What Is Narcolepsy?

Reviewed by: HU Medical Review Board | Last reviewed: June 2020

Narcolepsy is a sleep disorder in which someone falls asleep without meaning to, often several times a day. This may occur in the middle of an activity, such as driving, eating, working, or talking. Some people with narcolepsy go limp or lose muscle tone following a strong emotion such as laughter. This is called cataplexy.

Narcolepsy is a life-long problem. Between 135,000 and 200,000 people in the U.S. have narcolepsy. However, since many people are undiagnosed or misdiagnosed, these numbers may be much higher. Narcolepsy is often incorrectly treated as a mental health or seizure disorder for years before a correct diagnosis is made.1

Types of narcolepsy

There are 2 main types of narcolepsy:1

Type 1 narcolepsy, which used to be called narcolepsy with cataplexy. Most people with type 1 narcolepsy have low levels of the brain hormone hypocretin. Cataplexy is usually triggered by strong emotions such as surprise, fear, or laughter.

Type 2 narcolepsy, which used to be called narcolepsy without cataplexy. Most people with this type of narcolepsy have normal levels of hypocretin.

Narcolepsy may also be caused by other health conditions that affect hypocretin levels in the brain. This is called secondary narcolepsy. Conditions that may cause narcolepsy include:

  • Brain injury
  • Autoimmune disorders
  • Brain tumor
  • Encephalitis
  • Parkinson’s disease

What causes narcolepsy?

Doctors believe that most narcolepsy is caused by a combination of genetics and the environment. Most people with narcolepsy have no known family history. It affects males and females equally.1

People who have narcolepsy with cataplexy almost always show low levels of the brain hormone hypocretin, while hypocretin is normal in people without cataplexy. Only 10 percent of those who have narcolepsy with cataplexy have a close relative with the condition.1

Autoimmune disorders and brain injuries also may cause narcolepsy.1

Symptoms of narcolepsy

The most common symptoms of narcolepsy are excessive daytime sleepiness, cataplexy, sleep paralysis, and hallucinations. Sometimes symptoms improve over time but rarely disappear completely. Cataplexy occurs in almost no other diseases.1

Other symptoms include insomnia, fragmented sleep, and automatic behaviors. Automatic behavior means the person continues a complex task such as driving while asleep. They often can’t remember what they did when they wake up.1

Symptoms usually begin between the ages of 7 and 25.1

How is narcolepsy diagnosed?

A physical exam, medical history, and several tests are used to diagnose narcolepsy. First, your doctor will look at your overall health and sleep habits. This may help rule out any other conditions that may cause similar symptoms. You may be asked to keep a sleep journal for 1 to 2 weeks to record the times you fall asleep and for how long.

Two tests will be done in a sleep disorders clinic to diagnose narcolepsy:1

  • Polysomnography (PSG or sleep study): An overnight test in a sleep lab that records brain and muscle activity, breathing, and eye movements.
  • Multiple sleep latency test (MSLT): Measures how quickly someone falls asleep and when and if they enter REM sleep. Going into REM sleep within 15 minutes on two naps is consistent with narcolepsy.

Sometimes a spinal tap may be needed to measure the level of hypocretin in the brain and spinal fluid. Hypocretin is a brain hormone that helps control sleep. People with low levels of this hormone often have type 1 narcolepsy or narcolepsy with cataplexy.1

Two self-tests can give you an idea of whether you should talk with your doctor about daytime sleepiness:2-3

Treatments for narcolepsy

Narcolepsy cannot be cured but it can be controlled with medicine. Several drugs can help improve the symptoms of narcolepsy, including:1,4

  • Stimulants such as modafinil (Provigil), amphetamines (Adderall), or methylphenidate (Ritalin)
  • Certain antidepressants
  • Sodium oxybate (also known as gamma hydroxybutyrate or GHB)
  • Pilotisant (Wakix)
  • Solriamfetol (Sunosi)
  • Short, day-time naps

People being treated for narcolepsy should see their doctor at least every 6 months. It is important to watch for drug side effects, changes in sleep or mood, and other health issues.4

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