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Shero JA, Logan JAR, Petrill SA, Willcutt E, Hart SA. The Differential Relations Between ADHD and Reading Comprehension: A Quantile Regression and Quantile Genetic Approach. Behav Genet 2021; 51:631-653. [PMID: 34302587 PMCID: PMC8715540 DOI: 10.1007/s10519-021-10077-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/13/2021] [Indexed: 10/20/2022]
Abstract
This paper extends the understanding of the relation between ADHD and reading comprehension, through examining how this relation differs depending on the quantile an individual falls in for each. Samples from three twin projects around the United States were used (Florida Twin Project, Colorado component of International Longitudinal Twin Study of Early Reading Development, & Western Reserve Reading and Math Projects). Phenotypic analysis using quantile regression showed relations between ADHD related behaviors and reading comprehension to be stronger in the lower quantiles of reading comprehension in two of three samples. A new method was developed extending this analysis into the bivariate genetic space. Results of this quantile genetic analysis revealed that overlapping common environmental influences accounted for a larger proportion of variance in the lower quantiles of these variables in two of three samples. Finally, in all three samples the phenotypic relation was strongest when shared environmental influences accounted for a larger proportion of the overall variance.
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Affiliation(s)
- Jeffrey A Shero
- Department of Psychology, Florida State University, 1107 W. Call Street, Tallahassee, FL, 32308, USA.
| | - Jessica A R Logan
- Department of Educational Studies, The Ohio State University, Columbus, OH, USA
| | - Stephen A Petrill
- Department of Psychology, The Ohio State University, Columbus, OH, USA
| | - Erik Willcutt
- Department of Psychology, University of Colorado Boulder, Boulder, CO, USA
| | - Sara A Hart
- Department of Psychology, Florida State University, 1107 W. Call Street, Tallahassee, FL, 32308, USA
- Florida Center for Reading Research, Tallahassee, FL, USA
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Daucourt MC, Erbeli F, Little CW, Haughbrook R, Hart SA. A Meta-Analytical Review of the Genetic and Environmental Correlations between Reading and Attention-Deficit Hyperactivity Disorder Symptoms and Reading and Math. SCIENTIFIC STUDIES OF READING : THE OFFICIAL JOURNAL OF THE SOCIETY FOR THE SCIENTIFIC STUDY OF READING 2019; 24:23-56. [PMID: 32189961 PMCID: PMC7079676 DOI: 10.1080/10888438.2019.1631827] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 06/03/2019] [Accepted: 06/11/2019] [Indexed: 05/28/2023]
Abstract
According to the Multiple Deficit Model, comorbidity results when the genetic and environmental risk factors that increase the liability for a disorder are domain-general. In order to explore the role of domain-general etiological risk factors in the co-occurrence of learning-related difficulties, the current meta-analysis compiled 38 studies of third through ninth-grade children to estimate the average genetic, shared environmental, and nonshared environmental correlations between reading and attention-deficit/hyperactivity disorder (ADHD) symptoms, and reading and math, as well as their potential moderators. Results revealed average genetic, shared and nonshared environmental correlations between reading and ADHD symptoms of .42, .64, and .20, and reading and math of .71, .90, and .56, suggesting that reading and math may have more domain-general risk factors than reading and ADHD symptoms. A number of significant sources of heterogeneity were also found and discussed. These results have important implications for both intervention and classification of learning disabilities.
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Affiliation(s)
- Mia C. Daucourt
- Florida State University, Department of Psychology, Tallahassee, FL, USA
| | - Florina Erbeli
- Texas A&M University, Department of Educational Psychology, College Station, TX, USA
| | - Callie W. Little
- University of New England, School of Psychology & Behavioural Sciences, Armidale, Australia
| | - Rasheda Haughbrook
- Florida State University, Department of Psychology, Tallahassee, FL, USA
| | - Sara A. Hart
- Florida State University, Department of Psychology, Tallahassee, FL, USA
- Florida State University, Florida Center for Reading Research, Tallahassee, FL, USA
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Tse L, Nicholson T. The effect of phonics-enhanced Big Book reading on the language and literacy skills of 6-year-old pupils of different reading ability attending lower SES schools. Front Psychol 2014; 5:1222. [PMID: 25431560 PMCID: PMC4230049 DOI: 10.3389/fpsyg.2014.01222] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 10/09/2014] [Indexed: 11/13/2022] Open
Abstract
The purpose of this study was to improve the literacy achievement of lower socioeconomic status (SES) children by combining explicit phonics with Big Book reading. Big Book reading is a component of the text-centered (or book reading) approach used in New Zealand schools. It involves the teacher in reading an enlarged book to children and demonstrating how to use semantic, syntactic, and grapho-phonic cues to learn to read. There has been little research, however, to find out whether the effectiveness of Big Book reading is enhanced by adding explicit phonics. In this study, a group of 96 second graders from three lower SES primary schools in New Zealand were taught in 24 small groups of four, tracked into three different reading ability levels. All pupils were randomly assigned to one of four treatment conditions: a control group who received math instruction, Big Book reading enhanced with phonics (BB/EP), Big Book reading on its own, and Phonics on its own. The results showed that the BB/EP group made significantly better progress than the Big Book and Phonics groups in word reading, reading comprehension, spelling, and phonemic awareness. In reading accuracy, the BB/EP and Big Book groups scored similarly. In basic decoding skills the BB/EP and Phonics groups scored similarly. The combined instruction, compared with Big Book reading and phonics, appeared to have no comparative disadvantages and considerable advantages. The present findings could be a model for New Zealand and other countries in their efforts to increase the literacy achievement of disadvantaged pupils.
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Affiliation(s)
- Laura Tse
- School of Curriculum and Pedagogy, The University of Auckland Auckland, New Zealand
| | - Tom Nicholson
- Institute of Education, Massey University Auckland, New Zealand
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Abstract
The present study examined genetic and shared environment contributions to quantitatively-measured autism symptoms and categorically-defined autism spectrum disorders (ASD). Participants included 568 twins from the Interactive Autism Network. Autism symptoms were obtained using the Social Communication Questionnaire and Social Responsiveness Scale. Categorically-defined ASD was based on clinical diagnoses. DeFries-Fulker and liability threshold models examined etiologic influences. Very high heritability was observed for extreme autism symptom levels ([Formula: see text]). Extreme levels of social and repetitive behavior symptoms were strongly influenced by common genetic factors. Heritability of categorically-defined ASD diagnosis was comparatively low (.21, 95 % CI 0.15-0.28). High heritability of extreme autism symptom levels confirms previous observations of strong genetic influences on autism. Future studies will require large, carefully ascertained family pedigrees and quantitative symptom measurements.
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Emam MM, Kazem AM. Teachers’ perceptions of the concomitance of emotional behavioural difficulties and learning disabilities in children referred for learning disabilities in Oman. EMOTIONAL AND BEHAVIOURAL DIFFICULTIES 2014. [DOI: 10.1080/13632752.2014.964083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Peterson RL, Pennington BF, Samuelsson S, Byrne B, Olson RK. Shared etiology of phonological memory and vocabulary deficits in school-age children. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2013; 56:1249-59. [PMID: 23275423 PMCID: PMC3615120 DOI: 10.1044/1092-4388(2012/12-0185)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PURPOSE The goal of this study was to investigate the etiologic basis for the association between deficits in phonological memory (PM) and vocabulary in school-age children. METHOD Children with deficits in PM or vocabulary were identified within the International Longitudinal Twin Study (ILTS; Samuelsson et al., 2005). The ILTS includes 1,045 twin pairs (between the ages of 5 and 8 years) from the United States, Australia, and Scandinavia. The authors applied the DeFries-Fulker ( DeFries & Fulker, 1985, 1988) regression method to determine whether problems in PM and vocabulary tend to co-occur because of overlapping genes, overlapping environmental risk factors, or both. RESULTS Among children with isolated PM deficits, the authors found significant bivariate heritability of PM and vocabulary weaknesses both within and across time. However, when probands were selected for a vocabulary deficit, there was no evidence for bivariate heritability. In this case, it appears that the PM-vocabulary relationship is caused by common shared environmental experiences. CONCLUSIONS The findings are consistent with previous research on the heritability of specific language impairment and suggest that there are etiologic subgroups of children with low vocabulary for different reasons, 1 being more influenced by genes and another being more influenced by environment.
