title: A study of genetic and environmental effects on the co-occurrence of problem behaviors in three-year-old twins.
abstract: The authors examined the genetic and environmental causes of the co-occurrence of problem behaviors in children. The analyses involved mother and father ratings of Oppositional, Withdrawn/Depressed, Aggressive, Anxious, Overactive, and Sleep Problems in 446 monozygotic and 912 dizygotic pairs of 3-year-old twins. Genetic factors contributed on average .150 (37.3%), shared environment .206 (51.2%), and nonshared environment .046 (11.4%) to the phenotypic correlations between the syndromes. Genetic and environmental factors caused different groupings. Internalizing and Externalizing groupings were indicative of nonshared environmental factors; clusters of problem behaviors with either the Aggressive or Anxious symptoms were most suggestive of genetic factors, and high scores on all syndromes indicated shared environmental influences.
authors.affiliation: Utrecht U.
authors.forename: Edwin J C G
authors.initials: EJCG
authors.lastname: Van den Oord
authors.forename: Dorret I
authors.initials: DI
authors.lastname: Boomsma
authors.forename: Frank C
authors.initials: FC
authors.lastname: Verhulst
mesh_terms: D002653:Child Behavior Disorders / Q000235:genetics* / Q000523:psychology; D002675:Child, Preschool; D004200:Diseases in Twins / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D010552:Personality Assessment; D012307:Risk Factors; D012931:Social Environment