What Is Narcolepsy?
Narcolepsy is a chronic (long-lasting) neurological (affecting the brain or nerves) disorder that involves
your body's central nervous system. The central nervous system is the "highway" of nerves that carries
messages from your brain to other parts of your body. 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, 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 awakenings.
Three other classic symptoms of narcolepsy, which may not occur in all patients, are:
Cataplexy: 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 minutes.
Hypnogogic hallucinations: vivid, often frightening, dreamlike experiences that occur while dozing or
falling asleep.
Daytime sleepiness, sleep paralysis, and hypnogogic hallucinations, and even cataplexy can also
occur in people who do not have narcolepsy.
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, may
become severe enough to cause serious disruptions in a person's social, personal, and professional
lives and severely limit activities.
When Should You Suspect Narcolepsy?
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 shocked; * you find yourself
briefly unable to talk or move while falling asleep or waking up.
How Common Is Narcolepsy?
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 Narcolepsy?
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. Recent discoveries
indicate that people with narcolepsy lack a chemical in the brain called hypocretin, which normally
stimulates arousal and helps regulate sleep. They also discovered that there is a reduction in the
number of Heart cells or neurons that secrete hypocretin. This may be due to a degenerative process
or an immune response. How this occurs is unknown
About one in 2,000 people suffers from narcolepsy. It affects both men and women of any age, but its
symptoms are usually noticed after puberty begins. For the majority of persons with narcolepsy, their
first symptoms appear between the ages of 15 and 30.
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 Narcolepsy 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 polysomnogram and 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 Narcolepsy 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 medications, but lifestyle changes 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.
Doctors generally prescribe stimulants to improve alertness and antidepressants to control cataplexy,
hypnagogic hallucinations and sleep paralysis.
Common stimulants include: dextroamphetamine sulfate (Dexedrine™), methylphenidate
hydrochloride (Ritalin™), and pemoline (Cylert™). Methamphetamine hydrochloride (Desoxyn™) is
prescribed less frequently for narcolepsy. Some of the most common side effects of stimulants are
headache, irritability, nervousness, insomnia, irregular heart beat, and mood changes. A newer, wake-
promoting drug, modafinil (Provigil™) was approved by the U.S. Food and Drug Administration (FDA) in
1999 for use in treating the excessive daytime sleepiness associated with narcolepsy. It does not act
as a stimulant for other body systems and studies have shown that modafinil is effective in improving
alertness with few side effects and low abuse potential.
Several classes of antidepressants are prescribed to treat cataplexy, hypnagogic hallucinations and
sleep paralysis. One class, multicyclics, includes imipramine (Tofranil™), desimpramine
(Norpramin™), clomipramine (Anafranil™), and protriptyline (Vivactil™). Another class are selective
serotonin re-uptake inhibitors (SSRIs). These include fluoxetine (Prozac™), paroxetine (Paxil™), and
sertraline (Zoloft™).
Side effects vary from one class of antidepressants to another. Those most often reported are
drowsiness, sexual dysfunction and lowered blood pressure. In a small percentage of patients, SSRIs
cause over excitement, anxiety, insomnia, nausea and reduced sexual drive. Sodium oxybate
(Xyrem™), also known as gamma-hydroxybutyrate or GHB is a medication used to control the
symptoms of cataplexy, sleep-associated hallucinations and sleep paralysis. It improves nighttime
sleep, which may contribute to decreased daytime drowsiness and less cataplexy.
Narcolepsy patients who have other health conditions (like high blood pressure, heart disease or
diabetes) should ask their doctor or pharmacist how medications for those conditions may interact
with those taken for narcolepsy. If you take over-the-counter cold and allergy medications, keep in mind
that they may make you sleepy.
In addition to drug therapy, an important part of treatment is scheduling short naps (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 control.
What Is Being Done To Better Understand Narcolepsy?
Studies supported by the National Institutes of Health (NIH) are trying to increase understanding of
what causes narcolepsy and improve physicians' ability to detect and treat the disease. Scientists are
studying narcolepsy patients and families, looking for clues to the causes, course, and effective
treatment of this sleep disorder. Recent discovery of families of dogs that are naturally afflicted with
narcolepsy has been of great help in these studies. Some of the specific questions being addressed
in NIH-supported studies are the nature of genetic and environmental factors that might combine to
cause narcolepsy and the immunological, biochemical, physiological, and neuromuscular
disturbances associated with narcolepsy. Scientists are also working to better understand sleep
mechanisms and the physical and psychological effects of sleep deprivation and to develop better
ways of measuring sleepiness and cataplexy.
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 know that: *
Narcolepsy is a life-long condition that requires continuous medication. * 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.
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