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Schulz-Zhecheva Y, Voelkle MC, Beauducel A, Biscaldi M, Klein C. Intra-Subject Variability, Intelligence, and ADHD Traits in a Community-Based Sample. J Atten Disord 2023; 27:67-79. [PMID: 36082454 DOI: 10.1177/10870547221118523] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The present study investigates the predictive validity of intra-subject variability (ISV) for ADHD traits in a community-based sample and the stability of the relationship between ISV and fluid intelligence (gf) across the continuum of ADHD traits. METHOD Age-residualized data from 426 participants (8-18 years, 6% ADHD) was used to investigate whether ex-Gaussian and DDM parameters derived from simple choice-reaction-time tasks can predict continuously assessed ADHD traits. Multiple-Group-Analyses and Latent-Moderated-Structural-Equations were used to test whether ADHD traits moderate the relationship between ISV and gf. RESULTS σ and μ of the ex-Gaussian model as well as DDM parameters drift rate (v) and boundary separation (a) significantly predicted general ADHD traits, while τ predicted attention difficulties specifically. Across the ADHD continuum, σ and v were significant predictors of gf. CONCLUSION The results confirm the link between ISV and ADHD. The relationship between ISV and gf appears stable across the ADHD continuum.
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Affiliation(s)
| | | | | | | | - Christoph Klein
- University of Freiburg, Germany.,University of Cologne, Germany.,National and Kapodistrian University of Athens, Germany
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2
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Michelini G, Cheung CHM, Kitsune V, Brandeis D, Banaschewski T, McLoughlin G, Asherson P, Rijsdijk F, Kuntsi J. The Etiological Structure of Cognitive-Neurophysiological Impairments in ADHD in Adolescence and Young Adulthood. J Atten Disord 2021; 25:91-104. [PMID: 29720024 PMCID: PMC7750664 DOI: 10.1177/1087054718771191] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Objective: Previous studies in children with ADHD identified two partially separable familial factors underlying cognitive dysfunction, but evidence in adolescents and adults is lacking. Here, we investigate the etiological structure of cognitive-neurophysiological impairments in ADHD in adolescents and young adults. Method: Factor analyses and multivariate familial models were run in 356 participants from ADHD and control sibling pairs aged 11 to 27 years on data on IQ, digit span forward (DSF) and backward (DSB), and cognitive-performance and event-related potential (ERP) measures from three cognitive tasks. Results: Three familial factors (cF1-3), showing substantial familial overlap with ADHD, captured the familial covariation of ADHD with nine cognitive-ERP measures. cF1 loaded on IQ, mean reaction time (MRT), and reaction-time variability (RTV); cF2 on DSF and DSB; and cF3 on number of errors and ERPs of inhibition and error processing. Conclusion: These results identify three partially separable etiological pathways leading to cognitive-neurophysiological impairments in adolescent and adult ADHD.
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Affiliation(s)
| | | | | | - Daniel Brandeis
- Heidelberg University, Mannheim,
Germany,University of Zurich, Switzerland
| | | | | | | | | | - Jonna Kuntsi
- King’s College London, UK,Jonna Kuntsi, King’s College London, Social,
Genetic & Developmental Psychiatry Centre, Institute of Psychiatry,
Psychology & Neuroscience, 16 De Crespigny Park, London SE5 8AF, UK.
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3
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Karalunas SL, Bierman K, Huang-Pollock CL. Test-Retest Reliability and Measurement Invariance of Executive Function Tasks in Young Children With and Without ADHD. J Atten Disord 2020; 24:1891-1904. [PMID: 26861156 PMCID: PMC4980280 DOI: 10.1177/1087054715627488] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Objective: Measurement reliability is assumed when executive function (EF) tasks are used to compare groups or to examine relationships between cognition and etiologic and maintaining factors of psychiatric disorders. However, the test-retest reliabilities of many commonly used EF tasks have rarely been examined in young children. Furthermore, measurement invariance between typically developing and psychiatric populations has not been examined. Method: Test-retest reliability of a battery of commonly used EF tasks was assessed in a group of children between the ages of 5 and 6 years old with (n = 63) and without (n = 44) ADHD. Results: Few individual tasks achieved adequate reliability. However, confirmatory factor analysis (CFA) models identified two factors, working memory and inhibition, with test-retest correlations approaching 1.0. Multiple indicators multiple causes (MIMIC) models confirmed configural measurement invariance between the groups. Conclusion: Problems created by poor reliability, including reduced power to detect group differences, index change over time, or to identify relationships with other measures, may be mitigated using latent variable approaches.
