dramatic symptom of narcolepsy.
  • Cataplexy This sudden loss of muscle tone and control occurs when someone with narcolepsy experiences a strong emotion, such as joy, surprise, fear, or anger. Cataplexy can range from mild (such as a barely noticeable feeling of slight drooping in the eyelids) to severe (the entire body collapsing). People are awake during these episodes, but they may not be able to move or talk. Some people may experience an episode of cataplexy just once or twice in a lifetime, while others may have several in one day. Episodes last no more than a few minutes and resolve on their own.

  • Fragmented Sleep A disturbed sleep cycle often means a short and frustrating night’s sleep for people with narcolepsy. Insomnia, restless leg syndrome, and sleep apnea may occur, breaking up sleep.

  • Sleep Paralysis Our muscles are temporarily paralyzed during REM sleep (thought to be an evolutionary safety mechanism that prevents us from acting out our dreams), but in people with narcolepsy, it can happen at the wrong time. This symptom can leave these individuals awake and unable to move. The paralysis typically lasts only a few seconds or minutes.
  • Hallucinations These are vivid, dreamlike visions that take on an extra-real quality. They are called “hypnagogic” if they happen while someone is falling asleep and “hypnopompic” if they occur while they are waking up.
Any of these symptoms can be inconvenient, dangerous (in the case of severe cataplexy), bewildering, scary, or uncomfortable.

RELATED: Why Our Bodies Need Sleep

Because the symptoms of narcolepsy — such as excessive daytime sleepiness, cataplexy, hallucinations when waking up, and sleep paralysis — often resemble those of other health conditions, such as an illness or a psychiatric disorder, misdiagnosis of narcolepsy is common.

Learn More About the Signs and Symptoms of Narcolepsy

Causes and Risk Factors of Narcolepsy

It wasn’t until the early 2000s that research revealed that people with type 1 narcolepsy have abnormally low levels of hypocretin, a chemical in the brain that helps regulate sleep and wakefulness.

Doctors don’t yet know exactly what causes the hypocretin loss, but they suspect it may have something to do with the immune system mistakenly attacking these brain cells, which help regulate the sleep-wake cycle and prevent REM sleep from happening at the wrong time, explains Emmanuel Mignot, MD, a professor of sleep medicine at Stanford University in California. Dr. Mignot led initial research that linked hypocretin loss to narcolepsy, and that has led to the discovery of promising treatments that target hypocretin receptors on cells in the brain.

In type 1 narcolepsy, nearly all the brain cells that contain hypocretin are destroyed. The cause of type 2 remains unknown, but it may involve the loss of some of the cells that produce and contain hypocretin or changes in cell receptors involved in sending and receiving hypocretin signals.

This means that people are not born with narcolepsy, but rather they may or may not have the genetic predisposition to develop the condition, Mignot says. In some people with this genetic predisposition, it’s thought that something goes awry when the immune system goes into action to fight off the flu or other infection and in error attacks the hypocretin neurons.

Most of the time, people with narcolepsy have no family history of the disorder. But about 1 in 10 people with type 1 narcolepsy have one or more close relatives with it. In rare instances, a brain injury can also trigger narcolepsy symptoms.

The Definition of Narcolepsy and What Causes It

How Is Narcolepsy Diagnosed?

To determine whether someone has narcolepsy, doctors typically conduct a physical exam and take a complete medical and family history. That information will be evaluated along with the results of two types of sleep tests, which are conducted in a sleep lab:

Polysomnogram (PSG) This test is an overnight sleep study that tracks brain activity during slumber, as well as muscle activity, breathing, and eye movement. A PSG pinpoints periods of REM sleep and can help tell your doctor whether it’s happening at the wrong time, a sign of narcolepsy.

Multiple Sleep Latency Test (MSLT) This test may be conducted the day after a PSG if you’ve gotten at least six hours of sleep during the PSG and had no signs of other sleep disorders. For the MSLT, you take up to four or five 20-minute naps, spaced about two hours apart, in a sleep lab, and your brain activity and sleep duration are checked. Falling into rapid-onset REM sleep and taking short naps can be signs of narcolepsy.

Specialists may also test levels of hypocretin-1 in cerebrospinal fluid. Low levels can help confirm a diagnosis of type 1 narcolepsy.

Doctors suspect that narcolepsy is underdiagnosed because it is often mistaken for other conditions with similar symptoms such as depression, obstructive sleep apnea, or insomnia. One study found that as many as 60 percent of people with narcolepsy were misdiagnosed.

Learn More About Diagnosing Narcolepsy

Prognosis of Narcolepsy

There’s no cure for narcolepsy, but with treatment, people can expect to regain about 80 percent of normal functioning — in terms of restful sleep at night, alertness, and the ability to function during the day.

Treatment is especially effective at relieving excessive daytime sleepiness and cataplexy.

You may find that symptoms worsen over the first 20 to 30 years after narcolepsy first appears, then ease somewhat after that.

Duration of Narcolepsy

Narcolepsy is a lifelong condition, but symptoms don’t tend to worsen as a person ages and may even improve over time.

A combination of medications and lifestyle adjustments can be quite effective in helping patients manage their narcolepsy symptoms.

Treatment and Medication Options for Narcolepsy

Medications such as modafinil (Provigil), pitolisant (Wakix), and stimulant drugs, including the ADHD drugs dextroamphetamine (Dexedrine) and methylphenidate (Ritalin), have been shown to be effective in treating daytime sleepiness.

Antidepressants such as fluoxetine (Prozac) and venlafaxine (Effexor), as well as sodium oxybate (Xyrem), have proven helpful in reducing cataplexy.

