What Is Narcolepsy?
Narcolepsy (NAR-ko-lep-se) is a disorder that causes
periods of extreme daytime sleepiness. It also may cause muscle weakness.
Rarely, people who have this disorder fall asleep
suddenly, even if they're in the middle of talking, eating, or another
activity. Most people who have narcolepsy also have trouble sleeping at
night.
Narcolepsy also may cause:
- Cataplexy (KAT-a-plek-se). This condition causes
a sudden loss of muscle tone while you're awake. Muscle weakness can occur in
certain parts of your body or in your whole body. For example, if cataplexy
affects your hand, you may drop what you're holding. Strong emotions often
trigger this weakness. It may last seconds or minutes.
- Hallucinations (ha-lu-si-NA-shuns). These vivid
dreams occur while falling asleep or waking up.
- Sleep paralysis (pah-RAL-i-sis). This condition
prevents you from moving or speaking while waking up and sometimes while
falling asleep. Sleep paralysis usually goes away within a few minutes.
Overview
The two main phases of sleep are nonrapid eye
movement (NREM) and rapid eye movement (REM). Most people are in the NREM phase
when they first fall asleep. After about 90 minutes of sleep, most people go
from NREM to REM sleep.
Dreaming occurs during the REM phase of sleep.
During REM, your muscles normally become limp. This prevents you from acting
out your dreams. (For more information on sleep cycles, see the National Heart,
Lung, and Blood Institute's
"Your
Guide to Healthy Sleep.")
People who have narcolepsy often fall into REM sleep
quickly and wake up directly from it. This is linked to vivid dreams while
waking up and falling asleep.
Hypocretin, a chemical in the brain, helps control
levels of wakefulness. Most people who have narcolepsy have low levels of this
chemical. What causes these low levels isn't well understood.
Researchers think that certain factors may work
together to cause a lack of hypocretin. Examples include heredity; brain
injuries; contact with toxins, such as pesticides; and autoimmune disorders.
(Autoimmune disorders occur when the body's immune system attacks the body's
healthy cells.)
Outlook
Narcolepsy affects between 50,000 and 2.4 million
people in the United States. Symptoms usually begin during the teen or young
adult years. Due to extreme tiredness, people who have narcolepsy may find it
hard to function at school, work, home, and in social situations.
Narcolepsy has no cure, but medicines, lifestyle
changes, and other therapies can improve symptoms. Research on the causes of
narcolepsy and new ways to treat it is ongoing.
What Causes Narcolepsy?
Most people who have narcolepsy have low levels of
hypocretin. This is a chemical in the brain that helps control levels of
wakefulness. What causes these low hypocretin levels isn't well understood.
Researchers think that certain factors may work
together to cause a lack of hypocretin. These factors may include:
- Heredity. Some people may inherit a gene that
affects hypocretin. Up to 10 percent of people who have narcolepsy
report having a relative with the same symptoms.
- Infections.
- Brain injuries due to conditions such as brain
tumors or strokes.
- Contact with toxins, such as pesticides.
- Autoimmune disorders. These are conditions in
which the body's immune system attacks the body's healthy cells. An example of
an autoimmune disorder is rheumatoid arthritis.
Heredity alone doesn't cause narcolepsy. You also
must have at least one other factor, such as one of those listed above, to
develop narcolepsy.
Who Is At Risk for Narcolepsy?
Narcolepsy affects between 50,000 and 2.4 million
people in the United States. Symptoms usually begin during the teen or young
adult years. The disorder also can develop later in life or in children, but
it's rare before age 5. Narcolepsy affects both men and women.
Researchers think that certain factors may work
together to cause narcolepsy. If these factors affect you, you may be at higher
risk for the disorder. (For more information, see
"What Causes Narcolepsy?")
What Are the Signs and Symptoms of Narcolepsy?
The four major signs and symptoms of narcolepsy are
extreme daytime sleepiness, cataplexy (muscle weakness) while awake, and
hallucinations and sleep paralysis during sleep.
If you have narcolepsy, you may have one or more of
these symptoms. They can range from mild to severe.
Extreme Daytime Sleepiness
All people who have narcolepsy have extreme daytime
sleepiness. This is often the most obvious symptom of the disorder.
