Effects of olanzapine, quetiapine, and risperidone on neurocognitive function in early psychosis: a randomized, double-blind 52-week comparison.

The authors sought to compare the effects of olanzapine, quetiapine, and risperidone on neurocognitive function in patients with early psychosis. In a 52-week double-blind, multicenter study, 400 patients early in the course of psychotic illness (<5 years) were randomly assigned to treatment with olanzapine (2.5-20 mg/day), quetiapine (100-800 mg/day), or risperidone (0.5-4 mg/day). The mean modal daily dose was 11.7 mg (SD=5.3) for olanzapine, 506 mg (SD=215) for quetiapine, and 2.4 mg (SD=1.0) for risperidone. A total of 224 patients completed neurocognitive assessments at baseline and at 12 weeks, and 81 patients also completed them at 52 weeks. Neurocognitive composite scores were calculated from the neurocognitive battery used in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) and from the Brief Assessment of Cognition in Schizophrenia. At week 12, there was significant improvement in neurocognition for each treatment (p<0.01), but no significant overall difference between treatments. Composite z score improvements on the CATIE neurocognitive battery were 0.17 for olanzapine, 0.33 for quetiapine, and 0.32 for risperidone. Composite z score improvements on the Brief Assessment of Cognition in Schizophrenia were 0.19 for olanzapine, 0.34 for quetiapine, and 0.22 for risperidone. Statistically significant relationships between improvements in neurocognition and functional outcome were observed at weeks 12 and 52. Olanzapine, quetiapine, and risperidone all produced significant improvements in neurocognition in early-psychosis patients. Although cognitive improvements were modest, their clinical importance was suggested by relationships with improvements in functional outcome.