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Affiliation(s)
| | - Karen Bierman
- The Pennsylvania State University, Department of
Psychology
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4
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Sudre G, Frederick J, Sharp W, Ishii-Takahashi A, Mangalmurti A, Choudhury S, Shaw P. Mapping associations between polygenic risks for childhood neuropsychiatric disorders, symptoms of attention deficit hyperactivity disorder, cognition, and the brain. Mol Psychiatry 2020; 25:2482-2492. [PMID: 30700802 PMCID: PMC6667324 DOI: 10.1038/s41380-019-0350-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/16/2018] [Accepted: 11/26/2018] [Indexed: 12/29/2022]
Abstract
There are now large-scale data on which common genetic variants confer risk for attention deficit hyperactivity disorder (ADHD). Here, we use mediation analyses to explore how cognitive and neural features might explain the association between common variant (polygenic) risk for ADHD and its core symptoms. In total, 544 participants participated (mean 21 years, 212 (39%) with ADHD), most with cognitive assessments, neuroanatomic imaging, and imaging of white matter tract microstructure. We found that polygenic risk for ADHD was associated with symptoms of hyperactivity-impulsivity but not inattention. This association was mediated across multiple PRS thresholds by white matter microstructure, specifically by axial diffusivity of the right corona radiata, (maximum indirect effect β = -0.034 (CI: -0.065 to -0.01), by thickness of the left dorsomedial prefrontal (β = -0.029; CI: -0.061 to -0.0047) and area of the right lateral temporal cortex (β = 0.024; CI: 0.0034-0.054). In addition, modest serial mediation was found, mapping a pathway from polygenic risk, to white matter microstructure of the anterior corona radiata, then cognition (working memory, focused attention), and finally to hyperactivity-impulsivity (working memory β = -0.014 (CI: -0.038 to -0.0026); focused attention β = -0.011 (CI: -0.033 to -0.0017). These mediation pathways were diagnostically specific and were not found for polygenic risk for ASD or schizophrenia. In conclusion, using a deeply phenotyped cohort, we delineate a pathway from polygenic risk for ADHD to hyperactive-impulsive symptoms through white matter microstructure, cortical anatomy, and cognition.
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Affiliation(s)
- Gustavo Sudre
- Neurobehavioral Clinical Research Section, Social and Behavioral Research Branch, NHGRI/NIH, Bethesda, Bethesda, MD, 20892, USA
| | - Jennifer Frederick
- Neurobehavioral Clinical Research Section, Social and Behavioral Research Branch, NHGRI/NIH, Bethesda, Bethesda, MD, 20892, USA
| | - Wendy Sharp
- Neurobehavioral Clinical Research Section, Social and Behavioral Research Branch, NHGRI/NIH, Bethesda, Bethesda, MD, 20892, USA
| | - Ayaka Ishii-Takahashi
- Neurobehavioral Clinical Research Section, Social and Behavioral Research Branch, NHGRI/NIH, Bethesda, Bethesda, MD, 20892, USA
| | - Aman Mangalmurti
- Neurobehavioral Clinical Research Section, Social and Behavioral Research Branch, NHGRI/NIH, Bethesda, Bethesda, MD, 20892, USA
| | - Saadia Choudhury
- Neurobehavioral Clinical Research Section, Social and Behavioral Research Branch, NHGRI/NIH, Bethesda, Bethesda, MD, 20892, USA
| | - Philip Shaw
- Neurobehavioral Clinical Research Section, Social and Behavioral Research Branch, NHGRI/NIH, Bethesda, Bethesda, MD, 20892, USA.
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5
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Elmaghrabi S, Nahmias MJ, Adamo N, Di Martino A, Somandepalli K, Patel V, McLaughlin A, De Sanctis V, Castellanos FX. Is Increased Response Time Variability Related to Deficient Emotional Self-Regulation in Children With ADHD? J Atten Disord 2020; 24:1045-1056. [PMID: 30047295 DOI: 10.1177/1087054718788950] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Objective: Elevated response time intrasubject variability (RT-ISV) characterizes ADHD. Deficient emotional self-regulation (DESR), defined by summating Child Behavior Checklist Anxious/Depressed, Aggressive, and Attention subscale scores, has been associated with worse outcome in ADHD. To determine if DESR is differentially associated with elevated RT-ISV, we examined RT-ISV in children with ADHD with and without DESR and in typically developing children (TDC). Method: We contrasted RT-ISV during a 6-min Eriksen Flanker Task in 31 children with ADHD without DESR, 34 with ADHD with DESR, and 65 TDC. Results: Regardless of DESR, children with ADHD showed significantly greater RT-ISV than TDC (p < .001). The ADHD subgroups, defined by presence or absence of DESR, did not differ from each other. Conclusion: Increased RT-ISV characterizes ADHD regardless of comorbid DESR. Alongside similar findings in children and adults with ADHD, these results suggest that RT-ISV is related to cognitive rather than emotional dysregulation in ADHD.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Francisco X Castellanos
- Hassenfeld Children's Hospital at NYU Langone, New York City, USA.,The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
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6
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Kim Y, Koh MK, Park KJ, Lee HJ, Yu GE, Kim HW. WISC-IV Intellectual Profiles in Korean Children and Adolescents with Attention Deficit/Hyperactivity Disorder. Psychiatry Investig 2020; 17:444-451. [PMID: 32321204 PMCID: PMC7265020 DOI: 10.30773/pi.2019.0312] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 02/28/2020] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE This study aimed to compare the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) profiles of children with attention deficit/hyperactivity disorder (ADHD) and typically-developing children (TC) in Korea. METHODS The Korean version of the WISC-IV and the Advanced Test of Attention (ATA) were administered to 377 children and adolescents: 224 with ADHD (age 8.2±2.1 years, 182 boys) and 153 TC (age 8.7±2.4 years, 68 boys). Partial correlation and an analysis of covariance were used to investigate the relationship between the scores of the WISC-IV and the ATA. RESULTS The mean score of the full-scale intelligence quotient was lower in ADHD children than in TC (p<0.001). In analyses controlling for gender and with the full-scale intelligence quotient as a covariate, the working memory index (WMI) (p<0.001) and values of the Digit span subtest (p=0.001) of the WISC-IV were lower in the ADHD group than in TC. The WMI (r=-0.26, p<0.001) and its subtest Arithmetic scores (r=-0.25, p<0.001) were negatively correlated with Commission errors on the auditory ATA. CONCLUSION Children with ADHD have significantly lower WMI scores, which were clinically correlated with Commission errors on the auditory task of the ATA. Thus, the WMI is an indicator of attention deficit in children with ADHD.
