Narcolepsy is a lifelong sleep disorder that makes you feel overwhelmingly tired, and in severe cases, have sudden uncontrollable sleep attacks. Narcolepsy can impact nearly every aspect of your life. It is dangerous because you can have excessive sleepiness or a sleep attack at any time of the day, in the middle of any activity including eating, walking or driving. Operating a vehicle with untreated narcolepsy can be very dangerous and some states even have laws against it. Many people with narcolepsy do not know they have the sleep disorder. Nearly one in 2,000 people have some form of narcolepsy.