Initiation of atypical antipsychotic agents and health outcomes in patients with schizophrenia

Background: Although pharmacological treatments are available for patients with schizophrenia, there is a lack of systematic and comprehensive evaluation of health outcomes following the initiation of atypical antipsychotic agents. Objective: To assess the effects of the initiation of olanzapine or risperidone, the two most widely prescribed atypical antipsychotics, on patients' health outcomes, as measured by changes in patient clinical characteristics between 6 months prior to and post-initiation. Method: We identified patients with schizophrenia by >1 inpatient or greater than or equal to2 outpatient ICD-9-CM codes (greater than or equal to7 days apart) between 1 July 1998 and 30 June 1999, and those who were initiated on olanzepine or risperidone during the period 1 April 1999 to 31 March 2000 inclusive. We then subdivided these patients into three groups: (i) those who were not on olanzapine or risperidone, (ii) those who were not on any atypical agents, and (iii) those who were not on any antipsychotic agents, for 6 months prior to being issued with the new prescription. Using test of means or chi-square tests, we examined whether the initiation of olanzapine or risperidone is related to different changes in patient clinical indicators, such as number of drugs for psychiatric conditions, use of psychiatric services, and use of non-psychiatric services. Results: Between pre- and post-initiation, olanzapine initiators had a greater decrease in the number of psychiatric hospitalizations and use of psychotropic agents, whereas risperidone initiators had a greater reduction in the number of non-psychiatric hospitalizations. The initiation of olanzapine and risperidone appear to be associated with different patient health outcomes. Compared with olanzapine initiators, risperidone initiators had a greater increase in the use of treatments related to mental health, but had greater decrease in the use of treatments related to physical health. Conclusion: Despite olanzapine and risperidone being often perceived as similar antipsychotic agents, our results suggest that the clinical outcomes associated with their use are different. Outcome data from routine clinical practice are required to provide a more comprehensive assessment of these drugs.