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Humayun S, Kahn RE, Frick PJ, Viding E. Callous-unemotional traits and anxiety in a community sample of 7-year-olds. JOURNAL OF CLINICAL CHILD AND ADOLESCENT PSYCHOLOGY 2013; 43:36-42. [PMID: 23879532 PMCID: PMC4131266 DOI: 10.1080/15374416.2013.814539] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In forensic samples of adults and adolescents, there is evidence to suggest that there may be distinct variants of psychopathy marked by the presence/absence of significant levels of anxiety. Callous-unemotional (CU) traits can be used to characterize children who share behavioural and neurocognitive features with adult psychopaths. The aims of this paper are to (a) investigate the genetic and environmental influences on CU traits with/without anxiety and (b) explore differences in terms of concurrent and early parenting and adjustment. Discrete groups were formed on the basis of scores in the top 10% of the sample on CU and anxiety scales at age 7. Estimates of group heritability were calculated using a Defries-Fulker (DF) extremes regression model. Follow back analyses of early parenting and adjustment were conducted using multivariate analyses of covariance. There was high group heritability for CU traits with/without anxiety. Children with both high CU and anxiety showed greater levels of adjustment problems than those with CU only at age 7. The two groups did not differ in parenting characteristics. In this general population sample, evidence did not support differences in etiology for the two groups high on CU traits differing in level of anxiety.
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Affiliation(s)
- Sajid Humayun
- a Developmental Risk and Resilience Unit, University College London, Newham College University Centre
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Raskind WH, Peter B, Richards T, Eckert MM, Berninger VW. The genetics of reading disabilities: from phenotypes to candidate genes. Front Psychol 2013; 3:601. [PMID: 23308072 PMCID: PMC3538356 DOI: 10.3389/fpsyg.2012.00601] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 12/18/2012] [Indexed: 12/19/2022] Open
Abstract
This article provides an overview of (a) issues in definition and diagnosis of specific reading disabilities at the behavioral level that may occur in different constellations of developmental and phenotypic profiles (patterns); (b) rapidly expanding research on genetic heterogeneity and gene candidates for dyslexia and other reading disabilities; (c) emerging research on gene-brain relationships; and (d) current understanding of epigenetic mechanisms whereby environmental events may alter behavioral expression of genetic variations. A glossary of genetic terms (denoted by bold font) is provided for readers not familiar with the technical terms.
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Affiliation(s)
- Wendy H Raskind
- Department of Medicine, University of Washington Seattle, WA, USA ; Department of Psychiatry and Behavioral Sciences, University of Washington Seattle, WA, USA
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Cheung CH, Wood AC, Paloyelis Y, Arias-Vasquez A, Buitelaar JK, Franke B, Miranda A, Mulas F, Rommelse N, Sergeant JA, Sonuga-Barke EJ, Faraone SV, Asherson P, Kuntsi J. Aetiology for the covariation between combined type ADHD and reading difficulties in a family study: the role of IQ. J Child Psychol Psychiatry 2012; 53:864-73. [PMID: 22324316 PMCID: PMC3414694 DOI: 10.1111/j.1469-7610.2012.02527.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Twin studies using both clinical and population-based samples suggest that the frequent co-occurrence of attention deficit hyperactivity disorder (ADHD) and reading ability/disability (RD) is largely driven by shared genetic influences. While both disorders are associated with lower IQ, recent twin data suggest that the shared genetic variability between reading difficulties and ADHD inattention symptoms is largely independent from genetic influences contributing to general cognitive ability. The current study aimed to extend the previous findings that were based on rating scale measures in a population sample by examining the generalisability of the findings to a clinical population, and by measuring reading difficulties both with a rating scale and with an objective task. This study investigated the familial relationships between ADHD, reading difficulties and IQ in a sample of individuals diagnosed with ADHD combined type, their siblings and control sibling pairs. METHODS Multivariate familial models were run on data from 1,789 individuals at ages 6-19. Reading difficulties were measured with both rating scale and an objective task. IQ was obtained using the Wechsler Intelligence Scales (WISC-III/WAIS-III). RESULTS Significant phenotypic (.2-.4) and familial (.3-.5) correlations were observed among ADHD, reading difficulties and IQ. Yet, 53%-72% of the overlapping familial influences between ADHD and reading difficulties were not shared with IQ. CONCLUSIONS Our finding that familial influences shared with general cognitive ability, although present, do not account for the majority of the overlapping familial influences on ADHD and reading difficulties extends previous findings from a population-based study to a clinically ascertained sample with combined type ADHD.
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Affiliation(s)
- Celeste H.M. Cheung
- King’s College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, UK
| | - Alexis C. Wood
- Department of Epidemiology and Section of Statistical Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yannis Paloyelis
- King’s College London, Department of Neuroimaging and Department of Psychology, Institute of Psychiatry, UK
| | - Alejandro Arias-Vasquez
- Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands,Department of Psychiatry, Donders Institute for Brain, Cognition and Behavior, Centre for Neuroscience, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Jan K. Buitelaar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Centre for Neuroscience, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Barbara Franke
- Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands,Department of Psychiatry, Donders Institute for Brain, Cognition and Behavior, Centre for Neuroscience, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Ana Miranda
- Department of Developmental and Educational Psychology, University of Valencia, Spain
| | - Fernando Mulas
- Department of Neuropaediatrics, La Fe University Hospital, Faculty of Medicine, Valencia, Spain
| | - Nanda Rommelse
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behavior, Centre for Neuroscience, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Joseph A. Sergeant
- Department of Clinical Neuropsychology, Vrije Universiteit, Amsterdam, The Netherlands
| | - Edmund J. Sonuga-Barke
- Developmental Brain-Behaviour Laboratory, University of Southampton, UK,Department of Experimental Clinical and Health Psychology, Ghent University, Belgium
| | - Stephen V. Faraone
- Department of Neuroscience, SUNY Upstate Medical University, Syracuse, NY, USA,Department of Psychiatry, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Philip Asherson
- King’s College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, UK
| | - Jonna Kuntsi
- King’s College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, UK
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An association study of sequence variants in the forkhead box P2 (FOXP2) gene and adulthood attention-deficit/hyperactivity disorder in two European samples. Psychiatr Genet 2012; 22:155-60. [DOI: 10.1097/ypg.0b013e328353957e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Rosenberg J, Pennington BF, Willcutt EG, Olson RK. Gene by environment interactions influencing reading disability and the inattentive symptom dimension of attention deficit/hyperactivity disorder. J Child Psychol Psychiatry 2012; 53:243-51. [PMID: 21884522 PMCID: PMC3235245 DOI: 10.1111/j.1469-7610.2011.02452.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Reading disability (RD) and attention deficit/hyperactivity disorder (ADHD) are comorbid and genetically correlated, especially the inattentive dimension of ADHD (ADHD-I). However, previous research indicates that RD and ADHD enter into opposite gene by environment (G × E) interactions. METHODS This study used behavioral genetic methods to replicate these opposite G × E interactions in a sample of same-sex monozygotic and dizygotic twin pairs from the Colorado Learning Disabilities Research Center (CLDRC; DeFries et al., 1997) and to test a genetic hypothesis for why these opposite interactions occur. RESULTS We replicated opposite G × E interactions for RD (bioecological) and ADHD-I (diathesis-stress) with parental education in the same sample of participants. The genetic hypothesis for this opposite pattern of interactions is that only genes specific to each disorder enter into these opposite interactions, not the shared genes underlying their comorbidity. To test this hypothesis, we used single models with an exploratory three-way interaction, in which the G × E interactions for each disorder were moderated by comorbidity. Neither three-way interaction was significant. The heritability of RD did not vary as a function of parental education and ADHD-I. Similarly, the heritability of ADHD-I did not vary as a function of parental education and RD. CONCLUSIONS We documented opposite G × E interactions in RD and ADHD-I in the same overall twin sample, but the explanation for this apparent paradox remains unclear. Examining specific genes and more specific environmental factors may help resolve the paradox.
