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A cognitive neuropsychological approach to the study of delusions in late‐onset schizophrenia
Author(s) -
Phillips Mary L.,
Howard Robert,
David Anthony S.
Publication year - 1997
Publication title -
international journal of geriatric psychiatry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 129
eISSN - 1099-1166
pISSN - 0885-6230
DOI - 10.1002/(sici)1099-1166(199709)12:9<892::aid-gps657>3.0.co;2-0
Subject(s) - delusion , psychology , schizophrenia (object oriented programming) , neuropsychology , cognition , psychiatry , psychosis , neuropsychological test , perception , audiology , clinical psychology , medicine , neuroscience
Abstract Objective . Hypotheses to explain delusion formation include distorted perceptual processing of meaningful stimuli (eg faces), abnormal reasoning, or a combination of both. The study investigated these hypotheses using standardized neuropsychological tests. Design . A three‐patient case‐study, compared with a small group ( n = 8) of age‐matched normal control subjects. Setting . Hospital in‐ and outpatients. Age‐matched normal controls were from local residential homes. Patients . Three subjects with late‐onset schizophrenia, two currently deluded and one in remission. Both deluded subjects had persecutory beliefs. One had a delusion of misidentification. Interventions . All subjects were administered standardized neuropsychological tests of facial processing and tests of verbal reasoning. Main outcome measures . The test scores of the three patients were compared with published normal values and the age‐matched control data. Results . The tests demonstrated impaired matching of unfamiliar faces in deluded subjects, particularly in the subject with delusional misidentification. Increasing the emotional content of logical reasoning problems had a significant effect on the deluded subjects' reasoning but not that of the normal controls. Conclusion . The findings suggest impaired visual processing plus abnormal reasoning in deluded subjects. However, these impairments are relatively subtle given the severity of psychiatric disorder in the patients studied. © 1997 John Wiley & Sons, Ltd.