Medication Replacing Conventional with Atypical Antipsychotic : Effect on Cognitive Function in Schizophrenic Patients

Abstract

: We studied whether or not replacing conventional antipsychotic medications with newer atypical antipsychotics has a favorable effect on cognitive function in schizophrenia. Twenty patients with schizophrenia who had been treated with conventional antipsychotics were switched randomly to either of two atypical antipsychotic agents, risperidone or perospirone. Clinical and neuropsychological evaluations were performed before and approximately four weeks after completing medication change. Patients required a lower dose of antiparkinsonian drugs and presented fewer parkinsonian symptoms while taking atypical antipsychotics compared with conventional antipsychotics. In addition, patients taking perospirone required smaller antiparkinsonian drug dose than those taking risperidone, suggesting that perospirone caused fewer extrapyramidal adverse effects. Perospirone roughly paralleled risperidone in diminishing psychotic symptoms but these were fewer and the subjectively assessed quality of life was better in patients treated with risperidone. Improvement in neuropsychological test results upon switching to atypical agents was remarkable for verbal memory and various measures of frontal/executive functions. The effect of risperidone and perospirone on frontal/executive functions appeared equivalent while changing to risperidone rather than perospirone achieved greater improvement in verbal memory. Differences in verbal memory favoring risperidone may reflect a favorable balance between D2 dopamine and 5HT2A serotonin receptor blockade. Further study is needed concerning how this cognitive improvement might be related to improved social functioning.