A comparison of two novel antipsychotics in first episode non-affective psychosis: one-year outcome on symptoms, motor side effects and cognition

Abstract

The main objective of this study was to compare 1-year outcome on symptoms, extrapyramidal side effects (EPS) , positive and negative symptoms, and domains of cognition in first episode psychosis (FEP) patients. Drug-naive FEP patients, who were similar on a number of characteristics likely to affect outcome, were treated with only one antipsychotic (risperidone or olanzapine) for at least 1 year and compared at baseline and after 1 year of treatment. Differences in outcome were assessed using an analysis of co-variance with change scores between initial assessment and after 1 year of treatment on levels of psychotic, disorganization and psychomotor poverty symptoms, EPS (parkinsonism, akathesia and dyskineisa) and domains of cognition as the dependent variable, respective baseline scores as covariates, and drug group as the independent variable. While patients in both groups showed substantial improvement, there were no significant differences in the magnitude of change in reality distortion, disorganization and psychomotor poverty symptoms. Trends in change in EPS favouring olanzapine and on some domains of cognition (processing speed and executive functions) favouring risperidone failed to reach statistical significance. The failure to confirm previous claims of greater improvement on either risperidone or olanzapine in patients with a first episode of psychosis may be the result of methodological bias introduced by unequal dosing between the two drugs or the use of chronically ill and treatment-refractory patients in previous studies.