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Affiliation(s)
- Jenni Rosenberg
- Department of Psychology, University of Denver, Denver, CO 80208-0001, USA.
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Robinson EB, Koenen KC, McCormick MC, Munir K, Hallett V, Happé F, Plomin R, Ronald A. A multivariate twin study of autistic traits in 12-year-olds: testing the fractionable autism triad hypothesis. Behav Genet 2012; 42:245-55. [PMID: 21927971 PMCID: PMC3256271 DOI: 10.1007/s10519-011-9500-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Accepted: 08/20/2011] [Indexed: 10/17/2022]
Abstract
Autistic traits-social impairment, communication impairment, and restricted and repetitive behaviors and interests-are heritable in the general population. Previous analyses have consistently reported limited genetic and environmental overlap between autistic trait domains in samples assessed in middle childhood. Here we extend this research to parent-report data for 12-year-olds. Data from 5,944 pairs in the Twins Early Development Study were analyzed to explore the domain-specific heritability and degree of shared genetic and environmental influences across different autistic traits in the general population and among individuals scoring in the top 5% of each domain. Sex differences in the etiological estimates were also tested in these analyses. Autistic traits were moderately to highly heritable (0.58-0.88) at age 12. Bivariate genetic correlations in the full sample (0.18-0.40) and the extremes (0.24-0.67), as well as even lower unique environmental correlations, all suggested considerable fractionation of genetic and environmental influences across autistic trait domains, in line with previous findings.
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Affiliation(s)
- Elise B Robinson
- Department of Epidemiology, Harvard School of Public Health, 185 Cambridge St., Boston, MA 02114, USA.
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Semrud-Clikeman M. The Role of Inattention on Academics, Fluid Reasoning, and Visual–Spatial Functioning in Two Subtypes of ADHD. APPLIED NEUROPSYCHOLOGY-CHILD 2012; 1:18-29. [DOI: 10.1080/21622965.2012.665766] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Sylva K, Scott S, Totsika V, Ereky-Stevens K, Crook C. Training parents to help their children read: A randomized control trial. BRITISH JOURNAL OF EDUCATIONAL PSYCHOLOGY 2010; 78:435-55. [DOI: 10.1348/000709907x255718] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Willcutt EG, Betjemann RS, McGrath LM, Chhabildas NA, Olson RK, DeFries JC, Pennington BF. Etiology and neuropsychology of comorbidity between RD and ADHD: the case for multiple-deficit models. Cortex 2010; 46:1345-61. [PMID: 20828676 PMCID: PMC2993430 DOI: 10.1016/j.cortex.2010.06.009] [Citation(s) in RCA: 234] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 03/18/2010] [Accepted: 04/28/2010] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Attention-deficit/hyperactivity disorder (ADHD) and reading disability (RD) are complex childhood disorders that frequently co-occur, but the etiology of this comorbidity remains unknown. METHOD Participants were 457 twin pairs from the Colorado Learning Disabilities Research Center (CLDRC) twin study, an ongoing study of the etiology of RD, ADHD, and related disorders. Phenotypic analyses compared groups with and without RD and ADHD on composite measures of six cognitive domains. Twin analyses were then used to test the etiology of the relations between the disorders and any cognitive weaknesses. RESULTS Phenotypic analyses supported the hypothesis that both RD and ADHD arise from multiple cognitive deficits rather than a single primary cognitive deficit. RD was associated independently with weaknesses on measures of phoneme awareness, verbal reasoning, and working memory, whereas ADHD was independently associated with a heritable weakness in inhibitory control. RD and ADHD share a common cognitive deficit in processing speed, and twin analyses indicated that this shared weakness is primarily due to common genetic influences that increase susceptibility to both disorders. CONCLUSIONS Individual differences in processing speed are influenced by genes that also increase risk for RD, ADHD, and their comorbidity. These results suggest that processing speed measures may be useful for future molecular genetic studies of the etiology of comorbidity between RD and ADHD.
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Affiliation(s)
- Erik G Willcutt
- Department of Psychology, University of Colorado, Boulder, CO 80309, USA.
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Understanding the complex etiologies of developmental disorders: behavioral and molecular genetic approaches. J Dev Behav Pediatr 2010; 31:533-44. [PMID: 20814254 PMCID: PMC2953861 DOI: 10.1097/dbp.0b013e3181ef42a1] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE This article has 2 primary goals. First, a brief tutorial on behavioral and molecular genetic methods is provided for readers without extensive training in these areas. To illustrate the application of these approaches to developmental disorders, etiologically informative studies of reading disability (RD), math disability (MD), and attention-deficit hyperactivity disorder (ADHD) are then reviewed. Implications of the results for these specific disorders and for developmental disabilities as a whole are discussed, and novel directions for future research are highlighted. METHOD Previous family and twin studies of RD, MD, and ADHD are reviewed systematically, and the extensive molecular genetic literatures on each disorder are summarized. To illustrate 4 novel extensions of these etiologically informative approaches, new data are presented from the Colorado Learning Disabilities Research Center, an ongoing twin study of the etiology of RD, ADHD, MD, and related disorders. CONCLUSIONS RD, MD, and ADHD are familial and heritable, and co-occur more frequently than expected by chance. Molecular genetic studies suggest that all 3 disorders have complex etiologies, with multiple genetic and environmental risk factors each contributing to overall risk for each disorder. Neuropsychological analyses indicate that the 3 disorders are each associated with multiple neuropsychological weaknesses, and initial evidence suggests that comorbidity between the 3 disorders is due to common genetic risk factors that lead to slow processing speed.
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Differential genetic etiology of reading difficulties as a function of IQ: an update. Behav Genet 2010; 40:751-8. [PMID: 20333543 DOI: 10.1007/s10519-010-9349-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 02/23/2010] [Indexed: 11/27/2022]
Abstract
In order to test the hypothesis that the genetic etiology of reading disability differs as a function of IQ, composite reading performance data from 308 pairs of identical (monozygotic, MZ) twins and 440 pairs of fraternal (dizygotic, DZ) twins (254 same-sex and 186 opposite-sex) in which at least one member of each pair was classified as reading-disabled were subjected to multiple regression analysis (DeFries and Fulker, Behav Genet 15:467-473, 1985; Acta Genet Med Gemellol 37:205-216, 1988). In the total sample, heritability of the group deficit in reading performance (h(g)(2)) was .61 (±.06). However, results of fitting an extended regression model to reading performance and IQ data suggested that the genetic etiology of reading disability differs as a linear function of IQ (p ≤ .04). When the basic regression model was fitted separately to data from twin pairs with Wechsler (Examiner's manual: Wechsler intelligence scale for children-revised, 1974; Examiner's manual: Wechsler adult intelligence scale-revised, 1981) Full Scale IQ scores in the upper and lower 25% of the sample, resulting estimates of h(g)(2) were .75 (±.12) and .50 (±.10), respectively (p ≤ .045). These results suggest that reading difficulties in children with a higher IQ are due substantially to genetic influences and may require intensive remediation efforts.
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Ludwig KU, Roeske D, Herms S, Schumacher J, Warnke A, Plume E, Neuhoff N, Bruder J, Remschmidt H, Schulte-Körne G, Müller-Myhsok B, Nöthen MM, Hoffmann P. Variation in GRIN2B contributes to weak performance in verbal short-term memory in children with dyslexia. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:503-511. [PMID: 19591125 DOI: 10.1002/ajmg.b.31007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A multi-marker haplotype within GRIN2B, a gene coding for a subunit of the ionotropic glutamate receptor, has recently been found to be associated with variation in human memory performance [de Quervain and Papassotiropoulos, 2006]. The gene locus is located within a region that has been linked to a phonological memory phenotype in a recent genome scan in families with dyslexia [Brkanac et al., 2008]. These findings may indicate the involvement of GRIN2B in memory-related aspects of human cognition. Memory performance is one of the cognitive functions observed to be disordered in dyslexia patients. We therefore investigated whether genetic variation in GRIN2B contributes to specific quantitative measures in a German dyslexia sample by genotyping 66 SNPs in its entire genomic region. We found supportive evidence that markers in intron 3 are associated with short-term memory in dyslexia, and were able to demonstrate that this effect is even stronger when only maternal transmission is considered. These results suggest that variation within GRIN2B may contribute to the genetic background of specific cognitive processes which are correlates of the dyslexia phenotype.
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Affiliation(s)
- Kerstin U Ludwig
- Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany.,Institute of Human Genetics, University of Bonn, Bonn, Germany
| | | | - Stefan Herms
- Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany.,Institute of Human Genetics, University of Bonn, Bonn, Germany
| | | | - Andreas Warnke
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Ellen Plume
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Nina Neuhoff
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Munich, Munich, Germany
| | - Jennifer Bruder
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Munich, Munich, Germany
| | - Helmut Remschmidt
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Marburg, Marburg, Germany
| | - Gerd Schulte-Körne
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Munich, Munich, Germany
| | | | - Markus M Nöthen
- Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany.,Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Per Hoffmann
- Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany.,Institute of Human Genetics, University of Bonn, Bonn, Germany
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Edvinsson D, Bingefors K, Lindström E, Lewander T. ADHD-related symptoms among adults in out-patient psychiatry and female prison inmates as compared with the general population. Ups J Med Sci 2010; 115:30-40. [PMID: 20085506 PMCID: PMC2853352 DOI: 10.3109/03009730903532333] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To compare the prevalence of symptoms consistent with attention deficit hyperactivity disorder (ADHD) and related problems in adults in the general population, out-patient psychiatry (where females are in majority), and female convicts. METHOD A questionnaire based on the DSM-IV criteria of ADHD, reported childhood symptoms, reading and spelling problems, difficulties and suffering, and general assessment of functioning (GAF) was distributed to samples of the general population, open care psychiatry, and female prison inmates. Completed questionnaires were received from 517/1000, 349/400, and 50/65 of the three samples, respectively. RESULTS Symptoms consistent with ADHD were more than three times higher in out-patient psychiatry than in the general population (6.6% versus 2.1%), with a male-to-female ratio of 1.6-1.7. The severity of symptoms and frequencies of associated disabilities were similar in men and women. ADHD symptoms and related problems occurred in 50% of the female prisoners, which is similar to male prisoners according to the literature. CONCLUSION The high prevalence of symptoms and disabilities of ADHD in women should lead to awareness of the disorder in both sexes and be addressed in terms of diagnostic work-up, treatment, and rehabilitation.
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Affiliation(s)
- Dan Edvinsson
- Department of Neuroscience/Psychiatry Ulleråker, Uppsala University Hospital, UppsalaSweden
| | | | - Eva Lindström
- Department of Pharmacy, Uppsala University, UppsalaSweden
| | - Tommy Lewander
- Department of Neuroscience/Psychiatry Ulleråker, Uppsala University Hospital, UppsalaSweden
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Lamminmäki T, Ahonen T, Närhi V, Lyytinen H, de Barra HT. Attention deficit hyperactivity disorder subtypes: Are there differences in academic problems? Dev Neuropsychol 2009. [DOI: 10.1080/87565649509540621] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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22
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Light JG, Pennington BF, Gilger JW, DeFries JC. Reading disability and hyperactivity disorder: Evidence for a common genetic etiology. Dev Neuropsychol 2009. [DOI: 10.1080/87565649509540623] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Couto JM, Gomez L, Wigg K, Ickowicz A, Pathare T, Malone M, Kennedy JL, Schachar R, Barr CL. Association of attention-deficit/hyperactivity disorder with a candidate region for reading disabilities on chromosome 6p. Biol Psychiatry 2009; 66:368-75. [PMID: 19362708 PMCID: PMC5750043 DOI: 10.1016/j.biopsych.2009.02.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 01/30/2009] [Accepted: 02/22/2009] [Indexed: 11/24/2022]
Abstract
BACKGROUND Reading disabilities (RD) and attention-deficit hyperactivity/disorder (ADHD) are two common childhood disorders that co-occur by chance more often than expected. Twin studies and overlapping genetic linkage findings indicate that shared genetic factors partially contribute to this comorbidity. Linkage of ADHD to 6p, an identified RD candidate locus, has previously been reported, suggesting the possibility of a pleiotropic gene at this locus. RD has been previously associated with five genes in the region, particularly DCDC2 and KIAA0319. METHODS To test whether these genes also contribute to ADHD, we investigated markers previously associated with RD for association with ADHD and ADHD symptoms in a sample of families with ADHD (n = 264). Markers were located in two subregions, VMP/DCDC2 and KIAA0319/TTRAP. RESULTS Across all analyses conducted, strong evidence for association was observed in the VMP/DCDC2 region. Association was equally strong with symptoms of both inattention and hyperactivity/impulsivity, suggesting that this locus contributes to both symptom dimensions. Markers were also tested for association with measures of reading skills (word identification, decoding); however, there was virtually no overlap in the markers associated with ADHD and those associated with reading skills in this sample. CONCLUSIONS Overall this study supports a previous linkage study of ADHD indicating a risk gene for ADHD on 6p and points to VMP or DCDC2 as the most likely candidates.
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Aureli A, Sebastiani P, Del Beato T, Marimpietri A, Melillo V, Sechi E, Di Loreto S. Investigation on the possible relationship existing between the HLA-DR gene and attention deficit hyperactivity disorder and/or mental retardation. Int J Immunopathol Pharmacol 2009; 21:985-91. [PMID: 19144284 DOI: 10.1177/039463200802100423] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study examines the possible relationship existing between the HLA-DR gene and attention deficit hyperactivity disorder (ADHD) and/or mental retardation (MR). The diagnosis of ADHD and mental retardation were established through clinical interviews with the parents, children and teachers, according to the criteria in DSM-IV. HLA-DRB1 genotyping was performed both by polymerase chain reaction-sequence specific primers (PCR-SSP) and by sequence based typing (SBT) in a cohort of 81 affected children and a sample of 100 healthy controls. Here, we report a positive association of HLA-DR4 with ADHD but not with MR. The study adds confirmation to the role of the HLA-DRB1 in the etiology of some types of childhood neuropsychiatric illnesses.
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Affiliation(s)
- A Aureli
- CNR ITOI Institute for Organ Transplantation and Immunocytology, L'Aquila, Italy
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Petrill SA, Saudino K, Cherny SS, Emde RN, Fulker DW, Hewitt JK, Plomin R. Exploring the Genetic and Environmental Etiology of High General Cognitive Ability in Fourteen- to Thirty-Six-Month-Old Twins. Child Dev 2008. [DOI: 10.1111/j.1467-8624.1998.tb06133.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ronald A, Simonoff E, Kuntsi J, Asherson P, Plomin R. Evidence for overlapping genetic influences on autistic and ADHD behaviours in a community twin sample. J Child Psychol Psychiatry 2008; 49:535-42. [PMID: 18221348 DOI: 10.1111/j.1469-7610.2007.01857.x] [Citation(s) in RCA: 291] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND High levels of clinical comorbidity have been reported between autistic spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD). This study takes an individual differences approach to determine the degree of phenotypic and aetiological overlap between autistic traits and ADHD behaviours in the general population. METHODS The Twins Early Development Study is a community sample born in England and Wales. Families with twins born in 1994-6 were invited to join; 6,771 families participated in the study when the twins were 8 years old. Parents completed the Childhood Asperger Syndrome Test and the Conners' DSM-IV subscales. Teacher data were also collected on a sub-sample. High scores on the Conners' subscales were used to identify possible ADHD cases. Potential ASD cases were interviewed using the Development and Well-Being Assessment. Multivariate structural equation model-fitting was employed, as well as DeFries Fulker extremes analysis and liability threshold model-fitting. RESULTS Significant correlations were found between autistic and ADHD traits in the general population (.54 for parent data, .51 for teacher data). In the bivariate models, all genetic correlations were >.50, indicating a moderate degree of overlap in genetic influences on autistic and ADHD traits, both throughout the general population and at the quantitative extreme. This phenotypic and genetic overlap still held when sex, IQ and conduct problems were controlled for, for both parent and teacher data. There was also substantial overlap in suspected cases (41% of children who met criteria for an ASD had suspected ADHD; 22% with suspected ADHD met criteria for an ASD). CONCLUSIONS These results suggest there are some common genetic influences operating across autistic traits and ADHD behaviours throughout normal variation and at the extreme. This is relevant for molecular genetic research, as well as for psychiatrists and psychologists, who may have assumed these two sets of behaviours are independent.
