Inferring causation from cross-sectional data: Examination of the causal relationship between hyperactivity-impulsivity and novelty seeking

Abstract

Previous research suggests an association between hyperactivity-impulsivity one of the two behavioral dimensions that form attention deficit hyperactivity disorderand the temperament characteristic of novelty seeking. We aimed to examine etiological links underlying the cooccurrence between these behaviors using a general population sample of 668 twin pairs, ages 7-10, for whom we obtained parent ratings in middle childhood; and pilot longitudinal data on 76 children. Structural equation modeling confirmed a shared genetic etiology (genetic correlation, rD = 0.81; 95% confidence intervals = 0.34-1.00) and showed that much (64%) of the covariation can be accounted for by shared genetic effects. In addition, causal paths were modeled between the two behaviors; 12% of the variance in novelty seeking at age 7 was accounted for by hyperactive-impulsive behaviors at the same age. The causal effects model fits with the current characterization of hyperactive-impulsive behaviors reflecting a heightened need for stimulation. This has important implications for the management of hyperactive-impulsive behaviors in clinical settings. © 2011 Wood, Rijsdijk, Asherson and Kuntsi.