During the day, you may have few or many periods of
sleepiness. Each period usually lasts 30 minutes or less. Strong emotions,
such as laughter, anger, fear, or excitement, can bring on this sleepiness.
People who have this symptom often complain of:
- Mental cloudiness or "fog"
- Memory problems or problems focusing
- Lack of energy or extreme exhaustion
- Depression
Rarely, people who have narcolepsy have sleep
episodes in which they fall asleep suddenly. This is more likely to happen when
they're not active—for example, while reading, watching TV, or sitting in
a meeting.
However, sleep episodes also may occur in the middle
of talking, eating, or another activity. Cataplexy also may occur at the same
time.
Cataplexy
This condition causes loss of muscle tone while
you're awake. Muscle weakness occurs in certain parts of your body or in your
whole body.
Cataplexy may make your head nod or make it hard for
you to speak. Muscle weakness also may make your knees weak or cause you to
drop things you're holding. Some people lose all muscle control and fall.
Strong emotions, such as laughter or excitement,
often trigger this symptom. It usually lasts a few seconds or minutes. During
this time, you're usually awake.
Cataplexy may occur weeks to years after you first
start to have extreme daytime sleepiness.
Hallucinations
If you have narcolepsy, you may have vivid dreams
while falling asleep, waking up, or dozing. These dreams can feel very real.
You may feel like you can see, hear, smell, and taste things.
Sleep Paralysis
This condition prevents you from moving or speaking
while falling asleep or waking up. However, you're fully conscious (aware)
during this time. Sleep paralysis usually lasts just a few seconds or minutes,
but it can be scary.
Other Symptoms
Most people who have narcolepsy also don't sleep
well at night. They may have trouble falling and staying asleep. Vivid, scary
dreams may disturb sleep. Not sleeping well at night worsens daytime
sleepiness.
Rarely, people who fall asleep in the middle of an
activity, such as eating, may continue that activity for a few seconds or
minutes. This is called automatic behavior.
During automatic behavior, you're not aware of your
actions, so you don't perform them well. For example, if you're writing before
falling asleep, you may scribble rather than form words. If you're driving, you
may get lost or have an accident. Most people who have this symptom don't
remember what happened while it was going on.
Children who have narcolepsy often have trouble
studying, focusing, and remembering things. Also, they may seem hyperactive.
Some children who have narcolepsy speed up their activities rather than slow
them down.
How Is Narcolepsy Diagnosed?
It can take as long as 10 to 15 years after the
first symptoms appear before narcolepsy is recognized and diagnosed. This is
because narcolepsy is fairly rare. Also, many of the symptoms of narcolepsy are
like symptoms of other illnesses, such as infections, depression, and sleep
disorders.
Narcolepsy is sometimes mistaken for learning
problems, seizure disorders, or laziness, especially in school-aged children
and teens. When narcolepsy symptoms are mild, it's even harder to diagnose.
Your doctor will diagnose narcolepsy based on your
signs and symptoms, your medical and family histories, a physical exam, and
results from tests.
Signs and Symptoms
Tell your doctor about any signs and symptoms of
narcolepsy that you have. This is important because your doctor may not ask
about them during a routine checkup.
Your doctor will want to know when you first had
signs and symptoms and whether they bother your sleep or daily routine. He or
she also will want to know about your sleep habits and how you feel and act
during the day.
To help answer these questions, you may want to keep
a sleep diary for a few weeks. Keep a daily record of how easy it is to fall
and stay asleep, how much sleep you get at night, and how alert you feel during
the day.
For a sample sleep diary, see the National Heart,
Lung, and Blood Institute's
"Your
Guide to Healthy Sleep."
Medical and Family Histories
To learn about your medical and family histories,
your doctor may ask whether:
- You're affected by certain factors that can lead
to narcolepsy. These include infection, brain injuries, contact with toxins
(such as pesticides), or autoimmune disorders.
- You take medicines and which ones you take. Some
medicines can cause daytime sleepiness. Thus, your symptoms may be due to
medicine, not narcolepsy.
- You have symptoms of other sleep disorders that
cause daytime sleepiness.
- You have relatives who have narcolepsy or who
have signs or symptoms of the disorder.
Physical Exam
Your doctor will examine you to see whether another
condition is causing your symptoms. For example, infections, certain thyroid
diseases, drug and alcohol use, and other medical or sleep disorders may cause
symptoms similar to those of narcolepsy.
Diagnostic Tests
Sleep Studies
If your doctor thinks you have narcolepsy, he or she
will likely suggest that you see a sleep specialist. This specialist may advise
you to have special
sleep
studies to find out more about your condition.
Sleep studies usually are done at a sleep center.
The results of two tests—a polysomnogram (PSG) and a multiple sleep
latency test (MSLT)—are used to diagnose narcolepsy.
Polysomnogram. You usually stay
overnight at a sleep center for a PSG. The test records brain activity, eye
movements, breathing, heart rate, and blood pressure. This test can help find
out whether you:
- Fall asleep quickly
- Go into rapid eye movement (REM) sleep soon after
falling asleep
- Wake up often during the night
Multiple sleep latency test. This
daytime sleep study measures how sleepy you are. It's often done the day after
a PSG. During the test, you relax in a quiet room for about 30 minutes. A
technician checks your brain activity during this time. The test is repeated
three or four times throughout the day.
An MSLT finds out how quickly you fall asleep during
the day (after a full night's sleep). It also shows whether you go into REM
sleep soon after falling asleep.
Other Tests
Hypocretin test. This test measures
the levels of hypocretin in the fluid that surrounds your spinal cord. Most
people who have narcolepsy have low levels of hypocretin.
To get a sample of spinal cord fluid, a spinal tap
(also called a lumbar puncture) is done. For this procedure, your doctor
inserts a needle into your lower back area and then withdraws a sample of your
spinal fluid.
How Is Narcolepsy Treated?
Narcolepsy has no cure. However, medicines,
lifestyle changes, and other therapies can relieve many of its symptoms.
Treatment for narcolepsy is based on the type of symptoms you have and how
severe they are.
Not all medicines and lifestyle changes work for
everyone. It may take weeks to months for you and your doctor to find the best
treatment.
Medicines
You may need one or more medicines to treat
narcolepsy symptoms. These may include:
- Stimulants to ease daytime sleepiness and raise
your alertness.
- A medicine that helps make up for the low levels
of hypocretin in your brain. (Hypocretin is a chemical that helps control
levels of wakefulness.) This medicine helps you stay awake during the day and
sleep at night. It doesn't always completely relieve daytime sleepiness, so
your doctor may tell you to take it with a stimulant.
- Medicines that help you sleep at night.
- Medicines used to treat depression. These
medicines also help prevent cataplexy, hallucinations, and sleep
paralysis.
Some prescription and over-the-counter medicines can
interfere with your sleep. Ask your doctor about these medicines and how to
avoid them, if possible.
If you take regular naps when you feel sleepy, you
may need less medicine to stay awake.
Lifestyle Changes
Lifestyle changes also may help relieve some
narcolepsy symptoms. You can take steps to make it easier to fall asleep at
night and stay asleep.
- Follow a regular sleep schedule. Go to bed and
wake up at the same time every day.
- Do something relaxing before bedtime, such as
taking a warm bath.
- Keep your bedroom or sleep area quiet,
comfortable, dark, and free from distractions, such as a TV or computer.
- Allow yourself about 20 minutes to fall asleep or
fall back asleep after waking up. After that, get up and do something relaxing
(like reading) until you get sleepy.
Certain activities, foods, and drinks before bedtime
can keep you awake. Try to follow these guidelines:
- Exercise regularly, but not within 3 hours of
bedtime.
- Avoid tobacco, alcohol, chocolate, and drinks
that contain caffeine for several hours before bedtime.
- Avoid large meals and beverages just before
bedtime.
- Avoid bright lights before bedtime.
For more tips on sleeping better, see the National
Heart, Lung, and Blood Institute's
"Your
Guide to Healthy Sleep."
Other Therapies
Light therapy may help you keep a regular sleep and
wake schedule. For this type of therapy, you sit in front of a light box, which
has special lights, for 10 to 30 minutes. This therapy can help you feel less
sleepy in the morning.
Living With Narcolepsy
Living with narcolepsy can be hard. It can affect
your ability to drive, work, go to school, and have relationships. Besides
taking medicine, you can do many things to live a safe and satisfying life.
Driving
Driving can be dangerous for people who have
narcolepsy. Ask your doctor whether you can drive safely. To help make it safer
for you to drive:
- Take naps before driving. This helps some people
who have periods of extreme daytime sleepiness.
