What Is Narcolepsy?

Narcolepsy is a chronic sleep disorder that involves the central nervous system. People with narcolepsy may have sleep attacks that come on without warning. Narcolepsy almost always shows up in younger people. But it can also appear later in life. It can be diagnosed by a healthcare provider or a sleep specialist.

Symptoms of narcolepsy

You may have any of the following symptoms:

• Excessive daytime sleepiness (EDS). You want to sleep all day long.

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

• Cataplexy. A sudden loss of muscle control or tone. It is 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 insomnia, fatigue, poor memory and concentration, or depression.

Understanding REM sleep and its link to narcolepsy 

REM (rapid eye movement) is the dreaming portion of sleep. Usually, REM sleep begins after the first 90 minutes. For people with narcolepsy, REM sleep begins much sooner. 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.