Differential benefits of olanzapine on executive function in schizophrenia patients: Preliminary findings

Schizophrenia patients show executive function (EF) impairments in voluntary orienting as measured by eye-movements. We tested 14 inpatients to investigate the effects of the antipsychotic olanzapine on EF, as measured by antisaccade eye-movement performance.

Patients were tested at baseline (before olanzapine), 3-5 days post-medication, and 12-14 days post-medication. Patients were also assessed on the Positive and Negative Syndrome Scale (PANSS) to measure the severity of schizophrenia-related symptoms, and administered the Stroop task, a test of EF. Nine matched controls were also tested on the antisaccade and Stroop.

Both groups showed improvement on Stroop and antisaccade; however, the schizophrenia group improved significantly more on antisaccade, indicating an additional benefit of olanzapine on EF performance. Patients with poorer baseline antisaccade performance (High-Deficit) showed significantly greater improvement on the antisaccade task than patients with better baseline performance (Low-Deficit), suggesting that baseline EF impairment predicts the magnitude of cognitive improvement with olanzapine. These subgroups showed significant and equivalent improvement on PANSS scores, indicating that improvement on the antisaccade task with olanzapine was not a result of differences in magnitude of clinical improvement.

This preliminary study provides evidence that olanzapine may be most advantageous for patients with greater baseline EF deficits.