What is narcolepsy?
Narcolepsy is a chronic sleep disorder with no known cause. The
main characteristic of narcolepsy is
overwhelming daytime sleepiness
, even after adequate
nighttime sleep. A person with narcolepsy is likely to become
drowsy or to fall asleep, often at inappropriate times and places.
Daytime sleep attacks may occur with or without warning and may be
irresistible. These attacks can occur repeatedly in a single day.
Drowsiness may persist for prolonged periods of time. In addition,
nighttime sleep may be fragmented with frequent wakenings. Three
other classic symptoms of narcolepsy, which may not occur in all
sudden episodes of loss of muscle function,
ranging from slight weakness (such as limpness at the neck or
knees, sagging facial muscles, or inability to speak clearly) to
complete body collapse. Attacks may be triggered by sudden
emotional reactions such as laughter, anger, or fear and may last
from a few seconds to several minutes. The person remains conscious
throughout the episode.
- Sleep paralysis:
temporary inability to talk or move
when falling asleep or waking up. It may last a few seconds to
- Hypnagogic hallucinations:
vivid, often frightening,
dream-like experiences that occur while dozing or falling
Daytime sleepiness, sleep paralysis, and hypnagogic
hallucinations can also occur in people who do not have
. In most cases, the first symptom of narcolepsy to
appear is excessive and overwhelming daytime sleepiness. The other
symptoms may begin alone or in combination months or years after
the onset of the daytime sleep attacks. There are wide variations
in the development, severity, and order of appearance of cataplexy,
sleep paralysis, and hypnagogic hallucinations in individuals. Only
about 20 to 25 percent of people with narcolepsy experience all
four symptoms. The excessive daytime sleepiness generally persists
throughout life, but sleep paralysis and hypnagogic hallucinations
may not. The symptoms of narcolepsy, especially the excessive
daytime sleepiness and cataplexy, often become severe enough to
cause serious disruptions in a person's social, personal, and
professional lives and severely limit activities.
When should you suspect it?
You should be checked for narcolepsy if:
- you often feel excessively and overwhelmingly sleepy during the
day, even after having had a full night's sleep
- you fall asleep when you do not intend to, such as while having
dinner, talking, driving, or working
- you collapse suddenly or your neck muscles feel too weak to
hold up your head when you laugh or become angry, surprised, or
- you find yourself briefly unable to talk or move while falling
asleep or waking up
How common is it?
Although it is estimated that narcolepsy afflicts as many as
200,000 Americans, fewer than 50,000 are diagnosed. It is as
widespread as Parkinson's disease or multiple sclerosis and more
prevalent than cystic fibrosis, but it is less well known.
Narcolepsy is often mistaken for depression, epilepsy, or the side
effects of medications.
Who gets it?
Narcolepsy can occur in both men and women at any age, although
its symptoms are usually first noticed in teenagers or young
adults. There is strong evidence that narcolepsy may run in
families. 8 to 12 percent of people with narcolepsy have a close
relative with the disease.
What happens in narcolepsy?
Normally, when an individual is awake, brain waves show a
regular rhythm. When a person first falls asleep, the brain waves
become slower and less regular. This sleep state is called
non-rapid eye movement (NREM) sleep.
After about an hour and
a half of NREM sleep, the brain waves begin to show a more active
pattern again, even though the person is in deep sleep. This sleep
state, called rapid eye movement (REM) sleep, is when dreaming
occurs. In narcolepsy, the order and length of NREM and REM sleep
periods are disturbed, with REM sleep occurring at sleep onset
instead of after a period of NREM sleep. Thus, narcolepsy is a
disorder in which REM sleep appears at an abnormal time. Also, some
of the aspects of REM sleep that normally occur only during
sleep--lack of muscle tone, sleep paralysis, and vivid
dreams--occur at other times in people with narcolepsy. For
example, the lack of muscle tone can occur during wakefulness in a
cataplexy episode. Sleep paralysis and vivid dreams can occur while
falling asleep or waking up.
How is it diagnosed?
Diagnosis is relatively easy when all the symptoms of narcolepsy
are present. But if the sleep attacks are isolated and cataplexy is
mild or absent, diagnosis is more difficult. Two tests that are
commonly used in diagnosing narcolepsy are the
multiple sleep latency test
. These tests are usually
performed by a sleep specialist. The polysomnogram involves
continuous recording of sleep brain waves and a number of nerve and
muscle functions during nighttime sleep. When tested, people with
narcolepsy fall asleep rapidly, enter REM sleep early, and may
awaken often during the night. The polysomnogram also helps to
detect other possible sleep disorders that could cause daytime
sleepiness. For the multiple sleep latency test, a person is given
a chance to sleep every 2 hours during normal wake times.
Observations are made of the time taken to reach various stages of
sleep. This test measures the degree of daytime sleepiness and also
detects how soon REM sleep begins. Again, people with narcolepsy
fall asleep rapidly and enter REM sleep early.
How is it treated?
Although there is no cure for narcolepsy, treatment options are
available to help reduce the various symptoms. Treatment is
individualized depending on the severity of the symptoms, and it
may take weeks or months for an optimal regimen to be worked out.
Complete control of sleepiness and cataplexy is rarely possible.
Treatment is primarily by
are also important. The main treatment of excessive
daytime sleepiness in narcolepsy is with a group of drugs called
central nervous system stimulants
. For cataplexy and other
REM-sleep symptoms, antidepressant medications and other drugs that
suppress REM sleep are prescribed. Caffeine and over-the-counter
drugs have not been shown to be effective and are not recommended.
In addition to drug therapy, an important part of treatment is
(10 to 15 minutes) two to three times
per day to help control excessive daytime sleepiness and help the
person stay as alert as possible. Daytime naps are not a
replacement for nighttime sleep. Ongoing communication among the
physician, the person with narcolepsy, and family members about the
response to treatment is necessary to achieve and maintain the best
How can individuals and their families and friends
cope with narcolepsy?
Learning as much about narcolepsy as possible and finding a
support system can help patients and families deal with the
practical and emotional effects of the disease, possible
occupational limitations, and situations that might cause injury. A
variety of educational and other materials are available from sleep
medicine or narcolepsy organizations. Support groups exist to help
persons with narcolepsy and their families. Individuals with
narcolepsy, their families, friends, and potential employers should
- Narcolepsy is a life-long condition that requires continuous
- Although there is not a cure for narcolepsy at present, several
medications can help reduce its symptoms.
- People with narcolepsy can lead productive lives if they are
provided with proper medical care.
- If possible, individuals with narcolepsy should avoid jobs that
require driving long distances or handling hazardous equipment or
that require alertness for lengthy periods.
- Parents, teachers, spouses, and employers should be aware of
the symptoms of narcolepsy. This will help them avoid the mistake
of confusing the person's behavior with laziness, hostility,
rejection, or lack of interest and motivation. It will also help
them provide essential support and cooperation.
- Employers can promote better working opportunities for
individuals with narcolepsy by permitting special work schedules
and nap breaks.