From Big Medical Encyclopedia

ILLUSIONS (fr. illusion deception, deceptive representation) — false, wrong perception of objects of a pla of the phenomena real-life at present. As one of types of deception of perception And. were separated from hallucinations (see) in 1817 the fr. psychiatrist Zh. Eskirol. Main difference And. from hallucinations existence is at them in a false manner the perceiving real object. So, e.g., the curtailed dressing gown on a bed is perceived as a figure of the lying person, spots on linen seem insects, in noise of a rain the sound of steps, in a dialect of people on the street — separate words and phrases to the address of this person is heard, taste of food is felt how taste of inedible substance, napr, clays, the smell of bread seems a smell of decay, the touch of a blanket is felt as something wet, cold, similar to a touch of a frog.

Depending on the relation to these or those sense bodys allocate visual, acoustical, flavoring, olfactory, tactile Y. Slukhovye I. which contents are separate words or phrases, call verbal I. Intensivnye and constantly arising verbal And. designate the term "illusory hallucinosis". In this case And. arise against the background of painfully changed affective state, preimushchestveino alarm and fear, and are followed by crazy interpretation.

Proceeding from psikhol, mechanisms of deception of perception, Jaspers (To. Jaspers, 1959) subdivided And. on 3 types: depending on a carelessness, affective and pareydoliya. At And. a carelessness instead of one word another is heard, close on sounding, the stranger is accepted to the acquaintance, etc. Affective And. arise iod influence of affects of fear, alarm. E.g., the timid person, going at night along the desert street, easily takes a shadow from any subject for a figure of the hidden person. Affective And. are especially frequent at painful changes of an emotional state. Pareydoliya represent visual And. fantastic, fantastic contents. They are shown by the fact that during the strengthening of figurative imagination in such real objects as the drawing of wall-paper, a pattern of a carpet, a crack and a spot on walls and a ceiling, the changing exotic landscapes, fortresses, pictures of battles, faces of people, fancy animals, etc. seem.

In an origin And. an important role is played psikhol, features of perception, in particular inherent to the person and are normal incompleteness of perception, lacks in Krom are met by ideas of this object on the basis of former experience. Illusory perception is promoted by changes of concentration of active attention at exhaustion, conditions of alarm, fear and nervousness, the strengthened imagination. And. especially easily arise at children, the Crimea insufficient differentiation of perception, rich imagination, difficulty of differentiation of fiction and reality are inherent. In emergence And. the factors reducing the clearness of perception have a certain value: insufficient illumination of objects, priglushennost of sounds, and also visual impairments and hearing.

In a pathogeny And. the role of gipnoidny conditions of cortical analyzers is supposed.

Incidentally And. can arise also at mentally healthy, however at mental diseases they meet considerably more often, are more various and bright. Are most characteristic And. for conditions of superficial stupefaction, especially a delirium (I eat. A delirious syndrome), at acute intoksikatsionny (e.g., in case of alcoholic delirium tremens), infectious and other symptomatic psychoses. Besides, And. often arise at patients with crazy and affektivno crazy psychoses of various origin. Incidental, unstable And. meet at neurosises and neurosis-like states.

Treatment And. — therapy of a basic disease.

Bibliography: Gilyarovsky V. A. Psychiatry, M. — L., 1938; Ronchevsky S. P. K to the analysis of deception of perception at meekalinovy poisoning, in book: Sov. nevropspkhnat., under the editorship of V. P. Axes fishings, t. 3, page 182, M. — L., 1940; F about t I am a N about in M. I. K a systematics and psychopathology of illusions of sight, in book: Vopr, the general psikhopatol, and social adaptation the loony, patients, under the editorship of A. A. Portnov, page 23, M., 1974, bibliogr.; A h 1 e n-s t i e 1 H. u. K an u f m a n n R. tiber pa-thologische Illusionen, Arch. Psychiat. Nervenkr., Bd 202, S. 592, 1962, Bibliogr.; Jaspers K. Allgemeine Psychopatho-logie, B., 1959; M o u r e n P, e t T a t o s-si is scarlet A. Les illusions visuo-spatiales, Encephale, t. 52, p. 439, 1963, bibliogr.

B. B. Kovalyov.