A rare disease that is sudden and a transient episode of loss of muscle tone, which is often triggered by emotions. Only 5 out of every 10,000 people may have this disease, but it also frequently affects people who have narcolepsy, a disorder whose principal signs are EDS (Excessive Daytime Sleepiness), sleep attacks, sleep paralysis, hypnagogic hallucinations and disturbed night-time sleep

Cataplexy is most often confused with epilepsy, where a series of flashes or other symptoms that cause superficially similar seizures. Cataplexy can also be present as a side effect of SSRI Discontinuation Syndrome.

Cataplexy shows itself as muscular weakness which may range from a barely perceptible slackening of the facial muscles to the dropping of the jaw or head, weakness at the knees, or a total collapse. Usually the speech is slurred, your vision is impaired or you have double vision, inability to focus, although hearing and awareness remains normal.

Unlike a lot of other symptoms, these attacks are triggered by strong emotions such as exhilaration, anger, fear, surprise, orgasm, embarrassment, and laughter. Cataplexy may be partial or complete, affecting a range of muscle groups, from those controlling facial features to those controlling the entire body.

Cataplexy is a side affect of narcolepsy. It must be treated differently and separate medication must be taken. A newer drug, venlafaxine; a more recent antidepressant called Xyrem, the brand-name is Hydroxybutyrate GHB with fewer side effects.