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Affiliation(s)
- Angelica Ronald
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, London, UK.
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Mayes SD, Calhoun SL. Learning, attention, writing, and processing speed in typical children and children with ADHD, autism, anxiety, depression, and oppositional-defiant disorder. Child Neuropsychol 2008; 13:469-93. [PMID: 17852125 DOI: 10.1080/09297040601112773] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Learning, attention, graphomotor, and processing speed scores were analyzed in 149 typical control children and 886 clinical children with normal intelligence. Nonsignificant differences were found between control children and children with anxiety, depression, and oppositional-defiant disorder. Control children performed better than children with ADHD and autism in all areas. Children with ADHD and autism did not differ, except that children with ADHD had greater learning problems. Attention, graphomotor, and speed weaknesses were likely to coexist, the majority of children with autism and ADHD had weaknesses in all three areas, and these scores contributed significantly to the prediction of academic achievement.
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Affiliation(s)
- Susan Dickerson Mayes
- Department of Psychiatry, Milton S. Hershey Medical Center, Penn State College of Medicine, Hershey, PA 17033, USA.
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Dworzynski K, Ronald A, Hayiou-Thomas ME, McEwan F, Happé F, Bolton P, Plomin R. Developmental path between language and autistic-like impairments: a twin study. INFANT AND CHILD DEVELOPMENT 2008. [DOI: 10.1002/icd.536] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Viding E, Jones AP, Paul JF, Moffitt TE, Plomin R. Heritability of antisocial behaviour at 9: do callous-unemotional traits matter? Dev Sci 2008; 11:17-22. [DOI: 10.1111/j.1467-7687.2007.00648.x] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gene × Environment interactions in speech sound disorder predict language and preliteracy outcomes. Dev Psychopathol 2007; 19:1047-72. [PMID: 17931434 DOI: 10.1017/s0954579407000533] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractFew studies have investigated the role of gene × environment interactions (G × E) in speech, language, and literacy disorders. Currently, there are two theoretical models, the diathesis–stress model and the bioecological model, that make opposite predictions about the expected direction of G × E, because environmental risk factors may either strengthen or weaken the effect of genes on phenotypes. The purpose of the current study was to test for G × E at two speech sound disorder and reading disability linkage peaks using a sib-pair linkage design and continuous measures of socioeconomic status, home language/literacy environment, and number of ear infections. The interactions were tested using composite speech, language, and preliteracy phenotypes and previously identified linkage peaks on 6p22 and 15q21. Results showed five G × E at both the 6p22 and 15q21 locations across several phenotypes and environmental measures. Four of the five interactions were consistent with the bioecological model of G × E. Each of these four interactions involved environmental measures of the home language/literacy environment. The only interaction that was consistent with the diathesis–stress model was one involving the number of ear infections as the environmental risk variable. The direction of these interactions and possible interpretations are explored in the discussion.
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Willcutt EG, Pennington BF, Olson RK, DeFries JC. Understanding comorbidity: a twin study of reading disability and attention-deficit/hyperactivity disorder. Am J Med Genet B Neuropsychiatr Genet 2007; 144B:709-14. [PMID: 17440942 DOI: 10.1002/ajmg.b.30310] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A community sample of twins in which at least one member of each pair exhibited significant reading difficulties (99 monozygotic and 80 dizygotic pairs) or symptoms of attention-deficit/hyperactivity disorder (ADHD; 83 monozygotic and 78 dizygotic pairs) was used to test the etiology of comorbidity between reading disability (RD) and ADHD. Univariate analyses revealed moderate to high heritability for all measures of reading difficulty and ADHD. Subsequent bivariate analyses indicated that the relation between reading difficulties and inattention symptoms is primarily attributable to common genetic influences, whereas bivariate heritability estimates were not significant for hyperactivity-impulsivity and any of the reading measures. Reading difficulties and ADHD symptoms were more highly heritable if the proband met criteria for both disorders versus RD or ADHD alone, suggesting that future molecular genetic analyses of comorbid RD + ADHD may facilitate the identification of susceptibility genes for RD, ADHD, and their comorbidity.
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Affiliation(s)
- Erik G Willcutt
- University of Colorado at Boulder, Boulder, Colorado 80309, USA.
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Simonoff E, Pickles A, Wood N, Gringras P, Chadwick O. ADHD symptoms in children with mild intellectual disability. J Am Acad Child Adolesc Psychiatry 2007; 46:591-600. [PMID: 17450050 DOI: 10.1097/chi.0b013e3180323330] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To determine whether the nature and correlates of attention-deficit/hyperactivity disorder (ADHD) symptoms are different in subjects with mild intellectual disability (ID) compared to subjects with average ability. METHOD From a general population sample of 2,726 12- to 15-year-olds, a stratified subsample was selected to enrich for mild ID. A total of 192 subjects were included in the analyses. ADHD symptoms and other emotional/behavioral problems were measured with the parent and teacher Strengths and Difficulties Questionnaire and IQ with the WISC-III-UK), and social communication difficulties were assessed by a short version of the Social Communication Questionnaire and academic attainments by the Wechsler Quicktest. RESULTS There was a negative linear relationship between ADHD symptoms and IQ (beta = -.087, p <.001). The relationship could not be explained by inappropriate rater expectations. Neither the profiles of ADHD symptoms nor the comorbidity with emotional/behavioral problems differed according to the presence of ID. When IQ was accounted for, the group difference in attainments was nonsignificant. CONCLUSIONS ADHD symptoms are increased in people with ID. We found no evidence that this increase can by explained by inappropriate expectations or by confounding associations with other emotional/behavioral or cognitive problems.
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Affiliation(s)
- Emily Simonoff
- Dr. Simonoff and Ms. Wood are with the Department of Child and Adolescent Psychiatry, King's College London, Institute of Psychiatry, London; Dr. Pickles is with the Biostatistics Group, Division of Epidemiology and Health Science, University of Manchester, Manchester, UK; Dr. Gringras is with Guy's and St. Thomas' Hospitals NHS Trust, London; and Dr. Chadwick is with the Department of Psychology, King's College London, Institute of Psychiatry, London.
