What is the Test for Narcolepsy?

Do you know that it is a serious medical condition? Narcolepsy affects an estimated 1 in 3,000 Americans. And living with the disease is very challenging.

You may have heard of narcolepsy before or recall a movie character hysterically falling asleep while walking. Our favorite TV dad, Homer Simpson, was diagnosed with narcolepsy in the premiere episode of the 27th season of The Simpsons after sleeping through a workplace fire that badly burned him. Homer used his doctor’s note to get out of doing household chores, driving Marge to file for legal separation. The episode is hilarious, but also highlights some of the real-life consequences of this sleep disorder.

We’ll look into the causes, diagnosis and treatment for this sleep disorder.

What is narcolepsy?

Narcolepsy is a sleep disorder affecting an estimated 1 in 3,000 Americans; however, with increased education about the disease, the prevalence is expected to increase. It is a neurological disorder caused by the brain’s inability to regulate the sleep-wake cycle. 

Our time asleep is divided into two main types of sleep

NREM (non-rapid-eye-movement) 

There are 3 stages of NREM sleep that make up 75% of our sleeping time. As we progress through these stages, our brain function decreases. 

Stage 1: Light, transitionary phase between sleeping and wakefulness. 

Stage 2: When you begin to drop into deeper sleep.

Stage 3: The deepest sleep stage. It is called slow-wave sleep because your brain activity moves up and down in synchronized waves. It is hard to wake someone from this type of sleep. 

REM (rapid-eye-movement) 

The brain is more active during REM sleep than NREM sleep; it can even rival our waking brain activity. Dreams occur during this sleep stage, your heart rate increases, your muscles become paralyzed, and your eyes twitch in various directions (hence the name).

For people with narcolepsy, sleep begins almost immediately with REM sleep and fragments of REM occur involuntarily throughout the waking hours.  Due to the sudden transition into REM sleep, narcolepsy patients may experience paralysis and hallucinations while still awake (read more about that in the symptoms section below).

Despite the perception that people with narcolepsy are perpetually sleepy, they do not typically sleep more than the average person. Narcolepsy is considered a “state boundary” control abnormality. Narcolepsy patients sleep a normal amount but cannot control the timing of sleep.

There are two types of narcolepsy:

Type 1: Narcolepsy with cataplexy (we’ll explain cataplexy below).

Type 2: Narcolepsy without cataplexy.

What are the symptoms of narcolepsy?

  1. Excessive daytime sleepinessThe most common symptom of narcolepsy is EDS, Excessive Daytime Sleepiness, which is closely related to fatigue. EDS is a sensation of persistent drowsiness, even after a full night’s sleep,  that results in impaired concentration and lack of energy. It can be punctuated by periods of “microsleep”, in which individuals may drift off for a short time without realizing it, and maybe without even interrupting their current task, such as driving or typing or other inappropriate times (see Francis inappropriately sleeping at his work space in the picture above).
  2. Cataplexy: sudden loss of muscle tone, usually triggered by emotional stimuli such as laughter, surprise, or anger. It may involve all muscles and result in collapse. It may only affect certain muscle groups and result in slurred speech, buckling of the knees, or weakness in the arms. Consciousness is maintained throughout the episode but the patient is usually unable to speak.
  3. Hypnagogic hallucinations: during transition from wakefulness to sleep, the patient has bizarre, often frightening dream-like experiences that incorporate his or her real environment.
  4. Sleep paralysisa temporary inability to move during sleep-wake transitions. Sleep paralysis may last for a few seconds to several minutes and may accompany hypnagogic hallucinations.
  5. Fragmented nighttime sleep: waking up repeatedly through the night. 

Who gets narcolepsy?

About 0.02% of African American, Caucasian, and Japanese individuals have narcolepsy. It is typically discovered in the the second and third decades of life (10-20s) and affects males and females equally. There may be combination of genetic or environmental factors that cause the disease. 

How is narcolepsy diagnosed?

Like other sleep disorders, narcolepsy patients may suffer with the disease for years before being properly diagnosed. 

