title: Inverse relationship of perinatal complications and eye tracking dysfunction in relatives of patients with schizophrenia: evidence for a two-factor model.
abstract: OBJECTIVE
  Because both smooth pursuit eye tracking dysfunction and obstetrical complications are significant risk factors for schizophrenia, the authors tested the predictions of a two-factor model of how eye tracking dysfunction and obstetrical complications covary in patients with schizophrenia, their siblings, and comparison subjects.
  
  
  METHODS
  Psychiatric diagnoses, eye tracking dysfunction, and obstetrical complications noted in birth records were independently assessed in 18 patients with schizophrenia, 16 of their siblings without schizophrenia, and 49 comparison subjects with neither personal nor family histories of schizophrenia.
  
  
  RESULTS
  As hypothesized, 1) the combination of eye tracking dysfunction and perinatal obstetrical complications discriminated patients with schizophrenia significantly from subjects without schizophrenia, including siblings of patients with schizophrenia, and 2) eye tracking dysfunction and perinatal obstetrical complications manifested a significant inverse association in the nonschizophrenic siblings of patients with schizophrenia.
  
  
  CONCLUSIONS
  These results support a two-factor model in which obstetrical complications often interact with genetic liability, indicated by eye tracking dysfunction, to produce schizophrenia.
authors.affiliation: Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Kinney
authors.forename: D L
authors.initials: DL
authors.lastname: Levy
authors.forename: D A
authors.initials: DA
authors.lastname: Yurgelun-Todd
authors.forename: S J
authors.initials: SJ
authors.lastname: Tramer
authors.forename: P S
authors.initials: PS
authors.lastname: Holzman
mesh_terms: D000328:Adult; D015897:Comorbidity; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D008957:Models, Genetic; D008962:Models, Theoretical; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D015835:Ocular Motility Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D011247:Pregnancy; D011698:Pursuit, Smooth; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics