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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 ?
Nasrallah and his coauthors gave 34 mg/day of pimavanserin to 10 patients, aged 21-77 years, with schizophrenia or schizoaffective disorder and refractory hallucinations and delusions. The subjects, all of whom live in a residential group home, had either failed clozapine (n = 6) or failed several antipsychotics but had not yet received clozapine (n = 4).
So, what can be done for patients with refractory hallucinations and delusions who are among the 60% who fail to respond to clozapine, or who experience intolerable adverse effects or safety problems, or who refuse to take clozapine and have their blood drawn every week?
The felling of two Indian planes and the capture of one pilot was not enough damage to overturn decades of delusions; but it was enough to puncture the bubble.
He had had an annual acute episode with persecutory delusions and auditory hallucinations, which disappeared with pharmacological treatment.
Until now, treatments for trauma in psychosis have focused on post-traumatic stress disorder rather than specific symptoms such as hallucinations and delusions.
(5) Neuropsychiatric symptoms in the 12-item version of the Neuropsychiatric Inventory (NPI) including delusions, hallucinations, agitation, depression, anxiety, euphoria, apathy, disinhibition, irritation, aberrant motor behavior, night behavior, and eat/ appetite behavior on the basis of observations within the past month [25]
This seems at odds with predictive coding models of psychopathology and in particular psychotic symptoms like hallucinations and delusions (Corlett et al.
(3) The submissive father accepted the patient's delusions rather than risk jeopardising their relationship.
For cases of primary delusional infestation, the goal generally is to decrease the patient's preoccupation with the delusion and to improve social and occupational functions.
Specific conditions for the development of content of delusions of persecution existed in India during that time.
Othello syndrome occurs most frequently with neurological disorders, and the delusions appear to be associated with dysfunction of the frontal lobes, especially in the right frontal lobe where lesions have been reported more frequently than in the left.
About 40% of those patients have Parkinson's disease psychosis, which is characterized by hallucinations and delusions, significantly burdens caregivers, and often leads to nursing home placement for Parkinson's patients.