What is it?

Cataplexy is a sudden and transient episode of muscle weakness accompanied by full conscious awareness, typically triggered by emotions such as laughing, crying, or terror. Cataplexy affects approximately 70% of people who have narcolepsy - a neurological condition that causes extreme sleepiness during the day and unexpected episodes of falling asleep.
narcolepsy with cataplexy is caused by a lack of hypocretin (also called orexin) in your brain, a chemical which regulates arousal and has a role in stabilization of the transition between wake and sleep states. Cataplexy without narcolepsy is rare.