- Stop often during long drives. Stretch and walk
around during the stops.
- Try to have family, friends, or coworkers in the
car to keep you aware and engaged, or get rides from them.
Working
People who have narcolepsy can work in almost all
types of jobs, but some jobs may be better than others. For example, a job with
a flexible work schedule can make it easier to take naps when needed. A job in
which you interact with your coworkers can help keep you awake. Jobs that don't
require you to drive or are closer to home also may be better.
Certain laws may apply to workers who have medical
conditions, such as narcolepsy. These laws include the:
- Americans with Disabilities Act (ADA). This law
requires employers to reasonably accommodate the needs of their workers who
have disabilities. This includes people who have narcolepsy. For example,
employers may allow workers to take short naps during the workday or adjust
work schedules to avoid sleepy periods.
- Family and Medical Leave Act. This law requires
employers who have 50 or more employees to provide unpaid leave to employees
with an illness, such as narcolepsy. It also gives leave to family members who
need time to care for a close relative who has a serious illness.
- Social Security Disability Insurance or
Supplemental Security Income programs. These programs may offer financial help
if you can't work because of your narcolepsy.
Getting Emotional Support
Getting support from others—friends, family,
and coworkers—may help you cope with your disorder. Learn more about
narcolepsy, and tell your family and friends about the disorder. Ask them for
help.
Seek professional counseling for yourself and your
family. Ask your doctor about narcolepsy or sleep disorder support groups in
your area.
Narcolepsy in Special Groups
School-Aged Children
Children who have narcolepsy may have trouble
studying, focusing, and remembering things. To help your child in school:
- Talk to your child's teachers and school
administrators about your child's narcolepsy and the best ways to meet his or
her needs. For example, your child may need to take naps or walks during the
day or tape the teacher's lessons.
- Talk to the school nurse about your child's
narcolepsy and medicines. Together you can work out a place to keep the
medicines and a schedule for taking them at school.
Pregnant Women
If you're pregnant or planning a pregnancy, talk to
your doctor about whether you should continue taking your narcolepsy medicines.
Certain medicines may interfere with your pregnancy.
Key Points
- Narcolepsy is a disorder that causes periods of
extreme daytime sleepiness. Rarely, people who have this disorder fall asleep
suddenly during routine activities. Most people who have narcolepsy also have
trouble sleeping at night.
- Narcolepsy also may cause cataplexy,
hallucinations (vivid dreams) during sleep, and sleep paralysis. Sleep
paralysis is a condition that prevents you from moving or speaking while waking
up and sometimes while falling asleep. Cataplexy is a condition that causes
sudden loss of muscle tone while you're awake.
- People who have narcolepsy have low levels of
hypocretin. This is a chemical in the brain that helps control levels of
wakefulness. Researchers think that certain factors may work together to cause
a lack of hypocretin. Examples of these factors include heredity; brain
injuries; contact with toxins, such as pesticides; and autoimmune
disorders.
- Narcolepsy affects between 50,000 and 2.4 million
people in the United States. Symptoms usually begin during the teen or young
adult years. Narcolepsy affects both men and women.
- The four major signs and symptoms of narcolepsy
are extreme daytime sleepiness, cataplexy (muscle weakness) while awake, and
hallucinations and sleep paralysis during sleep. Most people who have
narcolepsy also don't sleep well at night. They may have trouble falling and
staying asleep. Vivid, scary dreams may disturb sleep.
- It can take as long as 10 to 15 years after the
first symptoms appear before narcolepsy is recognized and diagnosed. This is
because narcolepsy is fairly rare. Also, many of the symptoms of narcolepsy are
liked symptoms of other illnesses.
- Narcolepsy is diagnosed based on your signs and
symptoms, your medical and family histories, a physical exam, and results from
tests.
- Narcolepsy has no cure. However, medicines,
lifestyle changes, and other therapies can relieve many of its symptoms.
Treatment for narcolepsy is based on the type of symptoms you have and how
severe they are.
- Living with narcolepsy can be hard. It can affect
your ability to drive, work, go to school, and have relationships. Besides
taking medicine, you can do many things to live a safe and satisfying life.
Talk to your doctor about how to cope with your condition.
Links to Other Information About Narcolepsy
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
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