Hypnagogic/Hypnopompic Hallucinations

Hypnagogic and hypnopompic hallucinations are perceptions that occur while going to sleep (hypnagogic) and on waking (hypnopompic).

Hypnagogic hallucinations are false perceptions in any modality (usually auditory or visual) that occur as a person goes to sleep; whereas, hypnopompic hallucinations occur as a person awakens.

These hallucinations Opens in new window occur in normal people and are not indicative of psychopathology.

According to Zilboorg and Henry (1941), hypnagogic hallucinations were first mentioned by Aristotle. It is known that the conscious level fluctuates considerably in different stages of sleep Opens in new window, and both types of abnormal perception probably occur in a phase of increasing drowsiness:

the structure of thought, feelings, perceptions and fantasies and, ultimately, self-awareness becomes blurred and merged into oblivion.

These experiences occur in many people in good health. They are also described with narcolepsy, cataplexy and sleep paralysis to form a characteristic tetrad of symptoms.

Toxic states such as glue sniffing, acute fevers (especially in children), postinfective depressive states and phobic anxiety neuroses are other conditions that may be associated.

The perception may be visual Opens in new window, auditory Opens in new window or tactile. It is sudden in occurrence, and the subject believes that it woke him up, for example a loud voice in the street below saying ‘world war!’, a feeling of someone pushing him over the bed or seeing a man coming across the bedroom. The importance of these phenomena in psychopathology is to recognize their nature and realize that they are not necessarily abnormal, even though they may be truly hallucinatory.

    Research data for this literature has been adapted from these following manuals:
  1. Crash Course Psychiatry - E-Book By Katie FM Marwick, Steven Birrell
  2. Core Psychiatry E-Book, Edited by Padraig Wright, Julian Stern, Michael Phelan