Does the positive/negative symptomatological distinction account for the severe neuropsychological impairment in schizophrenia?
Date
1991
Authors
Jonsdottir, Thuridur Johanna.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
To examine neuropsychological functioning and clinical symptom patterns, 50 medicated male and female schizophrenic patients, 25 Canadian and 25 Icelandic, and 14 matched normal controls were given a thorough neuropsychological assessment. The patients were rated on Andreasen's Scales for the Assessment of Positive and Negative Symptoms. While defective performance on practically all tests of general cognitive, verbal and non-verbal memory, and cognitive frontal lobe activities differentiated the schizophrenics from the normal controls, the spectrum of impairment was neither accounted for by Andreasen's clinical subgrouping nor by mathematical subgrouping of the global summary scores. Significant correlations, however, were found between functions of double conceptual tracking, which are sensitive to diffuse brain damage, and the negative symptoms summary score. One negative symptom, Affective Flattening, showed a consistent negative correlation with several tests of general cognitive abilities, some of which rely upon response speed. No correlations were found between the severe memory deficits and frontal lobe dysfunction manifested by the patients and the positive/negative symptomatology indicating that a dimension other than symptomatology must account for these severe cognitive deficits. The majority of findings supported the theory of bilateral impairment in schizophrenia although defective performance of fine motor movement of the dominant hand might indicate a left deficit and also support theories of the Psychotic Motor Syndrome. Medical history variables indicated that although length of hospital stay and the dose of neuroleptic medication are closely linked with symptomatology, the number of acute admissions has a stronger association with generalized cognitive dysfunction and mental confusion.
Although Andreasen's distinction of positive/negative symptoms appears to be a valid construct, it may be potentially misleading as the majority of medicated schizophrenics present with a mixture of positive and negative symptoms. On the basis of correlational and factor analyses of symptoms, it was therefore suggested that a trichotomous distinction of symptoms might represent a more valid construct.
Thesis (Ph.D.)--Dalhousie University (Canada), 1991.
Although Andreasen's distinction of positive/negative symptoms appears to be a valid construct, it may be potentially misleading as the majority of medicated schizophrenics present with a mixture of positive and negative symptoms. On the basis of correlational and factor analyses of symptoms, it was therefore suggested that a trichotomous distinction of symptoms might represent a more valid construct.
Thesis (Ph.D.)--Dalhousie University (Canada), 1991.
Keywords
Biology, Neuroscience., Psychology, Psychobiology.