What Is Narcolepsy?

Narcolepsy is a rare sleep disorder that affects the brain’s ability to control sleep-wake cycles. Rapid eye movement (REM) sleep typically occurs within an hour of falling asleep. For individuals with narcolepsy, REM sleep can happen within minutes of falling asleep, causing the sleep cycle to become unregulated. This can lead to excessive daytime sleepiness, where individuals experience an intense urge to sleep that can happen without warning, sleep paralysis, hallucinations, and fragmented sleep.Footnote1

What Is Narcolepsy Type 1?

Narcolepsy type 1 (NT1) is caused by a deficiency in a substance known as hypocretin, also called orexin. Due to this deficiency, the immune system attacks the neurons that produce orexin. In addition to excessive daytime sleepiness, this can also lead to cataplexy, which is when muscles become temporarily weak, and can cause an individual to lose their ability to move or control their muscles. Cataplexy can be triggered through emotions like laughter or surprise. Cataplectic attacks can range from minor, such as affecting the face, to major, such as causing an individual’s whole body to become weak.Footnote2

What is Narcolepsy Type 2?

Individuals with narcolepsy type 2 (NT2) do not experience cataplexy, but they still have symptoms that are typical of narcolepsy, including excessive daytime sleepiness. Unlike NT1, where individuals have deficient orexin levels, orexin levels are normal in NT2. The cause of NT2 is still unknown.Footnote2

References

  1. sleepfoundation.org
  2. mountsinai.org