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Affiliation(s)
- Yangsik Kim
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Min Kyung Koh
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Kee Jeong Park
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Hyun-Jeong Lee
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Go Eun Yu
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Hyo-Won Kim
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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7
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Wood AC, Vainik U, Engelhardt LE, Briley DA, Grotzinger AD, Church JA, Harden KP, Tucker-Drob EM. Genetic overlap between executive functions and BMI in childhood. Am J Clin Nutr 2019; 110:814-822. [PMID: 31216571 PMCID: PMC6766443 DOI: 10.1093/ajcn/nqz109] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 05/08/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Executive functions (EFs) comprise a group of cognitive processes that selectively control and regulate attention. Inverse relations have been reported between EFs and BMI. However, the mechanisms underlying this association are not well understood. OBJECTIVES We aimed to decompose the inverse relation between EFs and BMI into genetic and environmental components. METHODS We employed a cross-sectional analysis of data from 869 twins aged 7-15 y from the Texas Twin Project, who completed a neuropsychological test battery measuring 4 EFs (switching, inhibitory control, working memory, and updating); academic achievement (reading and mathematics); and general cognitive abilities (general intelligence/intelligence quotient; crystallized and fluid intelligence; and processing speed). Participants also had their height and weight measured. RESULTS After controlling for age, sex, and race/ethnicity, BMI was inversely associated with a general EF factor representing the capacity to control and regulate goal-oriented behaviors (r = -0.125; P = 0.01; Q = 0.04). This inverse BMI-EF association was due to a significant overlap in genetic factors contributing to each phenotype (genetic correlation, rA, = -0.15; P < 0.001). Shared genetic influences accounted for 80% of the phenotypic association. CONCLUSIONS Children with higher general EF have lower BMIs, and this association is primarily attributable to shared genetic influences on both phenotypes. The results emphasize that higher weight associates not only with physical sequelae, but also with important cognitive attributes. This work adds to a growing body of research suggesting there are sets of genetic variants common across physical health and cognitive functioning.
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Affiliation(s)
- Alexis C Wood
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA,Address correspondence to ACW (e-mail: )
| | - Uku Vainik
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada,Institute of Psychology, University of Tartu, Tartu, Estonia
| | - Laura E Engelhardt
- Department of Psychology, University of Texas at Austin, Austin, TX, USA
| | - Daniel A Briley
- Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | | | - Jessica A Church
- Department of Psychology, University of Texas at Austin, Austin, TX, USA,Imaging Research Center, University of Texas at Austin, Austin, TX, USA
| | - K Paige Harden
- Department of Psychology, University of Texas at Austin, Austin, TX, USA,Population Research Center, University of Texas at Austin, Austin, TX, USA
| | - Elliot M Tucker-Drob
- Department of Psychology, University of Texas at Austin, Austin, TX, USA,Population Research Center, University of Texas at Austin, Austin, TX, USA
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8
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Du Rietz E, Coleman J, Glanville K, Choi SW, O'Reilly PF, Kuntsi J. Association of Polygenic Risk for Attention-Deficit/Hyperactivity Disorder With Co-occurring Traits and Disorders. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2018; 3:635-643. [PMID: 30047479 PMCID: PMC6278881 DOI: 10.1016/j.bpsc.2017.11.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/28/2017] [Accepted: 11/28/2017] [Indexed: 12/21/2022]
Abstract
BACKGROUND A recent large-scale mega genome-wide association study identified, for the first time, genetic variants at 12 loci significantly associated with attention-deficit/hyperactivity disorder (ADHD). In this study we use a powerful polygenic approach, with polygenic scores derived from the genome-wide association study, to investigate the etiological overlap between ADHD and frequently co-occurring traits and disorders. METHODS Polygenic risk scores for ADHD derived from the mega genome-wide association study (20,183 cases and 35,191 control subjects) were computed in a large-scale adult population sample (N = 135,726) recruited by the UK Biobank. Regression analyses were conducted to investigate whether polygenic risk for ADHD is associated with related traits and disorders in this population sample. The effects of sex were investigated via inclusion of an interaction term in the models. RESULTS Polygenic risk for ADHD significantly and positively predicted body mass index (R2 = .45%; p = 5 × 10-129), neuroticism (R2 = .09%; p = 2 × 10-24), depression (R2 = .11%; p = 2 × 10-13), anxiety (R2 = .06%; p = 3 × 10-4), risk taking (R2 = .12%; p = 9 × 10-25), alcohol intake (R2 = .09%; p = 8 × 10-29), smoking (R2 = .33%; p = 4 × 10-21), alcohol dependency (R2 = .21%; p = 5 × 10-6), and negatively predicted verbal-numerical reasoning (R2 = .38%; p = 5 × 10-36). Polygenic risk scores did not significantly predict schizophrenia or bipolar disorder, although this may be because of the small number of diagnostic cases. We found no interaction effects between polygenic risk for ADHD and sex on any phenotypes. CONCLUSIONS Our findings suggest that common genetic variation underlying risk for clinically diagnosed ADHD also contributes to higher body mass index, neuroticism, anxiety and depressive disorders, alcohol and nicotine use, risk taking, and lower general cognitive ability in the general population. These findings suggest that the co-occurrence of several traits with ADHD is partly explained by the same common genetic variants.