| | - Andrew Pickles
- Dr. Simonoff and Ms. Wood are with the Department of Child and Adolescent Psychiatry, King's College London, Institute of Psychiatry, London; Dr. Pickles is with the Biostatistics Group, Division of Epidemiology and Health Science, University of Manchester, Manchester, UK; Dr. Gringras is with Guy's and St. Thomas' Hospitals NHS Trust, London; and Dr. Chadwick is with the Department of Psychology, King's College London, Institute of Psychiatry, London
| | - Nicky Wood
- Dr. Simonoff and Ms. Wood are with the Department of Child and Adolescent Psychiatry, King's College London, Institute of Psychiatry, London; Dr. Pickles is with the Biostatistics Group, Division of Epidemiology and Health Science, University of Manchester, Manchester, UK; Dr. Gringras is with Guy's and St. Thomas' Hospitals NHS Trust, London; and Dr. Chadwick is with the Department of Psychology, King's College London, Institute of Psychiatry, London
| | - Paul Gringras
- Dr. Simonoff and Ms. Wood are with the Department of Child and Adolescent Psychiatry, King's College London, Institute of Psychiatry, London; Dr. Pickles is with the Biostatistics Group, Division of Epidemiology and Health Science, University of Manchester, Manchester, UK; Dr. Gringras is with Guy's and St. Thomas' Hospitals NHS Trust, London; and Dr. Chadwick is with the Department of Psychology, King's College London, Institute of Psychiatry, London
| | - Oliver Chadwick
- Dr. Simonoff and Ms. Wood are with the Department of Child and Adolescent Psychiatry, King's College London, Institute of Psychiatry, London; Dr. Pickles is with the Biostatistics Group, Division of Epidemiology and Health Science, University of Manchester, Manchester, UK; Dr. Gringras is with Guy's and St. Thomas' Hospitals NHS Trust, London; and Dr. Chadwick is with the Department of Psychology, King's College London, Institute of Psychiatry, London
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Schulte-Körne G, Warnke A, Remschmidt H. Zur Genetik der Lese-Rechtschreibschwäche. ZEITSCHRIFT FUR KINDER-UND JUGENDPSYCHIATRIE UND PSYCHOTHERAPIE 2006; 34:435-44. [PMID: 17094062 DOI: 10.1024/1422-4917.34.6.435] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Zusammenfassung: Die Lese-Rechtschreibstörung (LRS) ist eine der häufigsten Entwicklungsstörungen. Die Ursachen dieser komplexen Störung sind bisher nur kaum verstanden. Familienuntersuchungen zeigen, dass die LRS familiär gehäuft auftritt und dass das Risiko für ein Geschwisterkind, eine LRS zu entwickeln, ca. 3,5fach erhöht ist. Verschiedene kognitive Fähigkeiten sind mit der LRS korreliert. Hierzu gehören die phonologische Bewusstheit, orthographisches Wissen, phonologisches Dekodieren, auditives Kurzzeitgedächtnis und schnelles Benennen. Eine familiäre Häufung dieser mit der LRS korrelierten Dimensionen und eine hohe Erblichkeit (Heritabilität) wurden wiederholt gefunden. Die Heritabilität für die Lesefähigkeit liegt zwischen 50-60%, für die Rechtschreibstörung zwischen 50 und 70%. Durch genomweite Kopplungsuntersuchungen wurden bisher 9 Kandidatengenregionen (DYX1-9) identifiziert. Vier Kandidatengene, DCDC2, KIAA0319, ROBO1 und DYX1C1 wurden kürzlich beschrieben. Diese beeinflussen die neuronale Migration und sind daher funktionell aussichtsreiche Kandidatengene für die LRS. Allerdings konnte bisher keine funktionell relevante Mutation gefunden werden. Die Komorbidität zwischen LRS und ADHD sowie LRS und Sprachentwicklungsstörungen könnte zum Teil durch gemeinsame genetische Faktoren erklärt werden. In der Zukunft wird es für die Ursachenforschung der LRS entscheidend sein, möglichst alle ursachenrelevanten Dimensionen gemeinsam an ausreichend großen Stichproben zu untersuchen. Neben den relevanten neurobiologischen Faktoren sollten auch Umweltfaktoren und die verschiedenen Interaktionen, wie z.B. Gen-Umwelt und Gen-Gen-Interaktionen untersucht werden. In einem europäischen, kollaborativen Forschungsvorhaben (NeuroDys) wird weltweit die größte Stichprobe von Kindern mit einer LRS gesammelt und untersucht, um durch ein verbessertes Ursachenverständnis unter Einschluss der Identifikation von genetischen Risikofaktoren die Komplexität des Störungsbildes besser zu verstehen und perspektivisch spezifische Therapien zu entwickeln.
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Affiliation(s)
- Gerd Schulte-Körne
- 1 Klinik für Kinder- und Jugendpsychiatrie, Psychosomatik und Psychotherapie, Klinikum der Universität München, Pettenkoferstrasse 8a, DE-80336 München
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Ronald A, Happé F, Price TS, Baron-Cohen S, Plomin R. Phenotypic and genetic overlap between autistic traits at the extremes of the general population. J Am Acad Child Adolesc Psychiatry 2006; 45:1206-1214. [PMID: 17003666 DOI: 10.1097/01.chi.0000230165.54117.41] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To investigate children selected from a community sample for showing extreme autistic-like traits and to assess the degree to which these individual traits--social impairments (SIs), communication impairments (CIs), and restricted repetitive behaviors and interests (RRBIs)--are caused by genes and environments, whether all of them are caused by the same genes and environments, and how often they occur together (as required by an autism diagnosis). METHOD The most extreme-scoring 5% were selected from 3,419 8-year-old pairs in the Twins Early Development Study assessed on the Childhood Asperger Syndrome Test. Phenotypic associations between extreme traits were compared with associations among the full-scale scores. Genetic associations between extreme traits were quantified using bivariate DeFries-Fulker extremes analysis. RESULTS Phenotypic relationships between extreme SIs, CIs, and RRBIs were modest. There was a degree of genetic overlap between them, but also substantial genetic specificity. CONCLUSIONS This first twin study assessing the links between extreme individual autistic-like traits (SIs, CIs, and RRBIs) found that all are highly heritable but show modest phenotypic and genetic overlap. This finding concurs with that of an earlier study from the same cohort that showed that a total autistic symptoms score at the extreme showed high heritability and that SIs, CIs, and RRBIs show weak links in the general population. This new finding has relevance for both clinical models and future molecular genetic studies.
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Affiliation(s)
- Angelica Ronald
- Drs. Ronald, Happé, and Plomin are with the Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London; Dr. Price is with the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia; and Dr. Baron-Cohen is with the Autism Research Centre, Cambridge University, Cambridge, UK.
| | - Francesca Happé
- Drs. Ronald, Happé, and Plomin are with the Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London; Dr. Price is with the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia; and Dr. Baron-Cohen is with the Autism Research Centre, Cambridge University, Cambridge, UK
| | - Thomas S Price
- Drs. Ronald, Happé, and Plomin are with the Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London; Dr. Price is with the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia; and Dr. Baron-Cohen is with the Autism Research Centre, Cambridge University, Cambridge, UK
| | - Simon Baron-Cohen
- Drs. Ronald, Happé, and Plomin are with the Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London; Dr. Price is with the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia; and Dr. Baron-Cohen is with the Autism Research Centre, Cambridge University, Cambridge, UK
| | - Robert Plomin
- Drs. Ronald, Happé, and Plomin are with the Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London; Dr. Price is with the Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia; and Dr. Baron-Cohen is with the Autism Research Centre, Cambridge University, Cambridge, UK
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Abstract
Wechsler Intelligence Scale for Children, 3rd and 4th editions (WISC-III n = 586 and WISC-IV n = 118), profiles were compared for children with ADHD and normal intelligence. Mean Verbal Comprehension Index (VCI) and Perceptual Organization/Perceptual Reasoning Index (POI/PRI) scores were significantly higher than Freedom From Distractibility/Working Memory Index (FDI/WMI) and Processing Speed Index (PSI), and Symbol Search was higher than Coding. FDI/WMI and PSI scores were similar on both tests, but VCI and POI/PRI were higher on the WISC-IV than on the WISC-III. Therefore, index discrepancies were greater for the WISC-IV, suggesting that the WISC-IV might be better than the WISC-III in delineating the strengths and weaknesses of children with ADHD. All children in the WISC-IV sample scored lowest on WMI or PSI, whereas only 88% of the WISC-III children scored lowest on FDI or PSI. Thus, the WISC-IV may be more helpful in diagnosing ADHD than the WISC-III.
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Filippatou DN, Livaniou EA. Comorbidity and WISC-III profiles of Greek children with attention deficit hyperactivity disorder, learning disabilities, and language disorders. Psychol Rep 2006; 97:485-504. [PMID: 16342577 DOI: 10.2466/pr0.97.2.485-504] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of the present study was to (a) examine the prevalence of ADHD and the comorbid difficulties in a sample of 114 children, 3.6 to 17.6 yr. of age (89 boys, 25 girls) referred to our Unit and (b) evaluate the discriminative ability of the WISC-III scores for children with Attention Deficit Hyperactivity Disorder (n = 22), Learning Disability (n = 50), and Language Disorder (n = 42). Analysis showed only 18% of 114 children had an Attention Deficit Hyperactivity Disorder diagnosis. Multivariate analysis of variance and stepwise discriminant function analysis were applied. Vocabulary and similarities were the best predictors for distinguishing between language disorders and the other two groups. Moreover, the Language Disorder group scored significantly lower on all the subtests while the Attention Deficit Hyperactivity Disorder and Learning Disability groups scored lower on coding and information, respectively. Children with Attention Deficit Hyperactivity Disorder and Learning Disability could not be accurately identified from the WISC-III test or their ACID profile.