And sodium oxybate can also ease sleep-related disturbances, paralysis, and hallucinations.

Lifestyle and behavior changes doctors may recommend include incorporating healthy sleep habits, such as sleeping at least seven hours per night, and keeping a regular schedule (going to bed and waking up around the same time each day).

Your doctor may also suggest you take strategic naps throughout the day to reduce daytime sleepiness and improve energy, exercise regularly, and avoid caffeine and alcohol close to bedtime. It’s also wise to avoid medications that can make you feel sleepy, such as narcotics and allergy medications.

Staying safe while you drive is crucial. Depending on your symptoms, your doctor may advise you to avoid night driving and long drives or to take naps before you set out or during breaks scheduled throughout your trip. Your doctor may recommend that you take a test of how well you stay awake over extended periods of time to help evaluate how well your medications are working and whether you should limit driving.

Learn More About Treatment and Medication Options for Narcolepsy

How Narcolepsy Affects Learning

Narcolepsy doesn’t affect intelligence, but it can affect someone’s ability to learn because of excessive drowsiness during the day, sleep attacks, sudden loss of muscle control, or the need to take breaks.

Diagnosis and treatment is important for students with narcolepsy, as is clear communication between the student, parents, teachers, and school administrators. It’s also important to know that students with narcolepsy may be legally eligible for specialized education plans that provide accommodations so they can learn in an environment that meets their needs. These adjustments may include help with note-taking, extra time for tests, a flexible schedule, and nap time.

Learn More About Navigating School and Learning With Narcolepsy

Prevention of Narcolepsy

While there’s no way to prevent narcolepsy, promising research may lead to methods that allow scientists to replace the missing brain chemical hypocretin, according to Mignot. Researchers are looking for ways to stop the destruction of hypocretin before it happens, in order to prevent narcolepsy in people who are at risk for developing the disease.

Complications of Narcolepsy

People with narcolepsy may be at higher risk for depression and anxiety. Researchers don’t know, however, whether mood disorders are linked directly to the brain changes at the root of this disorder or if they develop because of narcolepsy’s effects on people’s daily lives.

Research and Statistics: Who Has Narcolepsy?

Narcolepsy affects about 1 in 2,000 people.

It’s estimated that up to 200,000 people in the United States have narcolepsy, though the actual number may be higher due to underdiagnosis.

Narcolepsy is the second most common reason for daytime sleepiness diagnosed at U.S. sleep centers.

Narcolepsy may develop at any time in life, but it most often starts in childhood through young adulthood. Symptoms are often noticed in kids, teens, and young adults (from age 7 to 25) — with more than 50 percent of patients reporting their narcolepsy symptoms before age 18. But a person can develop narcolepsy later in life, too.

One unknown about this condition: One in four Americans carry a genetic marker for it, but just 1 in 500 of these people will develop narcolepsy.

Current narcolepsy research focuses on causes, symptoms, and treatments for adults and children with narcolepsy. These subject areas include:

Genetics Researchers are looking at a variety of genes that may be involved in the development of narcolepsy, such as genes that regulate human leukocyte antigen (HLA), which helps the immune system distinguish between “friendly” proteins made by your own body and “unfriendly” proteins from outside invaders. Many people with narcolepsy have a variation in an HLA-related gene that may interfere with this process.

Targeting Hypocretin Abnormalities In early lab studies, researchers are looking at ways to stimulate the brain’s hypocretin receptors to make up for low levels in narcolepsy.

Others are looking at ways to encourage other cells in the human brain to manufacture hypocretin, possibly using stem cell techniques or other approaches.

Boosting Histamine Signals Experimental therapies could increase alertness by keeping more of the brain chemical histamine active in the brain.

Related Conditions of Narcolepsy

People with narcolepsy may be at higher risk for obesity, diabetes, chronic pain, and chronic obstructive pulmonary disease.

The reason for the association was unknown but could be related to poor sleep or to low levels of hypocretin, which they note also helps regulate eating and activity levels.

Resources We Love

American Academy of Sleep Medicine

In addition to extensive information aimed at healthcare practitioners, this website from the organization that accredits sleep centers and medical sleep practices also has a ton of information for patients. Consumers can find recent updates about narcolepsy — including FDA-approvals of new drugs — and patient guides to common sleep problems that may affect people with narcolepsy.

Sleep Foundation

The go-to destination for consumer health information about all things sleep-related, this website features articles reviewed by a team of well-credentialed sleep specialists. A section on narcolepsy goes beyond the basics, covering the disorder’s effects on work, school, relationships, and more.

Project Sleep

This nonprofit is dedicated to raising awareness about sleep health. Check out their smart, compelling videos about real people with narcolepsy — including this one about nurses living with the condition. You’ll find practical information about supporting good sleep, plus ways to get involved as an advocate for narcolepsy awareness through Project Sleep’s Rising Voices project.

Wake Up Narcolepsy

A national leader in narcolepsy research and awareness, Wake Up Narcolepsy raises funds for cutting-edge scientific research into this disorder. The website includes a podcast featuring interviews with real people who have narcolepsy.

Julie Flygare’s Wide Awake and Dreaming: One Step Ahead of Narcolepsy

This is a compelling personal blog from the founder of Project Sleep. Flygare is an attorney and serious runner (she has run the Boston Marathon), and in 2009 she collaborated with Harvard Medical School on a narcolepsy awareness educational program for medical students based on her own experiences. She writes honestly about living and working with narcolepsy. Athletes will appreciate her posts specifically about running.

Additional reporting by Sari Harrar.

Editorial Sources and Fact-Checking

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