title: Obstetric complications in patients with schizophrenia and their unaffected siblings.
abstract: OBJECTIVE
  We sought to explore whether obstetric complications (OCs) are more likely to occur in the presence of familial/genetic susceptibility for schizophrenia or whether they themselves represent an independent environmental risk factor for schizophrenia.
  
  
  METHODS
  The presence of OCs was assessed through maternal interview on 216 subjects, comprising 36 patients with schizophrenia from multiply affected families, 38 of their unaffected siblings, 31 schizophrenic patients with no family history of psychosis, 51 of their unaffected siblings and 60 normal comparison subjects. We examined the familiality of OCs and whether OCs were commoner in the patient and sibling groups than in the control group.
  
  
  RESULTS
  OCs tended to cluster within families, especially in multiply affected families. Patients with schizophrenia, especially those from multiply affected families, had a significantly higher rate of OCs compared to normal comparison subjects, but there was no evidence for an elevated rate of OCs in unaffected siblings.
  
  
  CONCLUSIONS
  Our data provides little evidence for a link between OCs and genetic susceptibility to schizophrenia. If high rates of OCs are related to schizophrenia genes, this relationship is weak and will only be detected by very large sample sizes.
authors.affiliation: Division of Psychological Medicine, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, London, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Walshe
authors.forename: C
authors.initials: C
authors.lastname: McDonald
authors.forename: M
authors.initials: M
authors.lastname: Taylor
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.forename: P
authors.initials: P
authors.lastname: Sham
authors.forename: A
authors.initials: A
authors.lastname: Grech
authors.forename: K
authors.initials: K
authors.lastname: Schulze
authors.forename: E
authors.initials: E
authors.lastname: Bramon
authors.forename: R M
authors.initials: RM
authors.lastname: Murray
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D016000:Cluster Analysis; D015897:Comorbidity; D005190:Family / Q000523:psychology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics / Q000523:psychology; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D009035:Mothers / Q000523:psychology; D007744:Obstetric Labor Complications / Q000453:epidemiology* / Q000523:psychology; D011247:Pregnancy; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology* / Q000235:genetics; D035781:Siblings / Q000523:psychology*