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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An experiment is described in which deluded subjects with a diagnosis of schizophrenia or of delusional disorder (paranoia) were compared with a nondeluded psychiatric control group and a normal control group on a probabilistic inference task. Factors relevant to belief formation and maintenance were investigated. Deluded subjects requested less information before reaching a decision and were more ready to change their estimates of the likelihood of an event when confronted with potentially disconfirmatory information. No differences were found between the two diagnostic groups of deluded subjects. The results are discussed in light of prevailing theories of the importance of abnormal experience rather than reasoning biases in the formation and maintenance of delusional beliefs. It is suggested that a reasoning abnormality is involved, which may coexist with perceptual abnormalities.
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PMID:Reasoning in deluded schizophrenic and paranoid patients. Biases in performance on a probabilistic inference task. 200 89

This study examined visuo-cognitive processing of threat-related (anger, fear) and non-threat faces (happy, sad, neutral) in deluded schizophrenia (n=11), non-deluded schizophrenia (n=8), and healthy control (n=22) participants. Focal analyses examined scanpath aberrations for particular facial expressions in sub-groups of schizophrenia patients determined by the presence or absence of overt delusions. Deluded schizophrenia subjects exhibited significantly fewer fixations of shorter duration for all faces, and fewer fixations of reduced duration to the feature areas of negative facial expressions (anger, sad), compared with healthy controls. Compared with non-deluded schizophrenia subjects, deluded subjects exhibited fewer fixations to fear expressions and more fixations to the feature areas of happy expressions. These findings were revealed in the context of restricted scanning (reduced number and duration of fixations, shorter scanpath length and shorter duration of fixations to facial features) in the entire schizophrenia group (n=19) compared with healthy controls. The findings suggest a controlled attentional bias away from the feature areas of negative facial expressions in deluded schizophrenia, that is, specific to threat-related expressions compared with non-deluded schizophrenia subjects. This controlled bias away from negative social stimuli in deluded schizophrenia is discussed in terms of an attentional style of 'vigilance-avoidance' operating across early and late stages of information processing.
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PMID:Visual scanpaths to threat-related faces in deluded schizophrenia. 1291 98

Deluded people differ from nondeluded controls on attributional style questionnaires and probabilistic-reasoning and theory-of-mind (ToM) tasks. No study to date has examined the relations between these 3 reasoning anomalies in the same individuals so as to evaluate their functional independence and potentially inform theories of delusion formation. We did so in 35 schizophrenic patients with a history of delusions, 30 of whom were currently deluded, and 34 healthy controls. Compared with healthy controls, patients showed (a) a jumping-to-conclusions bias and a bias to overadjust when confronted with a change of evidence on probabilistic-reasoning tasks, (b) an excessive externalizing attributional bias, and (c) performance deficits on 3 ToM tasks. Probabilistic-reasoning and ToM measures correlated, while attributional-bias scores were independent of other task measures. A general proneness to delusional ideation correlated with probabilistic-reasoning and ToM measures, while externalizing bias was unrelated to the study measures of delusional ideation. Personalizing bias associated specifically with paranoia across the clinical and nonclinical participants. Findings are consistent with a common underlying mechanism in schizophrenia which contributes to the anomalies on probabilistic-reasoning and ToM tasks associated with delusions. We speculate that this mechanism is impairment of the normal capacity to inhibit "perceived reality" (the evidence of our senses), a capacity that evolved as part of the "social brain" to facilitate intersubjective communication within a shared reality.
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PMID:Reasoning anomalies associated with delusions in schizophrenia. 1862 10