This disorder involves a lot more than falling asleep in the middle of a sentence.
Narcolepsy, which affects about one in 2,000 people, is a sleep disorder that causes a person to instantly fall into a deep sleep at any time, even in the middle of an activity. Those unplanned sleep attacks aren’t very long—usually just a few seconds to a few minutes—but they can have a huge impact on a person's quality of life.
Imagine falling asleep in the middle of chatting with your boss, eating dinner with your family, or driving a car. It’s not only embarrassing, it’s dangerous. On top of that, it’s a constant cycle that can leave a person feeling constantly groggy. After one of the sleep attacks, the person might feel rested, but before long, exhaustion sets in and the person suddenly falls asleep again. To make matters worse, those with narcolepsy don’t sleep very well at night and often wake up regularly.
Falling asleep suddenly isn’t the only symptom of narcolepsy. Most people with the disorder also experience something called excessive daytime sleepiness, which means having very low energy, being extremely exhausted, and feeling like there’s a persistent cloud over your brain all day long. Beyond that, 70 percent of people who have narcolepsy also have cataplexy, which causes muscles to go completely limp. Two rarer side effects of narcolepsy are sleep paralysis (when you can’t move at all just before falling asleep or just after you wake up) and hallucinations (vivid and frightening visions that are much more realistic than normal dreams).
Most cases of narcolepsy are caused by low levels of hypocretin, a neurotransmitter that is connected to wakefulness. That might explain why, when people with narcolepsy fall asleep, they go straight into REM sleep. (Most people don't enter REM for at least an hour after falling asleep.) Narcolepsy often starts between the ages of seven and 25 and is a lifelong disease.
There is no cure yet for narcolepsy, although there are some medications and behavioral changes that can help relieve symptoms. Doctors may prescribe stimulants to help a person stay alert during the day or other medications that help regulate sleep cycles. Lifestyle changes that can help include developing a strict sleep schedule, taking a nap each day, exercising regularly, and avoiding nicotine and alcohol.
To learn more about the science behind Narcolepsy