Dreadful and violent vision during sleep;nightmare: Oneirodynia involves troubled sleep, nightmares, and and perhaps sleepwalking.

One of the four great divisions of insanity was recognized by William Cullen (1710-1790), a Scottish physician who emphasized the endogenous nature of mental disorders and their relationship to irritability of the nervous system.

The four divisions of insanity include amentia, melancholia, mania, and oneirodynia (somnambulism and nightmare).

Sleepwalking, rising out of bed and walking about during an apparent state of sleep, usually occurring in the first third of the night and lasting a few minutes to a half hour.

A condition during sleep which is usually caused by improper eating or by digestive or nervous troubles, and characterized by a sense of extreme uneasiness or discomfort (as of weight on the chest or stomach, impossibility of motion or speech, etc), or by frightful or oppressive dreams, from which a person wakes after extreme anxiety, in a troubled state of mind.