A preliminary study of the comparative effects of olanzapine and fluphenazine on cognition in schizophrenic patients

Abstract

The aim of the study was to compare the effect of olanzapine versus fluphenazine treatment on cognitive functioning. Eighteen schizophrenic outpatients, aged 25 - 61 (average 37 years), all meeting DSM-IV diagnostic criteria for schizophrenia, were included in the study. They were randomly assigned to 22 weeks of either olanzapine or fluphenazine treatment. Certain subscales of the Wechsler Adult Intelligence Scale, the Stroop Neuropsychological Screening Test and the Wisconsin Card Sorting Test were performed. Olanzapine treatment proved to have a beneficial effect on digit-symbol performance and some aspects of executive function. In comparison to the fluphenazine treatment, the olanzapine treatment only showed a beneficial effect in increased percentage of conceptual level responses. Although the results are preliminary, they could implicate that the benefit of olanzapine treatment is primarily related to certain aspects of executive function, i.e. frontal lobe functioning. Copyright 2000 John Wiley & Sons, Ltd.