Individual differences in cognitive decline in schizophrenia.
OBJECTIVE
The authors' goal was to determine whether cognitively impaired patients with schizophrenia exhibit age-related cognitive declines similar to those of patients with schizophrenia who do not have substantial cognitive impairment.


METHODS
Correlation coefficients were computed between age and the Average Impairment Rating, a summary index of cognitive ability, in a group of 77 patients with schizophrenia. These patients were clustered into two groups: one with near-normal cognitive function (N=51) and one with severely impaired cognitive function (N=26). A group of patients with senile dementia (N=21) and another comparison group of nonschizophrenic patients (N=299) were used as reference groups.


RESULTS
There were significant correlations between age and the Average Impairment Rating in all groups except the cognitively impaired patients with schizophrenia, in which a zero-order correlation was obtained.


CONCLUSIONS
Patients with schizophrenia who have substantial cognitive impairment do not have the significant correlation between age and cognitive function found in patients with schizophrenia who have mildly impaired or normal cognitive abilities, suggesting earlier onset of cognitive deficit in the cognitively impaired patients with schizophrenia.
VA Pittsburgh Healthcare System, Highland Drive Division, PA 15206-1287, USA.
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Goldstein
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Allen
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van Kammen
D000328:Adult; D000367:Age Factors; D016000:Cluster Analysis; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology; D003704:Dementia / Q000175:diagnosis / Q000523:psychology; D004522:Educational Status; D006801:Humans; D007206:Individuality; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D014888:Wechsler Scales