Published online by Cambridge University Press: 29 December 2016
Multiple studies have shown that reading abilities and attention-deficit/hyperactivity disorder symptoms, mainly inattention symptoms, are phenotypically and genetically associated during childhood. However, few studies have looked at these associations during adolescence to investigate possible developmental changes. The aim of the study is to examine the genetic and environmental etiology of the associations between inattention and hyperactivity reported by parents, and reading accuracy, reading speed, and word reading in a population-based twin sample (Quebec Newborn Twin Study). Participants were between 14 and 15 years of age at the time of testing (N = 668–837). Phenotypic results showed that when nonverbal and verbal abilities were controlled, inattention, but not hyperactivity/impulsivity, was a modest and significant predictor of reading accuracy, reading speed, and word reading. The associations between inattention and all reading abilities were partly explained by genetic and unique environmental factors. However, the genetic correlations were no longer significant after controlling for verbal abilities. In midadolescence, inattention is the attention-deficit/hyperactivity disorder dimension associated with reading abilities, but they could also share genetic factors with general verbal skills.
This research was supported by grants from the Social Sciences and Humanities Research Council of Canada, the Canadian Institutes of Health Research, and the Quebec Research Funds. Vickie Plourde was supported by a Canadian Institutes of Health Research Doctoral Fellowship. The study received ethical approval from Laval University and Sainte-Justine Hospital. Special thanks to Bei Feng and Hélène Paradis for their assistance in data management; to Marie-Élyse Bertrand for project coordination; and to the children, parents, and teachers who participated in the studies.