Why do people with narcolepsy suddenly fall asleep?

Narcolepsy is a condition where people have difficulty controlling when they fall asleep and wake up. This happens because of a problem with chemicals in the brain called hypocretins. These chemicals help keep us awake and regulate sleep cycles. When they don't work right, people can suddenly fall asleep during the day.

There are a few things that happen in narcolepsy:

1. Hypocretin Deficiency: The brain doesn't make enough hypocretins, which are important for staying awake.
2. Sleep Attacks: Because of the lack of hypocretins, people can fall asleep suddenly, even if they are in the middle of doing something.
3. Cataplexy: Some people with narcolepsy also have cataplexy, which is when muscles suddenly become weak, often triggered by strong emotions.

Understanding these changes in the brain helps explain why people with narcolepsy have trouble staying awake and can fall asleep without warning.