2. A sleep disorder that usually appears in young adulthood, consisting of recurring episodes of sleep during the day, and often disrupted nocturnal sleep: Quite often, narcolepsy is accompanied by sleep paralysis and hallucinations.
![Example of man on TV with narcolepsy.](http://www.wordinfo.info/words/images/Sleep-control.gif)
Sometimes narcolepsy is described as "sleep attack"
There are times when narcolepsy, or severe sleepiness, occurs so suddenly and with such overwhelming power that it is referred to as a "sleep attack".
Some victims have several "attacks" each day. Excessive daytime sleepiness often occurs at inopportune times: in the classroom, at business meetings, during a meal, in the middle of a conversation, or even when active before an audience of people; such as, an announcer on TV as shown in the above image.
Narcolepsy is a chronic neurological disorder caused by the brain's inability to regulate sleep-wake cycles normally.
At various times throughout the day, people with narcolepsy experience fleeting urges to sleep. If the urge becomes overwhelming, individuals will fall asleep for periods lasting from a few seconds to several minutes.
![An uncontrollable condition of falling asleep.](http://www.wordinfo.info/words/images/narcolepsy-1.jpg)