Antipsychotic switching: results from a one-year prospective, observational study of patients with schizophrenia

ABSTRACTObjective: The Health Outcomes of a Canadian Community Cohort (HOCCC) study is a 1-year prospective observational study of outpatients with schizophrenia or related psychotic disorders. The purpose of the study was to compare effectiveness of antipsychotic treatment as measured by 1-year treatment completion rates.Design and methods: Patients (N = 929) were enrolled if in the course of usual clinical practice they switched to a second-generation antipsychotic (SGA). Observational data were collected for up to 1 year. The primary analysis compared 1-year treatment-completion rates for the olanzapine cohort with the other SGA cohort (quetiapine, risperidone, clozapine), using a chi-squared test.Results: Of 929 patients enrolled, 64.8% (516/796) of evaluable patients completed 1 year of treatment. There was no statistically significant difference in the proportion of treatment completers between the olanzapine cohort (67.4%, 256/380) and the other SGA cohort (62.5%, 260/416). Treatment-completion rat...