Evaluation of antipsychotic and concomitant medication use patterns in patients with schizophrenia.

Abstract

To describe antipsychotic medication use patterns in an inner-city, outpatient population of indigent patients with schizophrenia. This retrospective cohort study used the Regenstrief Medical Record System to identify schizophrenic patients receiving antipsychotic medication(s). Patients were included and identified as initiating a new treatment episode if they did not receive any antipsychotic prescription for 90 days before their first antipsychotic prescription in 1995. Each patient was followed for 1 year. Three hundred and sixteen patients met study criteria. Typical and atypical (clozapine and risperidone) antipsychotic agents were selected as initial therapy in 88% and 12% patients, respectively. The majority of patients (71.5%) were exposed to only one antipsychotic agent during their treatment year. Approximately 25% of all patients switched from one antipsychotic to a different antipsychotic during 12 months of therapy. Nearly 90% of patients augmented their prescribed antipsychotic with a concomitant medication during the 12-month study period. Approximately 30% of the cohort received treatment with an antipsychotic for 12 continuous months and were, thus, classified as having stable antipsychotic therapy. The majority of patients (67.1%) had periods of interrupted therapy (range, 1-11 months) during the 12 month study period. As of 1995 an overwhelming majority of schizophrenic patients in this indigent, inner-city population initiated therapy with a typical antipsychotic. Patients frequently switched antipsychotics and discontinued their therapy during the 1 year study period. Reasons for switching or discontinuing may include the following: ineffective therapy; patient intolerance; change in symptoms; and improved assessment and understanding of the diagnosis or physician preference.