The relationship between ADHD and key cognitive phenotypes is not mediated by shared familial effects with IQ
Year: 2010
Type: article
Study design: Observational Study
Abstract: BACKGROUND: Twin and sibling studies have identified specific cognitive phenotypes that may mediate the association between genes and the clinical symptoms of attention deficit hyperactivity disorder (ADHD). ADHD is also associated with lower IQ scores. We aimed to investigate whether the familial association between measures of cognitive performance and the clinical diagnosis of ADHD is mediated through shared familial influences with IQ. METHOD: Multivariate familial models were run on data from 1265 individuals aged 6-18 years, comprising 920 participants from ADHD sibling pairs and 345 control participants. Cognitive assessments included a four-choice reaction time (RT) task, a go/no-go task, a choice-delay task and an IQ assessment. The analyses focused on the cognitive variables of mean RT (MRT), RT variability (RTV), commission errors (CE), omission errors (OE) and choice impulsivity (CI). RESULTS: Significant familial association (rF) was confirmed between cognitive performance and both ADHD (rF=0.41-0.71) and IQ (rF=-0.25 to -0.49). The association between ADHD and cognitive performance was largely independent (80-87%) of any contribution from etiological factors shared with IQ. The exception was for CI, where 49% of the overlap could be accounted for by the familial variance underlying IQ. CONCLUSIONS: The aetiological factors underlying lower IQ in ADHD seem to be distinct from those between ADHD and RT/error measures. This suggests that lower IQ does not account for the key cognitive impairments observed in ADHD. The results have implications for molecular genetic studies designed to identify genes involved in ADHD.
Source: Psychological Medicine
Authors: A. C. Wood, F. Rijsdijk, K. A. Johnson, P. Andreou, B. Albrecht, A. Arias-Vasquez, J. K. Buitelaar, G. McLoughlin, N. N. J. Rommelse, J. A. Sergeant, E. J. S. Sonuga-Barke, H. Uebel, J. J. van der Meere, T. Banaschewski, M. Gill, I. Manor, A. Miranda, F. Mulas, R. D. Oades, H. Roeyers, A. Rothenberger, H. C. Steinhausen, S. V. Faraone, P. Asherson, J. Kuntsi
Institutions: King's College London, University of Alabama at Birmingham, Queen's University Belfast, St. James's Hospital, University of Göttingen, Radboud University Nijmegen, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Vrije Universiteit Amsterdam, Ghent University, University of Southampton, University of Groningen, Heidelberg University, Central Institute of Mental Health, Herzog Hospital, Universitat de València, Hospital Universitari i Politècnic La Fe, University of Duisburg-Essen, University of Basel, University of Zurich, Aalborg University Hospital, Aarhus University Hospital, SUNY Upstate Medical University
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2154185051