Narcolepsy is a sleep disorder that makes people very drowsy during the day. People with narcolepsy find it hard to stay awake for long periods of time. They fall asleep suddenly. This can cause serious problems in their daily routine.

Sometimes narcolepsy also causes a sudden loss of muscle tone, known as cataplexy (KAT-uh-plek-see). This can be triggered by strong emotion, especially laughter. Narcolepsy is divided into two types. Most people with type 1 narcolepsy have cataplexy. Most people who don't have cataplexy have type 2 narcolepsy.

Narcolepsy is a life-long condition for which there's no cure. However, medicines and lifestyle changes can help manage the symptoms. Support from others — family, friends, employers and teachers — can help people cope with the disorder.

The symptoms of narcolepsy may get worse during the first few years of the disorder. Then they continue for life. They include:

• Excessive daytime sleepiness. People with narcolepsy fall asleep without warning. It can happen anywhere and at any time. It may happen when you're bored or during a task. For example, you may be working or talking with friends and suddenly fall asleep. It can be especially dangerous if you fall asleep while driving. You might fall asleep for only a few minutes or up to a half-hour. After waking, you'll often feel refreshed but you'll get sleepy again.

  You also may experience a decrease in how alert and focused you feel during the day. Daytime sleepiness often is the first symptom to appear. Feeling sleepy makes it hard to focus and function.

  Some people with narcolepsy continue doing a task when they fall asleep briefly. For example, you may fall asleep while writing, typing or driving. You might continue to perform that task while asleep. When you awaken, you can't remember what you did, and you probably didn't do it well.

• Sudden loss of muscle tone. This condition is called cataplexy. It can cause slurred speech or complete weakness of most muscles. Symptoms may last up to a few minutes.

  Cataplexy can't be controlled. It's triggered by intense emotions. Often the emotions that cause cataplexy are positive. Laughter or excitement may cause the symptoms. But sometimes fear, surprise or anger can cause the loss of muscle tone. For example, when you laugh, your head may drop without your control. Or your knees may suddenly lose strength, causing you to fall.

  Some people with narcolepsy experience only one or two episodes of cataplexy a year. Others have several episodes a day. Not everyone with narcolepsy has these symptoms.

• Sleep paralysis. People with narcolepsy often experience sleep paralysis. During sleep paralysis, you can't move or speak while falling asleep or upon waking. It's usually brief — lasting a few seconds or minutes. But it can be scary. You may be aware of it happening and can recall it afterward.

  Not everyone with sleep paralysis has narcolepsy.

• Hallucinations. Sometimes people see things that aren't there during sleep paralysis. Hallucinations also may happen in bed without sleep paralysis. These are called hypnagogic hallucinations if they happen as you fall asleep. They're called hypnopompic hallucinations if they happen upon waking. For example, you might feel as if there is a stranger in your bedroom. These hallucinations may be vivid and frightening because you may not be fully asleep when you begin dreaming.
• Changes in rapid eye movement (REM) sleep. REM sleep is when most dreaming happens. Typically, people enter REM sleep 60 to 90 minutes after falling asleep. But people with narcolepsy often move more quickly to REM sleep. They tend to enter REM sleep within 15 minutes of falling asleep. REM sleep also can happen at any time of the day.

Other characteristics

People with narcolepsy may have other sleep disorders. They might have obstructive sleep apnea, in which breathing starts and stops during the night. Or they may act out their dreams, known as REM sleep behavior disorder. Or they may have trouble falling asleep or staying asleep, called insomnia.

When to see a doctor

See your health care provider if you experience excessive daytime sleepiness that affects your personal or professional life.

The exact cause of narcolepsy is unknown. People with type 1 narcolepsy have low levels of hypocretin (hi-poe-KREE-tin), also called orexin. Hypocretin is a chemical in the brain that helps control being awake and when you enter REM sleep.

Hypocretin levels are low in people who experience cataplexy. Exactly what causes the loss of hypocretin-producing cells in the brain isn't known. But experts suspect it's due to an autoimmune reaction. An autoimmune reaction is when the body's immune system destroys its own cells.

It's also likely that genetics plays a role in narcolepsy. But the risk of a parent passing this disorder to a child is very low — only about 1% to 2%.

Research also indicates that in some cases narcolepsy may be linked to exposure to the swine flu (H1N1 flu) virus. It also may be linked to a certain form of the H1N1 vaccine. The vaccine was administered in Europe.

