What Is Narcolepsy?

Symptoms of narcolepsy

You may have any of the following symptoms:

• Excessive daytime sleepiness (EDS). People with narcolepsy have an urge to frequently nap. They feel rested for only a short period after naps, then are sleepy again.

• Sleep attacks. These occur without warning and are hard to resist.

• Cataplexy. A sudden loss of muscle control or tone. It's often triggered by stress or emotion, such as laughter, fear, or anger.

• Sleep paralysis. A feeling of not being able to talk or move for a short time. It may occur when a person is falling asleep or waking up.

• Hallucinations. These are certain images, sensations, or sounds that occur when a person is falling asleep (hypnagogic) or waking up (hypnopompic). 

• Other symptoms. These can include difficulty staying asleep at night, insomnia, fatigue, poor memory and concentration, or depression.

Understanding REM sleep and its link to narcolepsy 

REM (rapid eye movement) is the part of sleep when you dream. REM sleep usually starts after the first 60 to 90 minutes. REM sleep starts much sooner for people with narcolepsy. This is usually within 15 minutes of sleep. This can make dreaming so vivid, it seems real. 

Many symptoms of narcolepsy are caused by REM sleep intruding into wakefulness. During REM sleep, people are normally paralyzed. Waking out of REM sleep results in sleep paralysis. Cataplexy is a sudden loss of muscle tone, as would occur during REM sleep. The hallucinations you may have when falling asleep or waking up are based on dreaming during REM sleep. You then wake up and see the dream continuing with your eyes open.