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false belief based upon a misinterpretation of reality. It is not, like a hallucination, a false sensory perception, or like an illusion, a distorted perception. Delusions vary in intensity, and are not uncommon among substance abusers, particularly those who use amphetamines, cocaine, and hallucinogens. They also occur frequently among individuals who have been diagnosed with Alzheimer's diseaseAlzheimer's disease
, degenerative disease of nerve cells in the cerebral cortex that leads to atrophy of the brain and senile dementia and, ultimately, death. The disease is characterized by abnormal accumulation of plaques and by neurofibrillary tangles (malformed nerve
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, Huntington's diseaseHuntington's disease,
hereditary, acute disturbance of the central nervous system usually beginning in middle age and characterized by involuntary muscular movements and progressive intellectual deterioration; formerly called Huntington's chorea.
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, or schizophreniaschizophrenia
, group of severe mental disorders characterized by reality distortions resulting in unusual thought patterns and behaviors. Because there is often little or no logical relationship between the thoughts and feelings of a person with schizophrenia, the disorder has
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, and during the manic stage of bipolar disorder (see depressiondepression,
in psychiatry, a symptom of mood disorder characterized by intense feelings of loss, sadness, hopelessness, failure, and rejection. The two major types of mood disorder are unipolar disorder, also called major depression, and bipolar disorder, whose sufferers are
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). Some common delusions include persecutory delusions, in which the individual falsely believes that others are plotting against him; delusions of thought broadcasting, where the individual believes his thoughts can be transmitted to others; delusions of thought insertion, in which the individual believes that thoughts are being implanted in his mind; and delusions of grandeur, in which the individual imagines himself an unappreciated person of great importance.
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A conviction based on faulty perceptions, feelings, and thinking.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


Borkman, John Gabriel
suffers from delusions of power. [Nor. Lit.: John Gabriel Borkman]
Bowles, Sally
night-club entertainer thinks she has the makings of a great film actress. [Br. Lit.: Isherwood Berlin Stories in Drabble, 498]
Clamence, Jean-Baptiste
living with his own good and evil. [Fr. Lit.: The Fall]
Dubois, Blanche
felt she and Mitch were above others. [Am. Lit.: A Streetcar Named Desire]
Jones, Brutus
self-styled island emperor experiences traumatic visions. [Am. Lit.: Emperor Jones]
Lockit, Lucy
steals jailer-father’s keys to free phony husband. [Br. Lit.: The Beggar’s Opera]
Pan, Peter
little boy, refuses to grow up; resides in Never Never Land. [Children’s Lit.: Peter Pan]
opium of the people
Marx’s classic metaphor for religion. [Ger. Hist.: Critique of Hegel’s “Philosophy of Right”]
hides head, thinking itself concealed. [Animal Symbolism: Brewer Dictionary, 788]
Allusions—Cultural, Literary, Biblical, and Historical: A Thematic Dictionary. Copyright 2008 The Gale Group, Inc. All rights reserved.


Psychiatry a belief held in the face of evidence to the contrary, that is resistant to all reason
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Delusions had taken on a life of their own, and were paying rich dividends both in terms of votes and ratings.
The conviction expressed in the delusion of control is contrary to common sense.
Belgium also showed the highest delusion rate under the category at 62 percent.
Delusions are among the most common neuropsychiatric features in patients with dementia, especially in those with DLB.
Did Laughead, Martin, and their followers have delusions? Their beliefs were certainly bizarre and firm.
There are good reasons to think that, at least, the elimination of the special treatment of delusions is not the best way to deal with the lack of discriminability of Schneiderian symptoms.
The patient's mother experienced auditory hallucinations and paranoid delusions. She likely had schizophrenia but was never diagnosed formally nor treated.
From behavioural disorganization to magic rituals and catatonia regards the behavioural psychopathology that gravitates around delusion, emerged as a consequence of its contents.
However, delusions, by definition, are "fixed false beliefs." Challenging a patient regarding their delusions is likely pointless, as the patients' minds cannot be changed.
His thinking showed delusional perception, sudden delusional idea, delusion of persecution and reference.
Initially, Cotard formulated that the condition would be a new kind of depression characterized by anxious melancholy, condemnation of ideas, insensitivity to pain, negation delusion of the organs, and immortality delusion.
(31) The question would then--and only then--become whether he nevertheless suffered from an insane delusion. (32) In Hargrove's Will, the appellate court reversed the jury's verdict that "the testator suffered from an insane delusion that two children born to his wife during their marriage were not his" given that Hargrove exhibited no mental deficiencies and there existed some rational explanation for his delusion about his children's paternity.