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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. Less than one-third of people who have narcolepsy have all four symptoms.

Extreme Daytime Sleepiness

All people who have narcolepsy have extreme daytime sleepiness. This often is 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 anger, fear, laughter, or excitement—can trigger this sleepiness.

People who have daytime sleepiness often complain of:

  • Mental cloudiness or "fog"
  • Memory problems or problems focusing
  • Lack of energy or extreme exhaustion
  • Depression

Some people who have narcolepsy have 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.


This condition causes loss of muscle tone while you're awake. Muscle weakness affects part or all of your 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 anger, surprise, fear, or laughter—often trigger cataplexy. 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.


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 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 do 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.

Children who have narcolepsy may have severe sleepiness. They may fall asleep while talking or eating, or during sporting events and social activities.

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November 01, 2010 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.