- The term zoopsia derives from the Greek words zoion (living creature, animal) and opsis (seeing). It is used to denote an *illusion or *complex visual hallucination depicting one or more animals, such as cats, dogs, tigers, elephants, snakes, rodents, or insects. These hallucinated animals may have a realistic appearance, but they can also be cartoonesque in nature or take the form of mythical or fantasy creatures. It has been suggested that the apparent size of the hallucinated animals may be dependent on the point of ocular fixation. As noted by the Swiss physician Ferdinand Morel (1888-1957), a fixation point at 1 m may result in the seeing of mice, at 2 m in the seeing of pigeons, and at 3 m in the seeing of cats and rabbits. Etiologically, zoopsia is associated with a variety of conditions, including * Charles Bonnet syndrome, *peduncular hallucinosis, *delirium, *delirium tremens, * alcoholic hallucinosis, * cocaine hallucinosis, and many other substance-induced hallucinatory syndromes. According to the French psychiatrist Henri Ey (1900-1977), zoopsia can be conceptualized as a typical expression of fear or terror. As noted by him, the visual hallucinations of zoopsia have a certain tendency to develop into * compound hallucinations, notably in combination with olfactory and/or tactile sensations, and less often in combination with verbal auditory ones. A related symptom in which vermin are perceived (tactically and/or visually) as crawling upon or beneath the skin is known as formication or *formicative hallucination.ReferencesEy, H. (2004). Traité des hallucinations. Tome 1. Paris: Claude Tchou pour la Bibliothèque des Introuvables.ffytche, D.H. (2007). Visual hallucinatory syndromes: Past, present, and future. Dialogues in Clinical Neuroscience, 9, 173-189.Morel, F. (1937). Hallucination et champ visuel. De la texture, de la forme, de la multiplicité, des mouvements que présentent les hallucinations visuelles du delirium tremens. Annales Médico-psychologiques, 95, 742-757.
Dictionary of Hallucinations. J.D. Blom. 2010.