If someone suffers from narcolepsy, they may fall asleep at any moment of the day. They will also experience excessive sleepiness. This condition is a neurological disorder, which is linked to the production of chemicals in the brain that signal sleep cycles. Typical, or normal, sleep cycles begin with early sleep, deeper sleep, than REM (Rapid eye movement) sleep. With narcolepsy, the REM sleep cycle occurs immediately in the sleep cycles, as well as in the waking hours which is shy they can fall asleep so suddenly, no matter what activity they may be undertaking.
Narcolepsy is often undiagnosed. Sufferers usually show the signs between ages 15 and 25; it's not just falling asleep suddenly. They may also experience cataplexy which is the loss of voluntary muscle control, hallucinations and sleep paralysis, which can last from a few second to a few minutes as they are falling asleep or waking up.
Medication, lifestyle adjustments and regulating a sleep schedule for the daytime naps can help to control the symptoms of narcolepsy, but it will not be able to cure it completely.