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Affiliation(s)
- Ebba Du Rietz
- Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny, United Kingdom
| | - Jonathan Coleman
- Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny, United Kingdom
| | - Kylie Glanville
- Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny, United Kingdom
| | - Shing Wan Choi
- Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny, United Kingdom
| | - Paul F O'Reilly
- Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny, United Kingdom
| | - Jonna Kuntsi
- Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny, United Kingdom.
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9
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Atalayer D. Dürtüsellik ve Aşırı Yeme Arasındaki İlişki: Psikolojik ve Nörobiyolojik Yaklaşımlar. PSIKIYATRIDE GUNCEL YAKLASIMLAR 2018. [DOI: 10.18863/pgy.358090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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10
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Michelini G, Kitsune V, Vainieri I, Hosang GM, Brandeis D, Asherson P, Kuntsi J. Shared and Disorder-Specific Event-Related Brain Oscillatory Markers of Attentional Dysfunction in ADHD and Bipolar Disorder. Brain Topogr 2018; 31:672-689. [PMID: 29417321 PMCID: PMC5999167 DOI: 10.1007/s10548-018-0625-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/25/2018] [Indexed: 12/28/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) often present with overlapping symptoms and cognitive impairments, such as increased fluctuations in attentional performance measured by increased reaction-time variability (RTV). We previously provided initial evidence of shared and distinct event-related potential (ERP) impairments in ADHD and BD in a direct electrophysiological comparison, but no study to date has compared neural mechanisms underlying attentional impairments with finer-grained brain oscillatory markers. Here, we aimed to compare the neural underpinnings of impaired attentional processes in ADHD and BD, by examining event-related brain oscillations during a reaction-time task under slow-unrewarded baseline and fast-incentive conditions. We measured cognitive performance, ERPs and brain-oscillatory modulations of power and phase variability in 20 women with ADHD, 20 women with BD (currently euthymic) and 20 control women. Compared to controls, both ADHD and BD groups showed increased RTV in the baseline condition and increased RTV, theta phase variability and lower contingent negative variation in the fast-incentive condition. Unlike controls, neither clinical group showed an improvement from the slow-unrewarded baseline to the fast-incentive condition in attentional P3 amplitude or alpha power suppression. Most impairments did not differ between the disorders, as only an adjustment in beta suppression between conditions (lower in the ADHD group) distinguished between the clinical groups. These findings suggest shared impairments in women with ADHD and BD in cognitive and neural variability, preparatory activity and inability to adjust attention allocation and activation. These overlapping impairments may represent shared neurobiological mechanisms of attentional dysfunction in ADHD and BD, and potentially underlie common symptoms in both disorders.
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Affiliation(s)
- Giorgia Michelini
- Institute of Psychiatry, Psychology and Neuroscience, Social, Genetic and Developmental Psychiatry Centre, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Viryanaga Kitsune
- Institute of Psychiatry, Psychology and Neuroscience, Social, Genetic and Developmental Psychiatry Centre, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Isabella Vainieri
- Institute of Psychiatry, Psychology and Neuroscience, Social, Genetic and Developmental Psychiatry Centre, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Georgina M Hosang
- Centre for Psychiatry, Wolfson Institute of Preventive Medicine, Barts & The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - Daniel Brandeis
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany.,Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric Hospital, University of Zurich, Zurich, Switzerland.,Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Philip Asherson
- Institute of Psychiatry, Psychology and Neuroscience, Social, Genetic and Developmental Psychiatry Centre, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Jonna Kuntsi
- Institute of Psychiatry, Psychology and Neuroscience, Social, Genetic and Developmental Psychiatry Centre, King's College London, De Crespigny Park, London, SE5 8AF, UK.
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11
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Faraone SV, Ghirardi L, Kuja-Halkola R, Lichtenstein P, Larsson H. The Familial Co-Aggregation of Attention-Deficit/Hyperactivity Disorder and Intellectual Disability: A Register-Based Family Study. J Am Acad Child Adolesc Psychiatry 2017; 56:167-174.e1. [PMID: 28117063 DOI: 10.1016/j.jaac.2016.11.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/07/2016] [Accepted: 12/01/2016] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Although many studies document an association between attention-deficit/hyperactivity disorder (ADHD) and intellectual disability (ID), little is known about the etiology of this comorbidity and how it should be addressed in clinical settings. We sought to clarify this issue. METHOD All individuals born in Sweden between 1987 and 2006 (n = 2,049,587) were identified using the Medical Birth Register (MBR). From this we selected 7 cohorts of relatives: 1,899,654 parent-offspring pairs, 4,180 monozygotic twin pairs, 12,655 dizygotic twin pairs, 914,848 full sibling pairs, 136,962 maternal half-sibling pairs, 134,502 paternal half-sibling pairs, and 2,790,164 full cousin pairs. We used within-individual and within-family analyses to assess the association between ADHD and ID. RESULTS Individuals with ID were at increased risk for ADHD compared to those without ID, and relatives of participants with ID were at increased risk of ADHD compared with relatives of those without ID. The magnitude of this association was positively associated with the fraction of the genome shared by the relative pair and was lower for severe compared with mild and moderate ID. Model-fitting analyses demonstrated that 91% of the correlation between the liabilities of ADHD and ID was attributable to genetic factors. CONCLUSION These data provide evidence that nearly all of the comorbidity between ADHD and ID can be attributed to genetic factors, which has implications for diagnostic practice.
