Spatio-temporal clustering of the incidence of schizophrenia in Quebec, Canada from 2004 to 2007 André Ngamini Ngui a,⇑ , Philippe Apparicio b , Marie-Josée Fleury d , Alain Lesage c , Jean-Pierre Grégoire e , Jocelyne Moisan e , Alain Vanasse a a Groupe PRIMUS, Centre de recherche Étienne-Lebel, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada b Spatial Analysis and Regional Economics Laboratory, Université du Québec, Institut national de la recherche scientifique, Centre Urbanisation Culture Société, 385 rue Sherbrooke est, Montréal, QC H2X 1E3, Canada c Centre de recherche Fernand-Seguin, Institut universitaire en santé mentale de Montréal, QC, Canada d Douglas Mental Health University Institute, Research Center, McGill University, Montreal, QC, Canada e Faculté de pharmacie, Université Laval and URESP, Centre de recherche du CHU de Québec, Québec, QC, Canada article info Article history: Received 3 April 2012 Revised 30 April 2013 Accepted 31 May 2013 Available online 7 June 2013 Keywords: Schizophrenia Incidence Spatial clusters Administrative data Spatial analyses Spatial epidemiology abstract Exploring spatio-temporal patterns of disease incidence can help to identify areas of signif- icantly elevated or decreased risk, providing potential etiologic clues. In this study, we present a spatio-temporal analysis of the incidence of schizophrenia in Quebec from 2004 to 2007 using administrative databases from the Régie de l’Assurance Maladie du Quebec and the hospital discharge database. We conducted purely spatial analyses for each age group adjusted by sex for the whole period using SatScan (version 9.1.1). Findings from the study indicated variations in the spatial clustering of schizophrenia according to sex and age. In term of incidence rate, there are high differences between urban and rural- remote areas, as well as between the two main metropolitan areas of the province of Que- bec (Island of Montreal and Quebec-City). Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Schizophrenia is a neurological disease and one of the most serious mental illnesses in Canada. Common symp- toms are mixed-up thoughts, delusions (false or irrational beliefs), hallucinations (seeing or hearing things that do not exist) and bizarre behavior. In the general population the prevalence of schizophrenia is estimated to vary be- tween 0.2% and 2%, depending upon the measures used (Goeree et al., 2005; Vanasse et al., 2011). Since there are no laboratory tests to diagnose schizophrenia, diagnosis is based solely on clinical observation. Identifying places with higher risk of schizophrenia may be useful to better target potential intervention programs, and assessing relations be- tween specific neighborhood characteristics and mental health may provide interesting clues in the understanding of the socio-spatial disparities in mental health (Lögberg et al., 2004; Chaix et al., 2006; Kirkbride et al., 2007). Several hypotheses have been used to explain the finding of spatial clusters of schizophrenia in some particular neighborhoods. The ‘‘selection hypothesis’’ theory (Krabbendam and Van Os, 2005) suggests a correlation between urban environment and schizophrenia. However, the complex network of fac- tors that contributes to the cause-effect chain between urbanicity and schizophrenia clustering remains unclear. For instance, in their meta-analytical work, Kelly et al. (2010) came to the conclusion that the possibility of the re- ported association between urbanicity and schizophrenia being entirely attribute to chance is extremely low. Pedersen and Mortensen (2001a,b) even found an evidence of a 1877-5845/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.sste.2013.05.003 ⇑ Corresponding author. Tel.: +1 4506568129. E-mail addresses: ngaminingui@gmail.com (A.N. Ngui), philippe.ap- paricio@ucs.inrs.ca (P. Apparicio), flemar@douglas.mcgill.ca (M.-J. Fleury), alesage@ssss.gouv.qc.ca (A. Lesage), Jean-Pierre.Gregoire@pha.ulaval.ca (J.-P. Grégoire), Jocelyne.Moisan@pha.ulaval.ca (J. Moisan), Alain.Vanas- se@USherbrooke.ca (A. Vanasse). Spatial and Spatio-temporal Epidemiology 6 (2013) 37–47 Contents lists available at SciVerse ScienceDirect Spatial and Spatio-temporal Epidemiology journal homepage: www.elsevier.com/locate/sste