title: Continuity and change in preschool ADHD symptoms: longitudinal genetic analysis with contrast effects.
abstract: The genetic and environmental mediation of continuity and change in parent-reported ADHD symptoms were investigated in a cohort of over 6000 twin pairs at 2, 3 and 4 years of age. Genetic analyses of the cross-sectional data yielded heritability estimates of 0.78-0.81 at each age, with contrast effects. A common pathway model provided the best fit to the longitudinal data, indicating that genetic influences underlie 91% of the stable variance in ADHD symptomatology. In other words, what is stable for ADHD symptoms is largely genetic. Contrast effects acting in the same direction at different ages contributed to the observed continuity:longitudinal correlations were greater for dizygotic than monozygotic twins.
authors.affiliation: Wellcome Trust Centre for Human Genetics, University of Oxford, UK. tprice@well.ox.ac.uk
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Price
authors.forename: Emily
authors.initials: E
authors.lastname: Simonoff
authors.forename: Philip
authors.initials: P
authors.lastname: Asherson
authors.forename: Sarah
authors.initials: S
authors.lastname: Curran
authors.forename: Jonna
authors.initials: J
authors.lastname: Kuntsi
authors.forename: Irwin
authors.initials: I
authors.lastname: Waldman
authors.forename: Robert
authors.initials: R
authors.lastname: Plomin
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics*; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004739:England; D006801:Humans; D008137:Longitudinal Studies; D008960:Models, Psychological; D002666:Psychology, Child; D018433:Twin Studies as Topic; D014852:Wales