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Affiliation(s)
- Stephen V Faraone
- State University of New York Upstate Medical University, Syracuse, and K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway.
| | | | | | | | - Henrik Larsson
- School of Medical Sciences, Örebro University, Örebro, Sweden
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12
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Michelini G, Kitsune GL, Cheung CHM, Brandeis D, Banaschewski T, Asherson P, McLoughlin G, Kuntsi J. Attention-Deficit/Hyperactivity Disorder Remission Is Linked to Better Neurophysiological Error Detection and Attention-Vigilance Processes. Biol Psychiatry 2016; 80:923-932. [PMID: 27591125 PMCID: PMC5120985 DOI: 10.1016/j.biopsych.2016.06.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 06/21/2016] [Accepted: 06/21/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUND The processes underlying persistence and remission of attention-deficit/hyperactivity disorder (ADHD) are poorly understood. We examined whether cognitive and neurophysiological impairments on a performance-monitoring task distinguish between ADHD persisters and remitters. METHODS On average 6 years after initial assessment, 110 adolescents and young adults with childhood ADHD (87 persisters, 23 remitters) and 169 age-matched control participants were compared on cognitive-performance measures and event-related potentials of conflict monitoring (N2) and error processing (error-related negativity and positivity) from an arrow flanker task with low-conflict and high-conflict conditions. ADHD outcome was examined with parent-reported symptoms and functional impairment measures using a categorical (DSM-IV) and a dimensional approach. RESULTS ADHD persisters were impaired compared with controls on all cognitive-performance and event-related potential measures (all p < .05). ADHD remitters differed from persisters and were indistinguishable from control participants on the number of congruent (low-conflict) errors, reaction time variability, error-related negativity, and error-related positivity (all p ≤ .05). Remitters did not differ significantly from the other groups on incongruent (high-conflict) errors, mean reaction time, and N2. In dimensional analyses on all participants with childhood ADHD, ADHD symptoms and functional impairment at follow-up were significantly correlated with congruent errors, reaction time variability, and error-related positivity (r = .19-.23, p ≤ .05). CONCLUSIONS Cognitive and neurophysiological measures of attention-vigilance and error detection distinguished ADHD remitters from persisters. These results extend our previous findings with other tasks and indicate that such measures are markers of remission and candidates for the development of nonpharmacological interventions.
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Affiliation(s)
- Giorgia Michelini
- MRC Social, Genetic and Developmental Psychiatry Centre, London, United Kingdom
| | - Glenn L Kitsune
- MRC Social, Genetic and Developmental Psychiatry Centre, London, United Kingdom; Department of Psychological Medicine, London, United Kingdom
| | - Celeste H M Cheung
- Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom; Department of Psychological Sciences, Centre for Brain and Cognitive Development, Birkbeck, University of London, London, United Kingdom
| | - Daniel Brandeis
- Department of Child and Adolescent Psychiatry and Psychotherapy , Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany; Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric Hospital, Zurich, Switzerland; Center for Integrative Human Physiology, Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Tobias Banaschewski
- Department of Child and Adolescent Psychiatry and Psychotherapy , Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Philip Asherson
- MRC Social, Genetic and Developmental Psychiatry Centre, London, United Kingdom
| | - Gráinne McLoughlin
- MRC Social, Genetic and Developmental Psychiatry Centre, London, United Kingdom
| | - Jonna Kuntsi
- MRC Social, Genetic and Developmental Psychiatry Centre, London, United Kingdom.
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Pinto R, Rijsdijk F, Ronald A, Asherson P, Kuntsi J. The Genetic Overlap of Attention-Deficit/Hyperactivity Disorder and Autistic-like Traits: an Investigation of Individual Symptom Scales and Cognitive markers. JOURNAL OF ABNORMAL CHILD PSYCHOLOGY 2016; 44:335-45. [PMID: 26021462 PMCID: PMC4729813 DOI: 10.1007/s10802-015-0037-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASDs) frequently co-occur. However, due to previous exclusionary diagnostic criteria, little is known about the underlying causes of this covariation. Twin studies assessing ADHD symptoms and autistic-like traits (ALTs) suggest substantial genetic overlap, but have largely failed to take into account the genetic heterogeneity of symptom subscales. This study aimed to clarify the phenotypic and genetic relations between ADHD and ASD by distinguishing between symptom subscales that characterise the two disorders. Moreover, we aimed to investigate whether ADHD-related cognitive impairments show a relationship with ALT symptom subscales; and whether potential shared cognitive impairments underlie the genetic risk shared between the ADHD and ALT symptoms. Multivariate structural equation modelling was conducted on a population-based sample of 1312 twins aged 7–10. Social-communication ALTs correlated moderately with both ADHD symptom domains (phenotypic correlations around 0.30) and showed substantial genetic overlap with both inattention and hyperactivity-impulsivity (genetic correlation = 0.52 and 0.44, respectively). In addition to previously reported associations with ADHD traits, reaction time variability (RTV) showed significant phenotypic (0.18) and genetic (0.32) association with social-communication ALTs. RTV captured a significant proportion (24 %) of the genetic influences shared between inattention and social-communication ALTs. Our findings suggest that social-communication ALTs underlie the previously observed phenotypic and genetic covariation between ALTs and ADHD symptoms. RTV is not specific to ADHD symptoms, but is also associated with social-communication ALTs and can, in part, contribute to an explanation of the co-occurrence of ASD and ADHD.
