Kate: "He has narcolepsy."
Constance: "He steals a lot?"
Sticky: "That's kleptomania. Mr. Benedict sleeps a lot."
Sticky and Kate informing Constance of Mr. Benedict's narcolepsy

Narcolepsy is a medical condition. It causes a person to fall asleep after a strong burst of emotion. Known characters who suffer from this aliment are Mr. Benedict, Mr. Curtain and their parents.

This is a fact that the Mysterious Benedict Society has had considerable trouble with, as shown in The Mysterious Benedict Society and the Perilous Journey when Mr. Benedict falls asleep while they are trying to escape. However, it has also worked to their advantage such as allowing them to trigger Mr. Curtain's narcolepsy so they could disable the Whisperer in The Mysterious Benedict Society.