Chunk #50 — Discussion — Structure and Etiology of Behavioral Disinhibition Components Across Adolescence — Individual components of behavioral disinhibition
The genetic and environmental etiology for ADHD was comparable at the two ages. ADHD is a highly stable trait across this adolescent time frame since, unlike conduct problems and substance use, symptoms of ADHD generally manifest earlier in childhood and persist (Kuntsi, Rijsdijk, Ronald, Asherson, & Plomin, 2005). The magnitude of genetic influences on ADHD symptoms in our sample is somewhat smaller than in previously published studies (reviewed in Thapar, 2002), due to higher DZ correlations in our sample than some reported previously (e.g., Rietveld, Hudziak, Bartels, van Beijsterveldt, & Boomsma, 2004). We attribute these higher DZ correlations to the fact that our ADHD composite comprises longitudinal scores from multiple raters (teacher, parent, and self), making it a highly reliable measure that offers a cross-setting index of problem behavior that is less vulnerable to rater contrast effects than parental ratings (Simonoff et al., 1998), which are commonly used in etiologic studies of ADHD.
