sleep deprivation-induced hallucination

   Also known as sleep deprivation hallucination. The term sleep deprivation refers to the deliberate prevention of sleep. Sleep deprivation may be self-induced or induced by others, as in interrogation, torture, or sleep deprivation experiments. On the basis of sleep deprivation experiments it is known that many individuals can do without sleep for a period of up to 60 h without any substantial effects upon their performance on tasks with a novel or challenging character, whereas their performance on familiar and especially boring tasks tends to decrease dramatically. After 30-60 h of sleep deprivation, overall performance tends to decrease and symptoms such as dysarthria, blurring of vision, * diplopia, and the occurrence of *microsleeps may become manifest. Microsleeps are defined as short lapses of time, on the order of a few seconds to a minute, during which the brain enters a sleep state and the amplitude of alpha waves on the electroencephalogram (EEG), characteristic of the waking state, tends to be lower. After six or more days without sleep, additional symptoms tend to arise such as drowsiness, disorientation in time and place, illusory alterations in the passage of time (i.e. *time distortions), diminished reality monitoring, derealisation, depersonalization, formal thought disorder, a decrease in motor activity, paranoia, delusions, * illusions (including the *hat illusion), * hypnagogic and * hypnopompic hallucinations, * hallucinations proper, * metamorphopsias (such as * micropsia, * macropsia, * pelopsia, *macroproxiopia, and * microtelepsia), and other *misperceptions. Sleep deprivation-induced hallucinations tend to be visual in nature, but they can also be auditory, tactile, or compound in nature (such as the combined seeing and feeling of cobwebs all over one's body). Pathophysiologically, they are conceptualized as *perceptual release phenomena. As a technique, sleep deprivation may be regarded as diametrically opposed to * sensory deprivation. A person intentionally employing sleep deprivation for the purpose of exploring the psyche may be called a *psychonaut.

   References

   Williams, H.L., Morris, G.O., Lubin, A. (1962). Illusions, hallucinations and sleep loss. In: Hallucinations. Edited by West, L.J. New York, NY: Grune & Stratton.