Short term neurocognitive effects of treatment with ziprasidone and olanzapine in recent onset schizophrenia

Abstract

Background: Cognitive deficits are a core feature in schizophrenia. Cognitive deficits appear to be present at the onset of schizophrenia and persist after remission of psychotic symptoms. As cognitive deficits are associated with poor functional outcome, they form an important focus of treatment. There are relatively few head-to-head comparisons of the effects of second generation antipsychotics on cognition in recent onset schizophrenia. This is the first study to compare the effects of a short term treatment of olanzapine versus ziprasidone on cognitive functioning in recent onset schizophrenia. An earlier study conducted in chronic patients revealed an enhancement of cognition after treatment for both agents, but the extent of improvement was not significantly different between ziprasidone and olanzapine.

Method: Patients with recent onset schizophrenia with limited previous exposure to medical treatment underwent a double blind randomized controlled treatment trial. Fifty-six patients completed the neuropsychological testing procedure prior to randomization and after eight weeks of treatment and were included in the analysis. We tested cognitive functioning in general and verbal memory in particular. We calculated a single unweighted composite score based on nine cognitive tests to determine general cognitive functioning.

Results: Cognition appeared enhanced after treatment, but was not significantly different between treatment groups, neither for the verbal memory measures, nor for the neurocognitive composite score. Furthermore, cognitive enhancement did not correlate to clinical improvement.

Conclusion: Cognitive deficits are not a reason for preferentially prescribing one of the two second generation antipsychotics tested over the other.