  1. Sleep history and records: Your doctor will ask you for a detailed sleep history. A part of the history involves filling out the Epworth Sleepiness Scale, which uses a series of short questions to gauge your degree of sleepiness. You may be asked to keep a detailed diary of your sleep pattern for one to two weeks, so your doctor can compare how your sleep pattern and alertness are related.
  2. Sleep study: The most common test for narcolepsy is an overnight polysomnogram (PSG, click here for more info on this test) followed by a daytime multiple sleep latency test (MSLT).IMPORTANT: Because the patient’s symptoms, like excessive daytime sleepiness, could be caused by another sleep disorder, such as sleep apnea, it is very important that the patient has an overnight sleep study the night before the daytime study. The overnight study will assess the quality of the night time sleep and may rule out other sleep disorders. If there is evidence of another sleep disorder during the overnight portion, the daytime MSLT may be canceled. Both tests may be repeated at a later date once the other sleep disorder is treated or ruled out as a cause of the EDS.
  3. Blood test: A less common test looks at a genetic marker called the Narcolepsy-Associated Antigen, that is found in 90% to 95% of African American, Caucasian, and Japanese patients with narcolepsy who also have cataplexy (narcolepsy type 1), but only in 45% to 50% of patients with narcolepsy without cataplexy (narcolepsy type 2). Because about 25% of normal people have this gene, the absence of this gene is considered good evidence that the patient with cataplexy does NOT have narcolepsy; however, it’s absence doesn’t rule out narcolepsy without cataplexy (narcolepsy type 2).

How is narcolepsy treated?

Like sleep apnea, narcolepsy can be treated, but not cured. 

Medications for narcolepsy include:

  • Stimulants: Drugs that stimulate the central nervous system to keep you awake during the day so that you can sleep at night.
  • SSRIs or SNRIs: These drugs suppress REM sleep and reduce symptoms of cataplexy, hypnagogic hallucinations and sleep paralysis. 
  • Tricyclic antidepressants: These older antidepressants are effective for cataplexy.
  • Sodium oxybate (Xyrem): This medication is highly effective for cataplexy and improves nighttime sleep and may control daytime sleepiness. It has a short half-life and must be taken in two doses- one at bedtime and one four hours later. It is a highly controlled medication.

Lifestyle changes can also alleviate symptoms. Your doctor may recommend following a strict sleep timetable, which may include scheduled naps during the day, seeking counseling, and avoiding caffeine, alcohol, and large meals.

For more information on medications used to treat narcolepsy, visit the Mayo Clinic website here.

Has your doctor referred you for a test to rule out narcolepsy? Are you suffering from excessive daytime sleepiness and need a sleep study?

Request a sleep study


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  1. Sheila Weir Reply

    What are the best drugs for narcolepsy without cateplexy?

  2. Julia Rodriguez Reply

    Hi, Shiela. Stimulants may be prescribed for the excessive daytime sleepiness from narcolepsy. The Narcolepsy Network has lots of great resources, including lists of common medications to control sleepiness and and REM sleep intrusion http://narcolepsynetwork.org/about-narcolepsy/treatment/narcolepsy-medications/

  3. Feri Ascencion Reply

    1st question.
    Most scientists refer to narcolepsy as it affecting an estimated 1 in 2,000 Americans. Since when did this number change or what is the reason it is mentioned in this article as 1 in 3,000?
    2nd question.
    I might understand this wrong but does this article imply Latinos and Native Americans don’t get narcolepsy?

  4. Feri Ascencion Reply

    No I haven’t yet Julia.
    What I do know, but would need to find the study again, is the enormous difference with Japan where each 1 out of 600 is supposed to have narcolepsy. I’ve always wondered what could cause such a big difference compared to the world wide numbers and if it is an indication that narcolepsy is more genetic than presumed up to now. In that theory we would be talking about the closed Japanese community and habits where tradition is still an important aspect and almost demands every Japanes to marry another Japanese. Anyway…just theory.
    I see how you got to the 1 out of 3000 number.
    I’m aware we, the narcolepsy advocates and non profit organizations rather use the “worst” numbers. It will still be an estimated only and very hard to determine where the numbers are when we consider approximately 70 to 75% of the patients not being diagnosed.
    Unfortunately I don’t expect that many changes in these numbers as long as Medical School doesn’t spend more time on sleeping distortions in general. I might have some very interesting material and documents to share with you. Feel free to send me a direct email so I’ll know where to send them.

  5. Feri Ascencion Reply

    For all people with narcolepsy who haven’t found us yet. Come to Facebook groups. We are sharing not only experiences but valuable information too there. You’l love it!
    More on all these groups at http://pwn4pwn.org/n-on-facebook/

  6. Diana Reply

    Thanks Feri and Julia. 🙂 Nice to see links to Narcolepsy Network and support groups on Facebook. Both very valuable to patients, families and friends.

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