Factors related to different reasons for antipsychotic drug discontinuation in the treatment of schizophrenia: a naturalistic 18-month follow-up study.

In recent years, measurement of the effectiveness of antipsychotic therapy in schizophrenia has received increasing attention from clinicians and researchers. Several studies have used time to antipsychotic discontinuation for any reason as a global index of antipsychotic effectiveness because it reflects both the physician's and patient's judgment of drug efficacy and tolerability. In this study, we extend this approach by analyzing the rate of discontinuation for different reasons of antipsychotics administered to patients with schizophrenia in a naturalistic setting of care, and explore the determinants of such discontinuation. Ninety-nine patients with schizophrenia who received a first or second generation antipsychotic were followed for 18 months in the Italian outpatient community psychiatric system. We found discontinuation rates for different reasons to be variable and to be influenced by several factors not involving the type of pharmacologic therapy. Some of these factors, such as the frequency of visits to the care unit, underline the need to take into account the role of the care delivery system as potentially influencing the effectiveness of antipsychotics in the "real world".