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Affiliation(s)
- Rebecca Pinto
- King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology, and Neuroscience, De Crespigny Park, SE5 8AF, London, UK
| | - Fruhling Rijsdijk
- King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology, and Neuroscience, De Crespigny Park, SE5 8AF, London, UK
| | - Angelica Ronald
- Department of Psychological Sciences, Birkbeck, University of London, London, UK
| | - Philip Asherson
- King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology, and Neuroscience, De Crespigny Park, SE5 8AF, London, UK
| | - Jonna Kuntsi
- King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology, and Neuroscience, De Crespigny Park, SE5 8AF, London, UK.
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An evidenced-based perspective on the validity of attention-deficit/hyperactivity disorder in the context of high intelligence. Neurosci Biobehav Rev 2016; 71:21-47. [DOI: 10.1016/j.neubiorev.2016.08.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 06/14/2016] [Accepted: 08/27/2016] [Indexed: 01/22/2023]
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15
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Tye C, Johnson KA, Kelly SP, Asherson P, Kuntsi J, Ashwood KL, Azadi B, Bolton P, McLoughlin G. Response time variability under slow and fast-incentive conditions in children with ASD, ADHD and ASD+ADHD. J Child Psychol Psychiatry 2016; 57:1414-1423. [PMID: 27465225 PMCID: PMC5132150 DOI: 10.1111/jcpp.12608] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/13/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) show significant behavioural and genetic overlap. Both ADHD and ASD are characterised by poor performance on a range of cognitive tasks. In particular, increased response time variability (RTV) is a promising indicator of risk for both ADHD and ASD. However, it is not clear whether different indices of RTV and changes to RTV according to task conditions are able to discriminate between the two disorders. METHODS Children with ASD (n = 19), ADHD (n = 18), ASD + ADHD (n = 29) and typically developing controls (TDC; n = 26) performed a four-choice RT task with slow-baseline and fast-incentive conditions. Performance was characterised by mean RT (MRT), standard deviation of RT (SD-RT), coefficient of variation (CV) and ex-Gaussian distribution measures of Mu, Sigma and Tau. RESULTS In the slow-baseline condition, categorical diagnoses and trait measures converged to indicate that children with ADHD-only and ASD + ADHD demonstrated increased MRT, SD-RT, CV and Tau compared to TDC and ASD-only. Importantly, greater improvement in MRT, SD-RT and Tau was demonstrated in ADHD and ASD + ADHD from slow-baseline to fast-incentive conditions compared to TDC and ASD-only. CONCLUSIONS Slower and more variable RTs are markers of ADHD compared to ASD and typically developing controls during slow and less rewarding conditions. Energetic factors and rewards improve task performance to a greater extent in children with ADHD compared to children with ASD. These findings suggest that RTV can be distinguished in ASD, ADHD and ASD + ADHD based on the indices of variability used and the conditions in which they are elicited. Further work identifying neural processes underlying increased RTV is warranted, in order to elucidate disorder-specific and disorder-convergent aetiological pathways.
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Affiliation(s)
- Charlotte Tye
- King's College LondonMRC Social Genetic and Developmental Psychiatry CentreInstitute of Psychiatry, Psychology & NeuroscienceLondonUK,King's College LondonChild & Adolescent PsychiatryInstitute of Psychiatry, Psychology & NeuroscienceLondonUK
| | - Katherine A. Johnson
- Melbourne School of Psychological SciencesUniversity of MelbourneMelbourneVic.Australia
| | - Simon P. Kelly
- School of Electrical and Electronic EngineeringUniversity College DublinDublinIreland
| | - Philip Asherson
- King's College LondonMRC Social Genetic and Developmental Psychiatry CentreInstitute of Psychiatry, Psychology & NeuroscienceLondonUK
| | - Jonna Kuntsi
- King's College LondonMRC Social Genetic and Developmental Psychiatry CentreInstitute of Psychiatry, Psychology & NeuroscienceLondonUK
| | - Karen L. Ashwood
- King's College LondonChild & Adolescent PsychiatryInstitute of Psychiatry, Psychology & NeuroscienceLondonUK
| | - Bahare Azadi
- King's College LondonChild & Adolescent PsychiatryInstitute of Psychiatry, Psychology & NeuroscienceLondonUK
| | - Patrick Bolton
- King's College LondonMRC Social Genetic and Developmental Psychiatry CentreInstitute of Psychiatry, Psychology & NeuroscienceLondonUK,King's College LondonChild & Adolescent PsychiatryInstitute of Psychiatry, Psychology & NeuroscienceLondonUK
| | - Gráinne McLoughlin
- King's College LondonMRC Social Genetic and Developmental Psychiatry CentreInstitute of Psychiatry, Psychology & NeuroscienceLondonUK
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16
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Pinto R, Asherson P, Ilott N, Cheung CHM, Kuntsi J. Testing for the mediating role of endophenotypes using molecular genetic data in a twin study of ADHD traits. Am J Med Genet B Neuropsychiatr Genet 2016; 171:982-92. [PMID: 27230021 PMCID: PMC5031223 DOI: 10.1002/ajmg.b.32463] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 05/12/2016] [Indexed: 11/11/2022]
Abstract
Family and twin studies have identified endophenotypes that capture familial and genetic risk in attention-deficit/hyperactivity disorder (ADHD), but it remains unclear if they lie on the causal pathway. Here, we illustrate a stepwise approach to identifying intermediate phenotypes. First, we use previous quantitative genetic findings to delineate the expected pattern of genetically correlated phenotypes. Second, we identify overlapping genetic associations with ADHD-related quantitative traits. Finally, we test for the mediating role of associated endophenotypes. We applied this approach to a sample of 1,312 twins aged 7-10. Based on previous twin model-fitting analyses, we selected hyperactivity-impulsivity, inattention, reading difficulties (RD), reaction time variability (RTV) and commission errors (CE), and tested for association with selected ADHD risk alleles. For nominally significant associations with both a symptom and a cognitive variable, matching the expected pattern based on previous genetic correlations, we performed mediation analysis to distinguish pleiotropic from mediating effects. The strongest association was observed for the rs7984966 SNP in the serotonin receptor gene (HTR2A), and RTV (P = 0.007; unadjusted for multiple testing). Mediation analysis suggested that CE (38%) and RTV (44%) substantially mediated the association between inattention and the T-allele of SNP rs3785157 in the norepinephrine transporter gene (SLC6A2) and the T-allele of SNP rs7984966 in HTR2A, respectively. The SNPs tag risk-haplotypes but are not thought to be functionally significant. While these exploratory findings are preliminary, requiring replication, this study demonstrates the value of this approach that can be adapted to the investigation of multiple genetic markers and polygenic risk scores. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Rebecca Pinto
