Background: Cognitive, social, and affective impairments are major features of schizophrenia, despite not being represented in the formal diagnostic criteria. These impairments are associated with major reductions in quality of life for patients with schizophrenia. Treatment with newer antipsychotic medications has been reported to improve all of these areas of functioning, but most studies have not examined the direct association between changes in cognitive functioning and other aspects of the illness.
Objectives: The goal of this analysis was to examine relationships between cognitive and affective symptoms and their impact on social impairments in patients switched to ziprasidone treatment.
Methods: In this study, which is a re-analysis of previously published data, 270 patients were switched from previous treatment with conventional antipsychotics, risperidone, or olanzapine to treatment with ziprasidone. Patients were tested with a cognitive assessment battery, rated with the Positive and Negative Syndrome Scale (PANSS), and received other assessments of safety and tolerability. PANSS scores were divided into factors based on previously published factor analyses, with a focus on the cognitive, prosocial, and anxiety-depression factors.
Results: Statistically significant improvements for global cognitive functioning and the three PANSS subscales were found across the studies. When the data were pooled for a path analysis, changes in cognitive functioning indexed by the PANSS cognitive subscales was the primary predictor of improvements in PANSS prosocial functions, with changes in anxiety-depression accounting for much less variance.
Conclusion: These results suggest a direct relationship between improvements in cognitive and prosocial functioning in patients with schizophrenia and indicate that treatments that enhance cognitive functioning, such novel antipsychotics, have the potential to improve aspects of outcome in schizophrenia even in short-term treatment studies. This issue should be addressed in future double-blind studies of the effects of atypical medications in schizophrenia.