Massachusetts General Hospital

Narcolepsy

What is narcolepsy?

Narcolepsy is a chronic, neurological sleep disorder with no known cause. It involves the body's central nervous system. Narcolepsy is a genetic disorder, and is caused by a deficiency in the production of a neuropeptide called orexin by a part of the brain called the hypothalamus.

The main characteristic of narcolepsy is excessive and overwhelming daytime sleepiness, even after adequate nighttime sleep. A person with narcolepsy is likely to become drowsy or to fall asleep at inappropriate times and places, and sleep attacks may occur with or without warning.

Attacks can occur repeatedly in a single day, drowsiness may persist for prolonged periods of time, and nighttime sleep may be fragmented with frequent awakenings.

What are the symptoms of narcolepsy?

The following are the most common symptoms of narcolepsy. However, individuals may experience symptoms differently. Symptoms may include:

• Excessive daytime sleepiness (EDS). An overwhelming desire to sleep at inappropriate times.

• Cataplexy. A sudden loss of muscle control ranging from slight weakness to total collapse.

• Sleep paralysis. Being unable to talk or move for about one minute when falling asleep or waking up.

• Hypnagogic hallucinations. Vivid and often scary dreams and sounds reported when falling asleep.

Secondary or auxiliary symptoms include:

• Automatic behavior. Performing routine tasks without conscious awareness of doing so, and often without memory of it.

• Disrupted nighttime sleep, including multiple arousals

• Other difficulties may result from one's continuing struggle to cope, including:

  • Feelings of intense fatigue and continual lack of energy

  • Depression

  • Difficulty in concentrating and memorizing

  • Vision (focusing) problems

  • Eating binges

  • Weak limbs

  • Difficulties in handling alcohol

How is narcolepsy diagnosed?

A combination of EDS and cataplexy provide for preliminary clinical diagnosis.

In addition to a complete medical history and physical examination, laboratory tests to confirm diagnosis and plan treatment may include:

• Overnight polysomnogram (PSG). A sleep test to monitor various parameters during an entire night of sleep. 

• Multiple Sleep Latency Test (MSLT). Measures sleep onset and how quickly rapid eye movement (REM) sleep occurs.

• Genetic blood test. To test for a genetic mutation often found in people who have a predisposition to narcolepsy.

How is narcolepsy treated?

Specific treatment will be determined by your doctor based on:

• Your age, overall health, and medical history

• Severity of the disease

• Your tolerance for specific medications, procedures, or therapies

• Expectations for the course of the disease

• Your opinion or preference

The goal of treatment of narcolepsy is for the patient to remain as alert as possible during the day and to minimize any recurring episodes of cataplexy, while using a minimal amount of medication.

• Medications. Excessive daytime sleepiness and cataplexy are treated separately, with central nervous system stimulants usually prescribed for EDS and antidepressants for cataplexy.

• Nap therapy. Two or three short naps during the day may help control sleepiness and maintain alertness.

• Proper diet

• Regular exercise

• Behavioral therapy