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience; King's College London; London UK
| | - Philip Asherson
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience; King's College London; London UK
| | - Nicholas Ilott
- The Kennedy Institute of Rheumatology; University of Oxford; Oxford UK
| | - Celeste H. M. Cheung
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience; King's College London; London UK
- Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience; King's College London; London UK
| | - Jonna Kuntsi
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience; King's College London; London UK
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17
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Biscaldi M, Bednorz N, Weissbrodt K, Saville C, Feige B, Bender S, Klein C. Cognitive endophenotypes of attention deficit/hyperactivity disorder and intra-subject variability in patients with autism spectrum disorder. Biol Psychol 2016; 118:25-34. [DOI: 10.1016/j.biopsycho.2016.04.064] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 04/25/2016] [Accepted: 04/26/2016] [Indexed: 10/21/2022]
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Cheung CHM, Rijsdijk F, McLoughlin G, Brandeis D, Banaschewski T, Asherson P, Kuntsi J. Cognitive and neurophysiological markers of ADHD persistence and remission. Br J Psychiatry 2016; 208:548-55. [PMID: 26250744 PMCID: PMC4887724 DOI: 10.1192/bjp.bp.114.145185] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 12/22/2014] [Indexed: 11/23/2022]
Abstract
BACKGROUND Attention-deficit hyperactivity disorder (ADHD) persists in around two-thirds of individuals in adolescence and early adulthood. AIMS To examine the cognitive and neurophysiological processes underlying the persistence or remission of ADHD. METHOD Follow-up data were obtained from 110 young people with childhood ADHD and 169 controls on cognitive, electroencephalogram frequency, event-related potential (ERP) and actigraph movement measures after 6 years. RESULTS ADHD persisters differed from remitters on preparation-vigilance measures (contingent negative variation, delta activity, reaction time variability and omission errors), IQ and actigraph count, but not on executive control measures of inhibition or working memory (nogo-P3 amplitudes, commission errors and digit span backwards). CONCLUSIONS Preparation-vigilance measures were markers of remission, improving concurrently with ADHD symptoms, whereas executive control measures were not sensitive to ADHD persistence/remission. For IQ, the present and previous results combined suggest a role in moderating ADHD outcome. These findings fit with previously identified aetiological separation of the cognitive impairments in ADHD. The strongest candidates for the development of non-pharmacological interventions involving cognitive training and neurofeedback are the preparation-vigilance processes that were markers of ADHD remission.
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Affiliation(s)
| | | | | | | | | | | | - Jonna Kuntsi
- Celeste H. M. Cheung, MSc, King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, UK and Department of Psychology, Institute of Psychiatry, Psychology & Neuroscience, King's College London, UK; Fruhling Rijsdijk, PhD, Gráinne McLoughlin, PhD, King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, UK; Daniel Brandeis, PhD, Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany, Department of Child and Adolescent Psychiatry, University of Zurich, Zurich, Switzerland, Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland, and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland; Tobias Banaschewski, MD, PhD, Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany; Philip Asherson, MRC Psych, PhD, Jonna Kuntsi, PhD, King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, UK
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19
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Components of Motor Deficiencies in ADHD and Possible Interventions. Neuroscience 2016; 378:34-53. [PMID: 27235737 DOI: 10.1016/j.neuroscience.2016.05.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 05/10/2016] [Accepted: 05/16/2016] [Indexed: 11/23/2022]
Abstract
There is a growing body of evidence pointing at several types of motor abnormalities found in attention-deficit/hyperactivity disorder (ADHD). In this article we review findings stemming from different paradigms, and suggest an interweaving approach to the different stages involved in the motor regulation process. We start by reviewing various aspects of motor abnormalities found in ADHD and related brain mechanisms. Then, we classify reported motor impairments associated with ADHD, into four classes of motor stages: Attention to the task, motion preparation, motion execution and motion monitoring. Motor abnormalities and corresponding neural activations are analyzed in the context of each of the four identified motor patterns, along with the interactions among them and with other systems. Given the specifications and models of the role of the four motor impairments in ADHD, we ask what treatments correspond to the identified motor impairments. We analyze therapeutic interventions targeting motor difficulties most commonly experienced among individuals with ADHD; first, Neurofeedback training and EMG-biofeedback. As some of the identified components of attention, planning and monitoring have been shown to be linked to abnormal oscillation patterns in the brain, we examine neurofeedback interventions aimed to address these types of oscillations: Theta/beta frequency training and SCP neurofeedback targeted at elevating the CNV component. Additionally we discuss EMG-Biofeedback interventions targeted at feedback on motor activity. Further we review physical activity and motor interventions aimed at improving motor difficulties, associated with ADHD. These kinds of interventions are shown to be helpful not only in aspects of physical ability, but also in enhancing cognition and executive functioning.
