Cataplexy is a sudden, short-lived loss of muscle tone triggered by strong emotion, most often laughter, excitement, surprise, anger, or fear. Consciousness is usually preserved.

It can cause:

It is strongly associated with narcolepsy type 1, a neurologic sleep-wake disorder. Episodes typically last seconds to a few minutes and resolve on their own. Unlike a seizure, the person is generally aware of what is happening and does not have post-event confusion. NHLBI overview

What to do: See a sleep-medicine specialist or neurologist, particularly if there is daytime sleepiness, sleep paralysis, vivid dream-like hallucinations when falling asleep or waking, or episodes while driving or working. Diagnosis often includes overnight polysomnography and a multiple sleep latency test. Treatment may include scheduled naps and prescribed medicines such as sodium oxybate or certain antidepressants, selected according to symptoms and safety considerations.

Seek urgent assessment after a collapse if there is injury, loss of awareness, prolonged confusion, chest pain, new neurologic symptoms, or episodes that are not clearly emotion-triggered.

A 2024 systematic review found sodium oxybate effective for adult narcolepsy with cataplexy, but medication decisions need individual specialist supervision (review, PMID 39601985).