title: Season of birth and subclinical psychosis: systematic review and meta-analysis of new and existing data.
abstract: Season of birth (SOB) has been shown to modify the risk of several health outcomes, including a number of neuropsychiatric disorders. Empirical evidence indicates that subclinical forms of psychosis in the general population share some risk factors with categorical diagnoses of psychosis. Hence, by systematically reviewing and meta-analyzing new and existing data, the current work aimed to determine whether there is evidence of an association between winter SOB and subclinical psychosis in the general population. Our meta-analytic results do not indicate an association between winter SOB and schizotypy in adult populations, although they indicate winter SOB may be a risk factor for psychotic experiences or symptoms in children around 12-15 years (OR=1.12, 95%CI:1.03-1.21). In the whole new dataset for adults (n=481, mean age=22.8 years) no association was detected in either an unadjusted model or adjusting for gender and age. Overall, our results indicate that the association between winter SOB and increased subclinical psychosis may hold in children, but does not in the broad general adult population. Nevertheless, the epidemiological and clinicopathological significance of winter SOB as a risk factor for subclinical psychosis would probably be slight due to the small effect sizes indicated by the reports available to date.
authors.affiliation: Unidad de Antropología, Departamento de Biología Animal, Facultad de Biología and Instituto de Biomedicina (IBUB), Universitat de Barcelona, Av. Diagonal, 643, 08028 Barcelona, Spain; Centro de Investigaciones Biomédicas en Red de Salud Mental (CIBERSAM), C/Doctor Esquerdo, 46, 28007 Madrid, Spain.
authors.forename: Aldo
authors.initials: A
authors.lastname: Córdova-Palomera
authors.affiliation: INSERM U1061, FondaMental Foundation, University of Montpellier, Av. du doyen Gaston-Giraud, 191, 34295, Montpellier, France.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Calati
authors.affiliation: Unidad de Antropología, Departamento de Biología Animal, Facultad de Biología and Instituto de Biomedicina (IBUB), Universitat de Barcelona, Av. Diagonal, 643, 08028 Barcelona, Spain; Centro de Investigaciones Biomédicas en Red de Salud Mental (CIBERSAM), C/Doctor Esquerdo, 46, 28007 Madrid, Spain.
authors.forename: Bárbara
authors.initials: B
authors.lastname: Arias
authors.affiliation: Centro de Investigaciones Biomédicas en Red de Salud Mental (CIBERSAM), C/Doctor Esquerdo, 46, 28007 Madrid, Spain; Department of Basic and Clinical Psychology and Psychobiology, Faculty of Health Sciences, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071 Castelló, Spain.
authors.forename: Manuel-Ignacio
authors.initials: MI
authors.lastname: Ibáñez
authors.affiliation: Centro de Investigaciones Biomédicas en Red de Salud Mental (CIBERSAM), C/Doctor Esquerdo, 46, 28007 Madrid, Spain; Department of Pedagogy and Psychology, Faculty of Education, Psychology and Social Work, University of Lleida, Av. de l׳Estudi General, 4, 25001 Lleida, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Moya
authors.affiliation: Centro de Investigaciones Biomédicas en Red de Salud Mental (CIBERSAM), C/Doctor Esquerdo, 46, 28007 Madrid, Spain; Department of Basic and Clinical Psychology and Psychobiology, Faculty of Health Sciences, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071 Castelló, Spain.
authors.forename: Generós
authors.initials: G
authors.lastname: Ortet
authors.affiliation: Centro de Investigaciones Biomédicas en Red de Salud Mental (CIBERSAM), C/Doctor Esquerdo, 46, 28007 Madrid, Spain; University Hospital Marqués de Valdecilla, Department of Psychiatry, School of Medicine, University of Cantabria,Av. Valdecilla, s/n, 39008 Santander Cantabria, Spain; IDIVAL, Valdecilla Biomedical Research Institute, Av. Valdecilla, s/n, 39008, Santander, Spain.
authors.forename: Benedicto
authors.initials: B
authors.lastname: Crespo-Facorro
authors.affiliation: Unidad de Antropología, Departamento de Biología Animal, Facultad de Biología and Instituto de Biomedicina (IBUB), Universitat de Barcelona, Av. Diagonal, 643, 08028 Barcelona, Spain; Centro de Investigaciones Biomédicas en Red de Salud Mental (CIBERSAM), C/Doctor Esquerdo, 46, 28007 Madrid, Spain. Electronic address: lfananas@ub.edu.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Fañanás
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D011618:Psychotic Disorders / Q000453:epidemiology*; D012621:Seasons; D055815:Young Adult
keywords: General population; Schizotypy; Season of birth; Seasonality; Subclinical psychosis; Winter birth