A sleep condition that causes people to feel very drowsy and to fall asleep suddenly.

The cause of narcolepsy is not known. But people with a family history of narcolepsy have a higher risk of having the condition. Narcolepsy usually begins between ages 10 and 30. In some people, narcolepsy is linked to the swine flu.

Narcolepsy makes people very sleepy. They can fall asleep without warning, even while talking or driving. They may have other sleep conditions too. Some people have a sudden loss of muscle tone when they laugh.

Healthcare professionals can prescribe medicines to help people stay awake during the day. Antidepressants and oxybate (Xyrem, Xywav, Lumryz) can help people with sudden loss of muscle tone and other sleep conditions. Going to sleep and waking up at the same time, scheduling naps, and exercising also help.