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Poor stimulus discriminability as a common neuropsychological deficit between ADHD and reading ability in young children: a moderated mediation model

Published online by Cambridge University Press:  04 October 2016

P. S. Lúcio*
Department of Psychiatry, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil Department of Psychology and Psychoanalysis, State University of Londrina (UEL), CEP, Londrina–PR
G. A. Salum
National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil Department of Psychiatry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
L. A. Rohde
National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil Sao Paulo University, Sao Paulo, Brazil
W. Swardfager
Department of Pharmacology & Toxicology, University of Toronto, Toronto, Canada Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, Canada
A. Gadelha
National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil
J. Vandekerckhove
Department of Cognitive Sciences and Department of Statistics, University of California, Irvine, CA, USA
P. M. Pan
Department of Psychiatry, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil
G. V. Polanczyk
National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil
M. C. do Rosário
National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil
A. P. Jackowski
Department of Psychiatry, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil
J. J. Mari
Department of Psychiatry, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil
H. Cogo-Moreira
Department of Psychiatry, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil National Institute of Developmental Psychiatry for Children and Adolescents (INCT-CNPq), Sao Paulo, Brazil
*Address for correspondence: Dr P. S. Lúcio, MS, Departamento de Psicologia e Psicanálise, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid. PR 445 Km 380. Campus Universitário. Cx. Postal 10.011. CEP 86.057-970, Londrina–PR. (Email:



Attention deficit hyperactivity disorder (ADHD) is frequently associated with poorer reading ability; however, the specific neuropsychological domains linking this co-occurrence remain unclear. This study evaluates information-processing characteristics as possible neuropsychological links between ADHD symptoms and RA in a community-based sample of children and early adolescents with normal IQ (⩾70).


The participants (n = 1857, aged 6–15 years, 47% female) were evaluated for reading ability (reading single words aloud) and information processing [stimulus discriminability in the two-choice reaction-time task estimated using diffusion models]. ADHD symptoms were ascertained through informant (parent) report using the Development and Well-Being Assessment (DAWBA). Verbal working memory (VWM; digit span backwards), visuospatial working memory (VSWM, Corsi Blocks backwards), sex, socioeconomic status, and IQ were included as covariates.


In a moderated mediation model, stimulus discriminability mediated the effect of ADHD on reading ability. This indirect effect was moderated by age such that a larger effect was seen among younger children.


The findings support the hypothesis that ADHD and reading ability are linked among young children via a neuropsychological deficit related to stimulus discriminability. Early interventions targeting stimulus discriminability might improve symptoms of inattention/hyperactivity and reading ability.

Original Articles
Copyright © Cambridge University Press 2016 

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