Symptoms

The signs and symptoms of narcolepsy may worsen for the first few years and then continue for life. They include:

• Excessive daytime sleepiness. People with narcolepsy fall asleep without warning, anywhere, anytime. For example, you may be working or talking with friends and suddenly you nod off, sleeping for a few minutes up to a half-hour. When you awaken, you feel refreshed, but eventually you get sleepy again.

  You may also experience decreased alertness and focus throughout the day. Excessive daytime sleepiness usually is the first symptom to appear and is often the most troublesome, making it difficult for you to concentrate and fully function.

• Sudden loss of muscle tone. This condition, called cataplexy (KAT-uh-plek-see), can cause a number of physical changes, from slurred speech to complete weakness of most muscles, and may last up to a few minutes.

  Cataplexy is uncontrollable and is triggered by intense emotions, usually positive ones such as laughter or excitement, but sometimes fear, surprise or anger. For example, when you laugh, your head may droop uncontrollably or your knees may suddenly buckle.

  Some people with narcolepsy experience only one or two episodes of cataplexy a year, while others have numerous episodes daily. Not everyone with narcolepsy experiences cataplexy.

• Sleep paralysis. People with narcolepsy often experience a temporary inability to move or speak while falling asleep or upon waking. These episodes are usually brief — lasting a few seconds or minutes — but can be frightening. You may be aware of the condition and have no difficulty recalling it afterward, even if you had no control over what was happening to you.

  This sleep paralysis mimics the type of temporary paralysis that normally occurs during a period of sleep called rapid eye movement (REM) sleep. This temporary immobility during REM sleep may prevent your body from acting out dream activity.

  Not everyone with sleep paralysis has narcolepsy, however. Many people without narcolepsy experience some episodes of sleep paralysis.

• Changes in rapid eye movement (REM) sleep. REM sleep is typically when most dreaming happens. REM sleep can occur at any time of the day in people with narcolepsy. People with narcolepsy often transition quickly to REM sleep, usually within 15 minutes of falling asleep.
• Hallucinations. These hallucinations are called hypnagogic hallucinations if they happen as you fall asleep and hypnopompic hallucinations if they occur upon waking. An example is feeling as if there is a stranger in your bedroom. These hallucinations may be particularly vivid and frightening because you may not be fully asleep when you begin dreaming and you experience your dreams as reality.

Other characteristics

People with narcolepsy may have other sleep disorders, such as obstructive sleep apnea — a condition in which breathing starts and stops throughout the night — restless legs syndrome and even insomnia.

Some people with narcolepsy experience automatic behavior during brief episodes of narcolepsy. For example, you may fall asleep while performing a task you normally perform, such as writing, typing or driving, and you 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.