Narcolepsy (NAR-ko-lep-se) is a disorder that causes periods of extreme daytime sleepiness. The disorder also may cause muscle weakness.
Most people who have narcolepsy have trouble sleeping at night. Some people who have the disorder fall asleep suddenly, even if they’re in the middle of talking, eating, or another activity.
Narcolepsy also can cause:
• Cataplexy (KAT-ah-plek-se). This condition causes a sudden loss of muscle tone while you’re awake. Muscle weakness can affect certain parts of your body or your whole body. For example, if cataplexy affects your hand, you may drop what you’re holding. Strong emotions often trigger this weakness. It may last seconds or minutes.
• Hallucinations (ha-lu-sih-NA-shuns). These vivid dreams occur while falling asleep or waking up.
• Sleep paralysis (pah-RAL-ih-sis). This condition prevents you from moving or speaking while waking up and sometimes while falling asleep. Sleep paralysis usually goes away within a few minutes.