title: Paternal and maternal ages have contrasting associations with self-reported schizophrenia liability.
abstract: BACKGROUND
  Older paternal age predicts schizophrenia diagnosis in offspring. If this relationship reflects a pathogenic process, paternal age should predict the expression of subclinical schizophrenia liability (schizotypy). We hypothesized that paternal and maternal ages predict positive, negative, and disorganized features of schizotypy, that family history of psychosis moderates the relationship of paternal age with schizotypy, and that stress sensitivity mediates the relationship of maternal age with schizotypy.
  
  
  METHODS
  Two studies are reported, each of undergraduates (n=500 and n=211) who completed the Schizotypal Personality Questionnaire. The second was designed to replicate and extend the first and included assessment of stress sensitivity.
  
  
  RESULTS
  In Study 1, older paternal age and younger maternal age predicted greater positive schizotypy (β=.13 and β=-.19, respectively). Parental ages did not predict negative or disorganized features and family history did not moderate the paternal age association. In Study 2, the same pattern of associations between parental ages and schizotypy components was observed. Additionally, stress sensitivity partially mediated the association of maternal age with positive schizotypy whereas it did not contribute to the paternal age association.
  
  
  CONCLUSIONS
  The association between older paternal age and schizophrenia extends to self-reported positive features of schizophrenia liability, consistent with the notion that this relationship arises from a pathogenic process, such as de novo mutations. Importantly, younger maternal age was an equally potent predictor of positive schizotypy, with its association partially mediated by stress sensitivity.
authors.affiliation: Department of Psychology, University of Otago, New Zealand.
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Grattan
authors.affiliation: Department of Psychology, University of Otago, New Zealand.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Morton
authors.affiliation: Department of Psychology, University of Otago, New Zealand.
authors.forename: Ellen S
authors.initials: ES
authors.lastname: Warhurst
authors.affiliation: Department of Psychology, University of Otago, New Zealand.
authors.forename: Theresa R
authors.initials: TR
authors.lastname: Parker
authors.affiliation: Department of Psychology, University of Otago, New Zealand.
authors.forename: Max P
authors.initials: MP
authors.lastname: Nicolson
authors.affiliation: Department of Psychology, University of Otago, New Zealand.
authors.forename: Jaimee L K
authors.initials: JLK
authors.lastname: Maha
authors.affiliation: Department of Psychology, University of Otago, New Zealand; Department of Psychiatry and Psychology, Maastricht University, Maastricht, The Netherlands. Electronic address: linscott@psy.otago.ac.nz.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Linscott
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D010331:Paternal Age; D010555:Personality Inventory; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology; D057566:Self Report; D055815:Young Adult
keywords: De novo mutations; Environmental risk factors; Maternal age; Paternal age; Psychotic experiences; Schizotypal personality; Schizotypy; Stress sensitivity