INDIVIDUAL-DIFFERENCES IN COGNITIVE DECLINE IN SCHIZOPHRENIA

The authors' goal was to determine whether cognitively impaired patien ts with schizophrenia exhibit age-related cognitive declines similar t o those of patients with schizophrenia who do not have substantial cog nitive impairment. Method: Correlation coefficients were computed betw een age and the Average impairment Rating, a summary index of cognitiv e ability, in a group of 77 patients with schizophrenia. These patient s were clustered into two groups: one with near-normal cognitive funct ion (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 grou ps. Results: There were significant correlations between age and the A verage Impairment Rating in all groups except the cognitively impaired patients with schizophrenia, in which a zero-order correlation was ob tained. Conclusions: Patients with schizophrenia who have substantial cognitive impairment do not have the significant correlation between a ge and cognitive function found in patients with schizophrenia who hav e mildly impaired or normal cognitive abilities, suggesting earlier on set of cognitive deficit in the cognitively impaired patients with sch izophrenia.