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. It is a symptom of narcolepsy, a sleep disorder that involves excessive daytime sleepiness. The loss of muscle tone that occurs during cataplexy may range from a just a weakening of the facial muscles to total collapse on the floor. The triggering experiences are usually positive, like laughter, witty conversations, and pleasant surprise, but episodes may also be triggered by anger, though rarely by stress, fear, or physical exertion. Cataplexy attacks generally last less than two minutes, and they may only last a few seconds, though some people have repeated attacks of cataplexy which persist for up to 30 minutes. During both mild and severe attacks, the person stays fully conscious.

Cataplexy is closely linked to a loss of hypocretin, an important role regulator of wakefulness in the brain. It is also associated with abnormalities in the immune system, which can cause the loss of brain cells that produce hypocretin. Cataplexy can be diagnosed by a healthcare provider based on the patients symptoms. There is no specific test to spot cataplexy.

While experiencing cataplexy can be a frightening experience, episodes aren’t considered to be dangerous so long as a person is in a safe place. Most people know when an episode is coming, giving them important time to sit or lie down. Between episodes, it may be helpful to take steps to ensure that the environment is safe for when episodes arise. For many people who experience cataplexy, lifestyle changes are an important aspect of managing symptoms. Medications such as antidepressants, sodium oxybate, and pitolisant can help some people have fewer episodes of cataplexy. It is important to consult a healthcare provider for diagnosis and treatment if you experience sudden muscle weakness.