Original article Winter birth, urbanicity and immigrant status predict psychometric schizotypy dimensions in adolescents D. Mimarakis Q1 a , T. Roumeliotaki b , P. Roussos c,d,e , S.G. Giakoumaki f , P. Bitsios a, * a Department Q2 of Psychiatry and Behavioral Sciences, University of Crete, Heraklion, Greece b Department of Social Medicine, University of Crete, Heraklion, Greece c Department of Q3 Psychiatry and Friedman Brain Institute, United States d Department Q4 of Genetics and Genomic Sciences and Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, New York, 10029, United States e Mental Illness Research Education and Clinical Center (MIRECC), James J. Peters VA Medical Center, Bronx, New York, 10468, United States f Department of Psychology, University of Crete, Rethymnon, Greece 1. Introduction Schizophrenia is a serious psychiatric disorder with a hetero- geneous genetic and neurobiological background that alters early brain development and maturation, ultimately affecting informa- tion processing, motivation and cognition [1]. The neurodevelop- mental model posits that the phenomenological diagnosis of schizophrenia based on the expression of hallucinations, delusions and disorganization typically around late adolescence-early adulthood, is the end stage of abnormal neurodevelopmental processes that began years before [2]. Stable epidemiological risk factors for schizophrenia, such as being winter-born [3], urbanicity [4] and immigration [5] have been identified, with the vast majority of this research focusing on adult psychosis. Yet, urban residency from birth to adolescence, rather than during adulthood, appears to be more strongly associated with adult psychosis [6–8] and it is the post-migratory family-social context interactions rather than pre- or peri-migrational factors that mediate the risk for psychosis [5]. Consistent with the neurodevelopmental model of schizophrenia, the above suggest that the processes leading from urban exposure or immigration to psychosis begin in adolescence, childhood or earlier. Schizotypy is a subclinical construct tapping normative dispositions toward characteristics that are associated with European Psychiatry xxx (2017) xxx–xxx * Corresponding author. E-mail address: bitsiosp@uoc.gr (P. Bitsios). A R T I C L E I N F O Article history: Received 3 May 2017 Received in revised form 29 July 2017 Accepted 30 July 2017 Available online xxx Keywords: Adolescence Personality Schizophrenia Risk factors Environment A B S T R A C T Background: Urbanicity, immigration and winter-birth are stable epidemiological risk factors for schizophrenia, but their relationship to schizotypy is unknown. This is a first examination of the association of these epidemiological risk factors with positive schizotypy, in nonclinical adolescents, controlling for a range of potential and known confounders. Methods: We collected socio-demographics, life-style, family and school circumstances, positive schizotypy dimensions and other personality traits from 445 high school pupils (192 males, 158 immigrants) from 9 municipalities in Athens and Heraklion, Greece, which covered a range of host population and migrant densities. Using multivariate hierarchical linear regressions models, we estimated the association of schizotypy dimensions with: (1) demographics of a priori interest (winter- birth, immigrant status, urban characteristics), including family financial and mental health status; (2) factors resulting from principal component analysis (PCA) of the demographic and personal data; (3) factors resulting from PCA of the personality questionnaires. Results: Adolescent women scored higher on schizotypy than men. High anxiety/neuroticism was the most consistent and significant predictor of all schizotypy dimensions in both sexes. In the fully adjusted models, urbanicity predicted magical thinking and unusual experiences in women, while winter-birth and immigration predicted paranoid ideation and unusual experiences respectively in men. Conclusions: These results support the continuum hypothesis and offer potential insights in the nature of risk conferred by winter-birth, urbanicity and immigration and the nature of important sex differences. Controlling for a wide range of potential confounding factors increases the robustness of these results and confidence that these were not spurious associations.  C 2017 Elsevier Masson SAS. All rights reserved. G Model EURPSY 3566 1–10 Please cite this article in press as: Mimarakis D, et al. Winter birth, urbanicity and immigrant status predict psychometric schizotypy dimensions in adolescents. European Psychiatry (2017), http://dx.doi.org/10.1016/j.eurpsy.2017.07.014 Contents lists available at ScienceDirect European Psychiatry jo u rn al h om epag e: h ttp ://ww w.eu ro p s y- jo ur n al.co m http://dx.doi.org/10.1016/j.eurpsy.2017.07.014 0924-9338/  C 2017 Elsevier Masson SAS. All rights reserved.