Typical sleep pattern vs. narcolepsy

The typical process of falling asleep begins with a phase called non-rapid eye movement (NREM) sleep. During this phase, brain waves slow. After an hour or so of NREM sleep, brain activity changes and REM sleep begins. Most dreaming occurs during REM sleep.

In narcolepsy, you may suddenly enter REM sleep without going through NREM sleep. This can happen both at night and during the day. Cataplexy, sleep paralysis and hallucinations are similar to changes that occur in REM sleep. But in narcolepsy they happen while you're awake or drowsy.

There are only a few known risk factors for narcolepsy, including:

• Age. Narcolepsy typically begins between ages 10 and 30.
• Family history. Your risk of narcolepsy is 20 to 40 times higher if you have a close family member who has it.

• Public misconception of the condition. Narcolepsy can cause problems at work or in your personal life. Your performance may suffer at school or work. Others might see people with narcolepsy as lazy or lethargic.
• Effects on intimate relationships. Intense feelings, such as anger or joy, can trigger cataplexy. This can cause people with narcolepsy to withdraw from emotional interactions.
• Physical harm. Falling asleep suddenly may result in injury. You're at increased risk of a car accident if you fall asleep while driving. Your risk of cuts and burns is greater if you fall asleep while cooking.
• Obesity. People with narcolepsy are more likely to be overweight. Sometimes weight rapidly increases when sleepiness symptoms start.

Your health care provider may suspect narcolepsy based on your symptoms of excessive daytime sleepiness and sudden loss of muscle tone, known as cataplexy. Your provider will likely refer you to a sleep specialist. Formal diagnosis requires staying overnight at a sleep center for an in-depth sleep analysis.

A sleep specialist will likely diagnose narcolepsy and determine how severe it is based on:

• Your sleep history. A detailed sleep history can help with a diagnosis. You'll likely fill out the Epworth Sleepiness Scale. The scale uses short questions to measure your degree of sleepiness. You'll answer how likely it is that you would fall asleep in certain times, such as sitting down after lunch.

• Your sleep records. You may be asked to write down your sleep pattern for a week or two. This allows your provider to compare how your sleep pattern may relate to how alert you feel.

  Your health care provider also may ask you to wear an actigraph. This device is worn like a watch. It measures periods of activity and rest. It provides an indirect measure of how and when you sleep.

• A sleep study, known as polysomnography. This test measures signals during sleep using flat metal discs called electrodes placed on your scalp. For this test, you must spend a night at a medical facility. The test measures your brain waves, heart rate and breathing. It also records your leg and eye movements.
• Multiple sleep latency test. This test measures how long it takes you to fall asleep during the day. You'll be asked to take four or five naps at a sleep center. Each nap needs to be two hours apart. Specialists will observe your sleep patterns. People who have narcolepsy fall asleep easily and enter into rapid eye movement (REM) sleep quickly.
• Genetic tests and a lumbar puncture, known as a spinal tap. Occasionally, a genetic test may be performed to see if you're at risk of type 1 narcolepsy. If so, your sleep specialist may recommend a lumbar puncture to check the level of hypocretin in your spinal fluid. This test is only done in specialized centers.

These tests also can help rule out other possible causes of your symptoms. Excessive daytime sleepiness could also be caused by sleep deprivation, the use of sedating medicines and sleep apnea.

There is no cure for narcolepsy, but medicines and lifestyle changes can help you manage the symptoms.

Medications

Medicines for narcolepsy include:

• Stimulants. Drugs that stimulate the central nervous system are the primary treatment to help people with narcolepsy stay awake during the day. Your health care provider may recommend modafinil (Provigil) or armodafinil (Nuvigil). These medicines aren't as habit-forming as older stimulants. They also don't produce the highs and lows associated with older stimulants. Side effects are uncommon but may include headache, nausea or anxiety.

  Solriamfetol (Sunosi) and pitolisant (Wakix) are newer stimulants used for narcolepsy. Pitolisant also may be helpful for cataplexy.

  Some people need treatment with methylphenidate (Ritalin, Concerta, others) or amphetamines (Adderall XR 10, Dexedrine, others). These medicines are effective but can be habit-forming. They may cause side effects such as nervousness and a fast heartbeat.