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Affiliation(s)
- Diamanto N Filippatou
- Special Diagnostic, Research and Therapeutic Unit "Spyros Doxiadis", Athens, Greece.
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Frequency of reading, math, and writing disabilities in children with clinical disorders. LEARNING AND INDIVIDUAL DIFFERENCES 2006. [DOI: 10.1016/j.lindif.2005.07.004] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Pennington BF, Willcutt E, Rhee SH. Analyzing comorbidity. ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR 2005; 33:263-304. [PMID: 16101120 DOI: 10.1016/s0065-2407(05)80010-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Stevenson J, Langley K, Pay H, Payton A, Worthington J, Ollier W, Thapar A. Attention deficit hyperactivity disorder with reading disabilities: preliminary genetic findings on the involvement of the ADRA2A gene. J Child Psychol Psychiatry 2005; 46:1081-8. [PMID: 16178932 DOI: 10.1111/j.1469-7610.2005.01533.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Attention deficit/hyperactivity disorder (ADHD) and reading disability (RD) tend to co-occur and quantitative genetic studies have shown this to arise primarily through shared genetic influences. However, molecular genetic studies have shown different genes to be associated with each of these conditions. Neurobiological studies have implicated noradrenergic function in the aetiology of ADHD that is comorbid with RD. This paper examines the neurobiological evidence and presents preliminary testing of the hypothesis that the ADRA2A receptor gene is contributing to ADHD and comorbid RD. METHODS One hundred and fifty-two children (140 boys, 12 girls) of British Caucasian origin, aged between 6 and 13 years and with a diagnosis of ADHD, were recruited. The children's reading ability was tested. Children were identified as having ADHD or ADHD plus RD (n=82). DNA was available for 110 parent child trios and 42 parent child duos. Genotyping was undertaken for an ADRA2A polymorphism. RESULTS For those with ADHD plus RD there was evidence of association with the alpha 2A adrenergic receptor (ADRA2A) polymorphism with the G allele being preferentially transmitted. CONCLUSIONS The preliminary evidence together with other neurobiological research findings suggests that the ADRA2A gene may contribute to comorbid ADHD and RD and needs to be properly examined.
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Affiliation(s)
- J Stevenson
- School of Psychology, University of Southampton, UK
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DeThorne LS, Petrill SA, Hayiou-Thomas ME, Plomin R. Low expressive vocabulary: higher heritability as a function of more severe cases. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2005; 48:792-804. [PMID: 16378474 DOI: 10.1044/1092-4388(2005/055)] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2004] [Revised: 08/23/2004] [Accepted: 09/28/2004] [Indexed: 05/05/2023]
Abstract
This study of 4,274 pairs of 4-year-old twins from the Twins Early Development Study explored the magnitude of genetic and environmental effects on low expressive vocabulary skill, both as a function of general cognitive ability and as a function of the severity of expressive vocabulary impairment. Assessments were conducted through parent report measures. Two types of vocabulary deficit were identified: low vocabulary paired with typical general cognition (i.e., specific expressive vocabulary impairment) and low vocabulary paired with low general cognition (i.e., nonspecific expressive vocabulary impairment). The magnitude of genetic and environmental effects on low expressive vocabulary skill did not differ for these 2 types of expressive vocabulary deficit. By systematically varying the cutoffs used to define vocabulary and general cognitive delay, potential changes in the magnitude of genetic and environmental effects were examined. Results suggested that the severity of vocabulary deficit rather than level of cognitive functioning was a more meaningful etiological distinction: The heritability of low expressive vocabulary was higher and the influence of shared environment lower, as increasingly severe vocabulary deficits were identified. Implications for molecular genetics and the construct of specific language deficits are discussed.
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Stevenson J, Asherson P, Hay D, Levy F, Swanson J, Thapar A, Willcutt E. Characterizing the ADHD phenotype for genetic studies. Dev Sci 2005; 8:115-21. [PMID: 15720369 DOI: 10.1111/j.1467-7687.2005.00398.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The genetic study of ADHD has made considerable progress. Further developments in the field will be reliant in part on identifying the most appropriate phenotypes for genetic analysis. The use of both categorical and dimensional measures of symptoms related to ADHD has been productive. The use of multiple reporters is a valuable feature of the characterization of psychopathology in children. It is argued that the use of aggregated measures to characterize the ADHD phenotype, particularly to establish its pervasiveness, is desirable. The recognition of the multiple comorbidities of ADHD can help to isolate more specific genetic influences. In relation to both reading disability and conduct disorder there is evidence that genes may be involved in the comorbid condition that are different from pure ADHD. To date, progress with the investigation of endophenotypes for ADHD has been disappointing. It is suggested that extending such studies beyond cognitive underpinnings to include physiological and metabolic markers might facilitate progress.
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Affiliation(s)
- Jim Stevenson
- School of Psychology, University of Southampton, Highfield, Southampton SO17 1 BJ, UK.
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Abstract
BACKGROUND Individuals with early warning signs of life-long psychopathy, callous-unemotional traits (CU) and high levels of antisocial behaviour (AB) can be identified in childhood. We report here the first twin study of high levels of psychopathic tendencies in young children. METHODS At the end of the first school year, teachers provided ratings of CU and AB for 3687 twin pairs from the Twins Early Development Study (TEDS). For the analyses of extreme CU, we selected same-sex twin pairs where at least one twin scored 1.3 or more standard deviations above the mean on the CU scale (612 probands, 459 twin pairs). For the analysis of extreme AB, we selected same-sex twin pairs where at least one twin scored 1.3 or more standard deviations above the mean on AB scale (444 probands, 364 twin pairs). Furthermore, the extreme AB sample was divided into those who were also extreme on CU (children with psychopathic tendencies; 234 probands, 187 twin pairs) and those who did not score in the extreme for CU (children without psychopathic tendencies; 210 probands, 177 twin pairs). RESULTS DeFries-Fulker extremes analysis indicated that exhibiting high levels of CU is under strong genetic influence. Furthermore, separating children with AB into those with high and low levels of CU showed striking results: AB in children with high levels of CU is under extremely strong genetic influence and no influence of shared environment, whereas AB in children with low levels of CU shows moderate genetic and shared environmental influence. CONCLUSIONS The remarkably high heritability for CU, and for AB children with CU, suggests that molecular genetic research on antisocial behaviour should focus on the CU core of psychopathy. Our findings also raise questions for public policy on interventions for antisocial behaviour.
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Affiliation(s)
- Essi Viding
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, London, UK.
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Hayiou-Thomas ME, Oliver B, Plomin R. Genetic influences on specific versus nonspecific language impairment in 4-year-old twins. JOURNAL OF LEARNING DISABILITIES 2005; 38:222-32. [PMID: 15940960 DOI: 10.1177/00222194050380030401] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The present study addresses the distinction between specific (SLI) and nonspecific (NLI) language impairment at an etiological level by estimating the relative genetic and environmental contributions to language impairment in children with SLI and NLI. Drawing on a large longitudinal twin study, we tested a sample of 356 four-and-a-half-year-old children with low language ability and their twin partners at home on a range of language and nonverbal measures. For children whose language and nonverbal abilities were both low (NLI), genetic influence on language impairment was moderate and shared environmental influence was substantial. A similar pattern emerged for children whose language difficulties occurred in apparent isolation (SLI), although there was a trend for the genetic effects to be smaller for SLI than for NLI: Group heritability was .18 for SLI and .52 for NLI. Probandwise cross-concordances were suggestive of some genetic overlap between these two groups, but not with a subgroup of children with more severe cognitive delay.
