title: Explaining variation in the premorbid adjustment of schizophrenia patients: the role of season of birth and family history.
abstract: Several studies have shown that patients with schizophrenia are more likely to be born in the winter and early spring than at any other time of the year. Furthermore, some studies have reported that winter-born patients differ from non-winter-born patients in terms of risk factors, symptoms, sensory abnormalities and brain morphology. Associations between season of birth and premorbid adjustment (PMA), however, are still unclear.
  
  
  OBJECTIVE
  The main purpose of this study was to determine whether winter-born and non-winter-born schizophrenia patients differ in terms of PMA and to examine how family history of schizophrenia-spectrum disorders may influence the association.
  
  
  METHODS
  Data on four PMA dimensions (attention, internalizing, externalizing and social problems) and family history were gathered from 37 schizophrenia patients (26 males and 11 females) and their mothers.
  
  
  RESULTS
  Non-winter-birth and a positive family history of schizophrenia-spectrum disorders were associated with worse PMA. Results suggest that, although no significant interaction was found, season of birth and family history appear to work together in explaining distinct dimensions of PMA.
authors.affiliation: Kent State University, Department of Psychology, P.O. Box 5190, Kent, OH 44242, USA.
authors.forename: Annie
authors.initials: A
authors.lastname: St-Hilaire
authors.forename: Darren
authors.initials: D
authors.lastname: Holowka
authors.forename: Helen
authors.initials: H
authors.lastname: Cunningham
authors.forename: Frances
authors.initials: F
authors.lastname: Champagne
authors.forename: Monica
authors.initials: M
authors.lastname: Pukall
authors.forename: Suzanne
authors.initials: S
authors.lastname: King
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention; D005190:Family; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000453:epidemiology* / Q000235:genetics*; D012621:Seasons; D012919:Social Behavior