This is the name given to a peculiar state in which a person confuses the dream world with the actual world. On being roused from sleep, naturally or artificially, the motor centres awake sufficiently for the individual to perform movements, but the dream continues; the dream has been, often, instigated by the awakening. Persons and objects present are mistaken for dream figures. Many sad effects have resulted from such confusion. Instances are recorded of persons, while in the condition of sleep drunkenness, mistaking others near them for robbers and killing them. The condition is, fortunately, rare, and may be considered as a disorder of the hypnagogic state.

Hammond1 gives many examples, among them the following:

"A gentleman was roused one night by his wife who heard the street door bell ring. He got up without paying attention to what she said, dragged the sheets off the bed, tore them hurriedly into strips and proceeded to tie the pieces together. She finally succeeded in bringing him to himself, when he said that he thought the house on fire and he was providing means for their escape. He did not recollect having had any dream of the kind, but he was under the impression that the idea had occurred to him at the instant of his waking.

"Another was suddenly aroused from a sound sleep by a slamming of a window shutter by the wind. He sprang instantly from his bed and seizing a chair that was near hurled it with all his strength against the window. The noise of the breaking glass awakened him.

1 Op. cit., p. 314.

He explained that he imagined some one was trying to get into the house, and had let his pistol fall on the floor thereby producing the noise which had startled him."

Overfatigue and ill health may predispose to this affection; usually it occurs only in persons who are neurotically unstable. When the condition exists, the individual is potentially dangerous and should sleep in a room by himself. At times some experience of strong emotional tone may be the background for the disorder. However caused, it should receive the attention of a skilled medical psychologist.