• Serotonin and norepinephrine reuptake inhibitors (SNRIs) or selective serotonin reuptake inhibitors (SSRIs). These medicines suppress REM sleep. Health care providers prescribe these medicines to help ease the symptoms of cataplexy, hallucinations and sleep paralysis.

  They include venlafaxine (Effexor XR), fluoxetine (Prozac) and sertraline (Zoloft). Side effects can include weight gain, insomnia and digestive problems.

• Tricyclic antidepressants. These older antidepressants can treat cataplexy. But they can cause side effects such as dry mouth and lightheadedness. These medicines include protriptyline, imipramine (Tofranil) and clomipramine (Anafranil).

• Sodium oxybate (Xyrem) and oxybate salts (Xywav). These medicines work well at relieving cataplexy. They help improve nighttime sleep, which is often poor in narcolepsy. They also may help control daytime sleepiness. It's taken in two doses, one at bedtime and one up to four hours later.

  Xywav is a newer formulation with less sodium.

  These medicines can have side effects, such as nausea, bed-wetting and sleepwalking. Taking them together with other sleeping tablets, narcotic pain relievers or alcohol can lead to trouble breathing, coma and death.

If you take medicines for other health problems, ask your health care provider how they may interact with narcolepsy medicines.

Certain medicines that you can buy without a prescription can cause drowsiness. They include allergy and cold medicines. If you have narcolepsy, your doctor may recommend that you don't take these medicines.

Researchers are studying other potential treatments for narcolepsy. Medicines being studied include those that target the hypocretin chemical system. Researchers also are studying immunotherapy. Further research is needed before these medicines become available.

Lifestyle changes are important in managing the symptoms of narcolepsy. You may benefit if you:

• Stick to a schedule. Go to sleep and wake up at the same time every day, including weekends.
• Take naps. Schedule short naps at regular intervals during the day. Naps of 20 minutes during the day may be refreshing. They also may reduce sleepiness for 1 to 3 hours. Some people may need longer naps.
• Avoid nicotine and alcohol. Using these substances, especially at night, can worsen your symptoms.
• Get regular exercise. Plan for moderate, regular exercise at least 4 to 5 hours before bedtime. It may help you sleep better at night and feel more awake during the day.

Dealing with narcolepsy can be a challenge. Consider these tips:

• Talk about it. Tell your employer or teachers about your condition. Then work with them to find ways to adjust to your needs. This may include taking naps during the day. Or you might break up repetitive tasks. You might record meetings or classes to refer to later. You also might find it helps to stand during meetings or lectures, and to take brisk walks during the day.

  The Americans with Disabilities Act prohibits discrimination against workers with narcolepsy. Employers are required to provide reasonable accommodation to qualified employees.

• Be safe while driving. If you must drive a long distance, work with your health care provider to find ways to make a safe trip. Create a medicine schedule that is most likely to keep you awake during your drive. Stop for naps and exercise breaks whenever you feel drowsy. Don't drive if you feel too sleepy.

Support groups and counseling can help you and your loved ones cope with narcolepsy. Ask your health care provider to help you locate a group or qualified counselor in your area.

You're likely to start by seeing your primary care provider. But if narcolepsy is suspected, you may be referred to a sleep specialist.

Here's some information to help you prepare for your appointment.

What you can do

• Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance.
• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down key personal information, including any major stresses or recent life changes.
• Make a list of all medicines, vitamins or supplements you're taking.
• Ask a family member or friend to go with you. Sometimes it can be difficult to recall all the information you get during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Write down questions to ask your health care provider.

Preparing a list of questions for your provider will help you make the most of your time together. List your questions from most important to least important. For narcolepsy, some basic questions to ask your doctor include:

• What's the most likely cause of my symptoms?
• Are there other possible causes?
• What kinds of tests do I need?
• Do I need a sleep study?
• Is my condition likely temporary or long lasting?
• What treatment do you recommend?
• What are the alternatives to the primary approach you're suggesting?
• I have these other health conditions. How can I best manage these conditions together?
• Is there a generic alternative to the medicine you're prescribing?
• Are there any brochures or other printed material that I can take home with me? What websites do you recommend?

Don't hesitate to ask other questions anytime during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, including:

• When did you begin experiencing symptoms?
• Have your symptoms been continuous or occasional?
• How often do you fall asleep during the day?
• How severe are your symptoms?
• Does anything improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• Does anyone in your family have similar symptoms?