REM sleep disorder, sleepwalking, narcolepsy. These and other sleep disorders are studied every night. They are suffered much more often. A man asleep can murder his wife. A woman dreaming can beat her husband senseless.

You can drive a car across town and wake up in a stranger's house. I might not remember ever sleeping when I wake in my chair at work.

Cataplexy is a strange neurologic situation, which is sometimes confused with epilepsy. Cataplexy often affects people who have narcolepsy, a disorder in which there is great difficulty remaining awake during the daytime. The word cataplexy means, "to strike down." It happens in narcolepsy patients who describe it as sudden attacks of muscle weakness. It usually affects both sides of the body. It often happens because of strong emotions.

Cataplexy may be most severe when the subject is tired rather than completely alert and can lead to considerable anxiety although anxiety itself is not a trigger. The attacks last some minutes and may end in continuation of normal behavior or the sufferer may slip into sleep sometimes of extended duration.