Narcolepsy is a chronic neurological disorder affecting sleep patterns and characterized by excessive sleepiness during the day and sudden onset of sleep. The cause of narcolepsy is not known, but it is thought to be linked to low levels of the chemical hypocretin in the brain. An estimated one in 2,000 people suffers from narcolepsy, which equates to around 200,000 Americans. 

Symptoms of narcolepsy include excessive sleepiness during the day, attacks of sleep, sleep paralysis, hallucinations, disruptions to nighttime sleep, and cataplexy. Cataplexy, which affects approximately seven out of ten people with narcolepsy, is the sudden loss of muscle tone, which can lead to muscle weakness or loss of muscle control. It is typically triggered by laughter or a strong emotion. Narcolepsy is often accompanied by other sleep disorders such as obstructive sleep apnea.

There is no cure for narcolepsy, but the condition is treatable with lifestyle changes and medication. Physicians may recommend sticking to a sleep schedule, taking regular naps throughout the day and getting plenty of exercise as methods of promoting healthy sleep. Drug classes used to treat narcolepsy are narcolepsy agents, psychostimulants, amphetamines, psychostimulants, methylphenidate derivatives, ADHD agents, stimulant, and other psychostimulants, and psychostimulants, amphetamines.