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Carroll JM, Maughan B, Goodman R, Meltzer H. Literacy difficulties and psychiatric disorders: evidence for comorbidity. J Child Psychol Psychiatry 2005; 46:524-32. [PMID: 15845132 DOI: 10.1111/j.1469-7610.2004.00366.x] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Literacy difficulties show high levels of comorbidity with both disruptive and emotional disorders, but questions remain over the nature and specificity of these links. METHOD Relationships between specific literacy difficulties and psychiatric disorder were investigated in a large-scale national sample of children aged 9 to 15 years. RESULTS Specific literacy difficulties were more common in children from lower socio-economic backgrounds, and were significantly associated with increased risks of Attention-Deficit Hyperactivity Disorder (especially inattentive symptomatology), Conduct Disorder and anxiety disorders in both girls and boys, and with self-reports of depressed mood in boys. Associations between literacy difficulties and diagnoses of both Attention-Deficit Hyperactivity Disorder (ADHD) and Conduct Disorder (CD) were mediated by inattentiveness, as were links with low mood. Links between specific literacy difficulties and anxiety were of a different nature, suggestive of a direct impact of literacy problems on risk for anxiety disorders. CONCLUSIONS Literacy difficulties are significantly associated with externalizing disorders via inattention, but may constitute a more immediate risk factor for naturally anxious children to develop clinically significant levels of anxiety.
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Harlaar N, Spinath FM, Dale PS, Plomin R. Genetic influences on early word recognition abilities and disabilities: a study of 7-year-old twins. J Child Psychol Psychiatry 2005; 46:373-84. [PMID: 15819646 DOI: 10.1111/j.1469-7610.2004.00358.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND A fundamental issue for child psychology concerns the origins of individual differences in early reading development. METHOD A measure of word recognition, the Test of Word Reading Efficiency (TOWRE), was administered by telephone to a representative population sample of 3,909 same-sex and opposite-sex pairs of 7-year-old twins. Analyses allowing for sex differences in aetiology were used to estimate the extent to which genetic and environmental influences contribute to normal variation in word recognition and word recognition difficulties, defined by scores below the 5th and 10th percentiles of the unselected sample. RESULTS Both normal variation in word recognition and impaired word recognition abilities were substantially heritable (h2 = .65-.67; h(g)2 = .37-.72). Environmental influences were primarily shared between twins, rather than specific to each individual, and small to moderate in magnitude. There was evidence for qualitative sex differences. Quantitative sex differences were also suggested at the extremes, with genetic influences being more important as a cause of reading difficulties in boys than in girls. CONCLUSIONS These findings indicate that early individual differences and impairments in word recognition are principally influenced by genetic factors and may involve partly distinct genetic or environmental effects in boys and girls. Crucially, they also provide evidence that reading impairments are linked genetically to the normal distribution. Genetic risk for early impairments in word recognition is continuous rather than discrete.
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Affiliation(s)
- Nicole Harlaar
- Social, Genetic, & Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, UK.
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Banaschewski T, Hollis C, Oosterlaan J, Roeyers H, Rubia K, Willcutt E, Taylor E. Towards an understanding of unique and shared pathways in the psychopathophysiology of ADHD. Dev Sci 2005; 8:132-40. [PMID: 15720371 DOI: 10.1111/j.1467-7687.2005.00400.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Most attention deficit hyperactivity disorder (ADHD) research has compared cases with unaffected controls. This has led to many associations, but uncertainties about their specificity to ADHD in contrast with other disorders. We present a selective review of research, comparing ADHD with other disorders in neuropsychological, neurobiological and genetic correlates. So far, a specific pathophysiological pathway has not been identified. ADHD is probably not specifically associated with executive function deficits. It is possible, but not yet established, that ADHD symptoms may be more specifically associated with motivational abnormalities, motor organization and time perception. Recent findings indicating common genetic liabilities of ADHD and other conditions raise questions about diagnostic boundaries. In future research, the delineation of the pathophysiological mechanisms of ADHD needs to match cognitive, imaging and genetic techniques to the challenge of defining more homogenous clinical groups; multi-site collaborative projects are needed.
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Affiliation(s)
- Tobias Banaschewski
- Child and Adolescent Psychiatry, University of Göttingen, von-Siebold-Str. 5, D-37075 Göttingen, Germany.
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Willcutt EG, Pennington BF, Olson RK, Chhabildas N, Hulslander J. Neuropsychological Analyses of Comorbidity Between Reading Disability and Attention Deficit Hyperactivity Disorder: In Search of the Common Deficit. Dev Neuropsychol 2005; 27:35-78. [PMID: 15737942 DOI: 10.1207/s15326942dn2701_3] [Citation(s) in RCA: 358] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Measures of component reading and language skills, executive functions, and processing speed were administered to groups of children with attention deficit hyperactivity disorder (ADHD; n = 113), reading disability (RD; n = 109), both RD and ADHD (n = 64), and neither RD nor ADHD (n = 151). Groups with RD exhibited pronounced deficits on all measures of component reading and language skills, as well as significant weaknesses on measures of verbal working memory, processing speed, and response inhibition. Groups with ADHD exhibited weaknesses on all response-inhibition and processing speed tasks and were impaired on some measures of component reading skills and verbal working memory. The group with comorbid RD and ADHD exhibited the combination of the deficits in the RD-only and ADHD-only groups, providing evidence against the phenocopy and cognitive subtype hypotheses as explanations for the co-occurrence of RD and ADHD. Slow and variable processing speed was characteristic of all 3 clinical groups, suggesting that measures of this domain may be useful for future studies that search for the common genes that increase susceptibility to RD and ADHD.
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Affiliation(s)
- Erik G Willcutt
- Department of Psychology, University of Colorado at Boulder, CO 80309, USA.
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FILIPPATOU DIAMANTON. COMORBIDITY AND WISC-III PROFILES OF GREEK CHILDREN WITH ATTENTION DEFICIT HYPERACTIVITY DISORDER, LEARNING DISABILITIES, AND LANGUAGE DISORDERS. Psychol Rep 2005. [DOI: 10.2466/pr0.97.6.485-504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Monuteaux MC, Faraone SV, Herzig K, Navsaria N, Biederman J. ADHD and dyscalculia: Evidence for independent familial transmission. JOURNAL OF LEARNING DISABILITIES 2005; 38:86-93. [PMID: 15727331 DOI: 10.1177/00222194050380010701] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The familial relationship between dyscalculia and attention-deficit/hyperactivity disorder (ADHD) was assessed. We conducted a familial risk analysis using probands with and without ADHD of both genders and their first-degree relatives. Participants were assessed with structured diagnostic interviews and a cognitive test battery. We found elevated rates of ADHD in relatives of both ADHD proband groups, regardless of dyscalculia status, and elevated rates of dyscalculia in relatives of probands with dyscalculia, irrespective of ADHD status. There was no evidence for cosegregation or assortative mating. Our findings support the hypothesis that ADHD and dyscalculia are independently transmitted in families and are etiologically distinct. These results reinforce the current nosological approach to these disorders and underscore the need for separate identification and treatment strategies for children with both conditions.
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Affiliation(s)
- Michael C Monuteaux
- Massachusetts General Hospital, Pediatric Psychopharmacology Program, Boston, 02114, USA
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50
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Abstract
BACKGROUND ADHD is a common and complex genetic disorder. Genetic risk factors are expected to be multiple, have small effect sizes when considered individually and to interact with each other and with environmental factors. OBJECTIVE To describe the difficulties involved in the genetic investigation of such a complex disorder and give a prospective for the future. METHODS Review based on empirical literature and project description. RESULTS Considerable progress has been achieved through the association analysis of candidate gene loci. Linkage scans using affected sibling pairs have identified a number of potential loci that may lead to the identification of novel genes of moderate effect size. Quantitative trait locus (QTL) approaches provide powerful complementary strategies that have the potential to link the categorical disorder to continuously distributed traits associated more closely with underlying genetic liability in the general population. Success in identifying some associated genes has been complemented by functional studies that seek to understand the mode of action of such genes. CONCLUSION Progress in understanding the mechanisms involved has not been straightforward and many inconsistencies have arisen. In order to take advantage of the potential for progress that stems from the genetic findings it will be important to draw upon a variety of approaches and experimental paradigms. A functional genomic approach to ADHD means that investigation of gene function is carried out at various levels of analysis, not only at the level of molecular and cellular function but also at the level of psychological processes, neuronal networks, environmental interactions and behavioural outcomes.
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Affiliation(s)
- Philip Asherson
- MRC Social Genetic Developmental, Psychiatry Research Centre, Institute of Psychiatry, Kings College London, de Crespigny Park, London SE5 8AF, UK.
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