title: Prenatal life and post-natal psychopathology: evidence for negative gene-birth weight interaction.
abstract: BACKGROUND
  Many studies suggest that pregnancy and birth complications (PBCs) are environmental risk factors for child psychopathology. However, it is not known whether the effects of PBCs occur independently of genetic predisposition. The current study examined the possibility of gene-environment interaction in a twin design.
  
  
  METHODS
  The East Flanders Prospective Twin Survey prospectively records the births of all twin pairs born in East Flanders, Belgium. The current study included 760 twin pairs aged 6-17 years. Multilevel regression analysis was used to assess the effects of several PBCs collected around the time of birth. Using structural equation modelling, ACE models assuming additive genetic (A), shared environmental (C) and unique environmental (E) influences, were compared in order to examine whether the contribution of genetic factors to parent-rated child problem behaviour varied as a function of exposure to dichotomously and continuously defined PBCs.
  
  
  RESULTS
  A main independent effect of lower birth weight, corrected for gestational age (small for gestational age--SGA), on child problem behaviour was found. In addition, there was an interaction between genetic influence and SGA, in that being smaller for gestational age resulted in less influence of additive genetic factors on individual differences in problem behaviour.
  
  
  CONCLUSIONS
  Results are suggestive of negative gene-birth weight interaction. Children who are SGA are less sensitive to the genetic effects, and those with high genetic vulnerability are less sensitive to the effects of being SGA in bringing about post-natal mental health effects.
authors.affiliation: Department of Psychiatry and Neuropsychology, Maastricht University, The Netherlands.
authors.forename: M C
authors.initials: MC
authors.lastname: Wichers
authors.forename: S
authors.initials: S
authors.lastname: Purcell
authors.forename: M
authors.initials: M
authors.lastname: Danckaerts
authors.forename: C
authors.initials: C
authors.lastname: Derom
authors.forename: R
authors.initials: R
authors.lastname: Derom
authors.forename: R
authors.initials: R
authors.lastname: Vlietinck
authors.forename: J
authors.initials: J
authors.lastname: Van Os
mesh_terms: D000293:Adolescent; D002648:Child; D002653:Child Behavior Disorders / Q000235:genetics*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D008957:Models, Genetic; D007744:Obstetric Labor Complications; D011247:Pregnancy; D011248:Pregnancy Complications; D011446:Prospective Studies; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D014427:Twins / Q000523:psychology*