- Also known as ephialtes nocturnus, dream anxiety attack, REM anxiety dream, REM-nightmare, and D-nightmare. The term nightmare comes from the Old English noun *mare, which means hag or goblin (see also the entries Mar, Mare, and Incubus). It is used to denote a terrifying or otherwise disturbing *dream from which the dreamer awakens. The terms D-nightmare and REM-nightmare refer to the temporal coincidence of nightmares with D-sleep, which stands for desynchronized sleep or rapid eye movement (REM) sleep. The first Greek physician known to have dealt with the nightmare in his research was Themison of Laodicea (first century BC), a pupil of Asclepiades of Bythinia (124-c. 40 BC). In ancient Greece the nightmare used to be associated with * Ephialtes, the daimon of nightmares, and allegedly a manifestation of Pan. The mythological creature the Romans associated with the nightmare was the * incubus. In 1830 the Scottish physician Robert MacNish (1802-1837) qualified the nightmare as follows: "Nightmare may be defined [as] a painful dream, accompanied with difficult respiratory action, and a torpor in the powers of volition... The affection, the Ephialtes of the Greeks, and Incubus of the Romans, is one of the most distressing to which human nature is subject. Imagination cannot conceive the horrors it frequently gives rise to, or language describe them in adequate terms. They are a thousand times more frightful than the visions conjured up by necromancy or diablere; and far transcend every thing in history or romance, from the fable of the writhing and asp-encircled Lao-coon to Dante's appalling picture of Ugolino and his famished offspring, or the hidden tortures of the Spanish inquisition. The whole mind, during the paroxysm, is wrought up to a pitch of unutterable despair: a spell is laid upon the faculties, which freezes them into inaction; and the wretched victim feels as if pent alive in his coffin, or overpowered by resistless and immitigable pressure." Laboratory studies indicate that the majority of nightmares occur during stages of REM sleep. Dream-like phenomena resembling nightmares may also occur during stages of nonrapid eye movement (NREM) sleep, but these are believed to differ in a conceptual sense (and possibly in a phenomenological and physiological sense as well) from the nightmare proper. Thus the terms sleep-onset nightmare and *hypnagogic nightmare are used to denote instances of dreamlike * hypnagogic hallucinations occurring during sleep onset, i.e. during stage N1 sleep as recorded on the electroencephalogram. The average 1-year prevalence of nightmares for adults is estimated as lying around 1 or 2. However, under the influence of somatic or psychiatric illness, their incidence may increase significantly. Some therapeutics known for their ability to increase the frequency of nightmares are the alkaloid reserpine, the dopamine precursor L-dopa, and beta blockers. Some therapeutics known for their ability to increase their frequency during withdrawal episodes are the benzodiazepines and the barbiturates. The same holds true for alcohol withdrawal. While stressful and traumatic eventscanalsoleadtoanincreaseintheinci-dence of nightmares, a general sense of safety or protection is believed to reduce them. Because of their occurrence during sleep, nightmares - as well as other dreams - are by definition set apart from * hallucinations proper and *hypnagogia. Conceptually as well as phenomenologically, the nightmare is also distinguished from night terror (also known as stage 4 nightmare, pavor noc-turnus, and incubus attack). The latter terms are used to denote a sudden moment of arousal and awakening from slow-wave sleep (also known as stage 4 sleep, stage N4 sleep, or deep sleep) characterized by marked anxiety, and autonomic symptoms such as profuse perspiration, mydria-sis, tachycardia, and tachypnea. This moment of arousal and awakening is often accompanied by screaming and motor movements. Dream recall or recollection upon awakening is typically poor or absent. What distinguishes night terror from the nightmare is that the nightmare is conceptualized as a dream, whereas night terror is conceptualized as an instant of arousal and awakening. When a nightmare takes on the quality of a long, frightening dream during which a traumatic event is re-experienced exactly or almost exactly, the terms * traumatic nightmare and post-traumatic nightmare apply.ReferencesHartmann, E. (1998). Dreams and nightmares. The new theory on the origin and meaning of dreams. New York, NY: Plenum Trade.MacNish, R. (1854). Philosophy of sleep. Second edition. Hartford: Silas Andrus & Son.Roscher, W.H. (1972). Ephialtes. A pathological-mythological treatise on the nightmare in classical antiquity. In: Pan and the nightmare.Trans-lated by O'Brien, A.V. Edited by Hillman, J. Dallas, TX: Springfield Publications.
Dictionary of Hallucinations. J.D. Blom. 2010.