title: Obstetric complications and age at onset in schizophrenia: an international collaborative meta-analysis of individual patient data.
abstract: OBJECTIVE
  An excess of obstetric complications in the histories of schizophrenic patients is a well-replicated finding, but less consistent results have been found concerning the relationships between obstetric complications and family history of schizophrenia, age at onset of schizophrenia, and gender. Small sample size limited the power of previous studies that attempted to assess such relationships. The aim of this study was to use data on individual patients from all available studies to examine the links between a history of obstetric complications and family history of schizophrenia, age at onset, and gender.
  
  
  METHODS
  Raw data from 854 schizophrenic patients concerning history of obstetric complications rated according to the Lewis and Murray scale were obtained from 11 different research groups. Weighted average estimates were calculated with the use of regression techniques.
  
  
  RESULTS
  A significant association was found between age at onset of schizophrenia and obstetric complications: the earlier the age at onset, the more likely the history of obstetric complications. Subjects with onset of schizophrenia before age 22 were 2.7 times more likely than those with onset at a later age to have had a history of abnormal presentation at birth and 10 times more likely to have had a history of complicated Cesarean birth. No association was found between obstetric complications and family history of schizophrenia or gender.
  
  
  CONCLUSIONS
  The association between obstetric complications and early age at onset of schizophrenia indicates that the pathophysiology of early-onset schizophrenia involves neurodevelopmental impairment.
authors.affiliation: Department of Psychiatry, Université Victor Segalen Bordeaux 2, France.
authors.forename: H
authors.initials: H
authors.lastname: Verdoux
authors.forename: J R
authors.initials: JR
authors.lastname: Geddes
authors.forename: N
authors.initials: N
authors.lastname: Takei
authors.forename: S M
authors.initials: SM
authors.lastname: Lawrie
authors.forename: P
authors.initials: P
authors.lastname: Bovet
authors.forename: J M
authors.initials: JM
authors.lastname: Eagles
authors.forename: R
authors.initials: R
authors.lastname: Heun
authors.forename: R G
authors.initials: RG
authors.lastname: McCreadie
authors.forename: T F
authors.initials: TF
authors.lastname: McNeil
authors.forename: E
authors.initials: E
authors.lastname: O'Callaghan
authors.forename: G
authors.initials: G
authors.lastname: Stöber
authors.forename: M U
authors.initials: MU
authors.lastname: Willinger
authors.forename: P
authors.initials: P
authors.lastname: Wright
authors.forename: R M
authors.initials: RM
authors.lastname: Murray
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D002585:Cesarean Section / Q000706:statistics & numerical data; D002648:Child; D005190:Family; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D007744:Obstetric Labor Complications / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D012044:Regression Analysis; D012559:Schizophrenia / Q000453:epidemiology* / Q000235:genetics; D012737:Sex Factors