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visual hallucination

visual perception in the absence of any external stimulus. Visual hallucinations may be unformed (e.g., shapes, colors) or complex (e.g., figures, faces, scenes). In hallucination associated with psychoses (e.g., paranoid schizophrenia, alcohol- or hallucinogen-induced psychotic disorder), the individual is unaware of the unreality of the perception, whereas insight is retained in other conditions (e.g., pathological states of the visual system). Visual hallucinations may arise in association with lesions of the peripheral or central visual pathway or visual cortical areas; they are often present in temporal-lobe epilepsy and may appear during prolonged isolation. See also peduncular hallucinosis.

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Psychology term of the day

June 19th 2024



n. in infants, lack of psychomotor response or failure to gain weight or produce purposeful behavior, often thought to be a response to separation from mothers and subsequent institutionalization. See also reactive attachment disorder.