Differential effects of olanzapine and risperidone on cognition in schizophrenia? A saccadic eye movement study.

Recent studies suggest that novel antipsychotics have positive effects on certain cognitive functions in schizophrenia. The present study investigated this claim by means of saccadic paradigms, which provide a selective index of cognitive function. Thirty-three first-episode schizophrenic patients were randomly assigned to either olanzapine or risperidone treatment and compared with healthy control subjects for three saccadic paradigms. The influence of symptom profile, extrapyramidal symptoms, age, education, gender, hospitalization, and medication dose on cognitive performance was also investigated. Although the two patient groups did not differ from each other in task performance, both patient groups showed substantial problems in inhibitory control of saccades. A high level of education appeared to be protective for this impairment.