SA16. Why do Individuals With Schizophrenia Drop Out From Naturalistic Clinical TRIALS?

Abstract

Background: Randomized controlled trials (RCTs) and observational studies frequently differ with regard to study dropouts. The present naturalistic follow-up investigation aimed to shed a light on this issue by evaluating the time to and the reasons for study dropout in patients suffering from schizophrenia who started monotherapy with an oral new-generation antipsychotic. Method(s): From October 1997 to September 2010, patients aged between 18 and 65 years who were treated in an in-or outpatient unit of the Department of Psychiatry, Psychotherapy and Psychosomatics of the Medical University Innsbruck were allocated to a naturalistic drug monitoring program when starting monotherapy with an oral new-generation antipsychotic except for clozapine. Patients were followed up to a maximum observation period of 12 months, and psychopathological symptoms as well as safety data were assessed regularly. The reasons for study dropout were collected using a clinical report form and were categorized into "poor response," "noncom-pliance," "side effects," "suicide," "withdrawal of written consent," "logistic reasons" (i.e., relocation or continuing treatment at another facility), and "nonappearance." Results: To this end, 194 patients were enrolled in this trial. In all, 9.3% of study participants completed the study. The mean time to study dropout was 2.6 +/- 2.7 months with almost two-thirds of patients dropping out within 3 months; 44.3% discontinued medication at the date of study drop-out, and the remainders dropped out due to withdrawal of written consent, logistic reasons, or nonappearance to the study visit, which were not neces-sarily to be equated with cessation of the antipsychotic. Conclusion(s): These fndings indicate that in contrast to RCTs, dropout from observational studies is not necessarily associated with drug discontinuation. Accordingly, systematic differences between trial designs need to be considered when interpreting the results of clinical trials.