Initiating an antipsychotic drug treatment for schizophrenia: the situation in Quebec, Canada, from 1998 to 2006
Objectives To describe factors associated with the following characteristics of the first prescription of an antipsychotic drug treatment (ADT): 1) prescribing physician type (psychiatrist vs. general practitioner); 2) second-generation vs. first-generation antipsychotic drug; 3) in conjunction with at least one additional antipsychotic drug (multitherapy); 4) never renewed by the patient. Methods This is a pharmacoepidemiologic study using administrative data from the Régie de l’assurance maladie du Québec (RAMQ), the public healthcare insurer in Quebec, Canada. Available data sample was exhaustive for adults with a diagnosis of schizophrenia who received an ADT under RAMQ drug coverage from 1998 to 2006. We report multiple logistic regression results. Results Among 16,225 patients who met inclusion criteria 46.2% were women and 70% were beneficiaries of governmental financial assistance. Patients who had their ADT prescribed by psychiatrists tended to be younger and were more burdened by their mental illness. Multitherapy was associated with hospitalization with a psychotic disorder as main diagnosis, lower socioeconomic status, and age between 35 and 64. Second-generation antipsychotic use became progressively more prominent during the period under study. Antipsychotic non renewal was correlated with substance use disorders and was less likely to happen following hospitalization with a psychiatric main diagnosis. Conclusions Although this study is subject to the intrinsic limitations of secondary analysis of administrative data, the database available for study was exhaustive within the Quebec healthcare system and included data from both general practice and specialized care, which allowed us to draw a relevant picture of how ADT were initiated for schizophrenia in Quebec, Canada, from 1998 to 2006. This timeframe is especially relevant since the 1990s were marked by the introduction of second-generation antipsychotics in Canada.