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20
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The aetiological association between the dynamics of cortisol productivity and ADHD. J Neural Transm (Vienna) 2016; 123:991-1000. [PMID: 27106905 PMCID: PMC5005391 DOI: 10.1007/s00702-016-1534-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 02/23/2016] [Indexed: 11/25/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) has been linked to dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis, indexed by salivary cortisol. The phenotypic and aetiological association of cortisol productivity with ADHD was investigated. A selected twin design using 68 male twin-pairs aged 12–15, concordant or discordant for high ADHD symptom scores, or control twin-pairs with low ADHD symptoms, based on developmentally stable parental ADHD ratings. A genetic growth curve model was applied to cortisol samples obtained across three points during a cognitive-electroencephalography assessment, to examine the aetiological overlap of ADHD affection status (high versus low ADHD symptom scores) with latent intercept and slope factors. A significant phenotypic correlation emerged between ADHD and the slope factor, with cortisol levels dropping faster for the group with high ADHD symptom scores. The analyses further suggested this overlap was mostly driven by correlated genetic effects. We identified change in cortisol activity over time as significantly associated with ADHD affection status, primarily explained by shared genetic effects, suggesting that blunted cortisol productivity can be a marker of genetic risk in ADHD.
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Neuropsychological performance measures as intermediate phenotypes for attention-deficit/hyperactivity disorder: A multiple mediation analysis. Dev Psychopathol 2016; 29:259-272. [PMID: 27049476 DOI: 10.1017/s0954579416000195] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Genetic influences on dopaminergic neurotransmission have been implicated in attention-deficit hyperactivity disorder (ADHD) and are theorized to impact cognitive functioning via alterations in frontal-striatal circuitry. Neuropsychological functioning has been proposed to account for the potential associations between dopamine candidate genes and ADHD. However, to date, this mediation hypothesis has not been directly tested. Participants were 498 youth ages 6-17 years (mean M = 10.8 years, SD = 2.4 years, 55.0% male). All youth completed a multistage, multiple-informant assessment procedure to identify ADHD and non-ADHD cases, as well as a comprehensive neuropsychological battery. Youth provided a saliva sample for DNA analyses; the 480 base pair variable number of tandem repeat polymorphism of the dopamine active transporter 1 gene (DAT1) and the 120 base pair promoter polymorphism of the dopamine receptor D4 gene (DRD4) were genotyped. Multiple mediation analysis revealed significant indirect associations between DAT1 genotype and inattention, hyperactivity-impulsivity, and oppositionality, with specific indirect effects through response inhibition. The results highlight the role of neurocognitive task performance, particularly response inhibition, as a potential intermediate phenotype for ADHD, further elucidating the relationship between genetic polymorphisms and externalizing psychopathology.
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Moderators of neuropsychological mechanism in attention-deficit hyperactivity disorder. JOURNAL OF ABNORMAL CHILD PSYCHOLOGY 2015; 43:271-81. [PMID: 25037459 DOI: 10.1007/s10802-014-9904-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Neuropsychological measures have been proposed as both a way to tap mechanisms and as endophenotypes for child ADHD. However, substantial evidence supporting heterogeneity in neuropsychological performance among youth with ADHD as well as apparent effect differences by sex, age, and comorbidity have slowed progress. To address this, it is important to understand sibling effects in relation to these moderators. 461 youth ages 6-17 years (54.8 % male, including 251 youth with ADHD, 107 of their unaffected biological siblings, and 103 non-ADHD controls) completed diagnostic interviews and a theoretically informed battery of neuropsychological functioning. A structural equation model was used to consolidate neuropsychological domains. Group differences between unaffected siblings of youth with ADHD and controls across each domain were first examined as the primary endophenotype test for ADHD. Moderation of these effects was evaluated via investigation of interactions between diagnostic group and both proband and individual level characteristics, including sex, age, and comorbidity status. Unaffected siblings performed worse than control youth in the domains of inhibition, response time variability, and temporal information processing. Individual age moderated these effects, such that differences between controls and unaffected siblings were pronounced among younger children (ages 6-10 years) but absent among older youth (ages 11-17 years). Evidence for moderation of effects by proband sex and comorbidity status produced more variable and smaller effects. Results support the utility of inhibition, response time variability, and temporal processing as useful endophenotypes for ADHD in future genetic associations studies of the disorder, but suggest this value will vary by age among unaffected family members.
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Lin HY, Hwang-Gu SL, Gau SSF. Intra-individual reaction time variability based on ex-Gaussian distribution as a potential endophenotype for attention-deficit/hyperactivity disorder. Acta Psychiatr Scand 2015; 132:39-50. [PMID: 25612058 DOI: 10.1111/acps.12393] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/29/2014] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Intra-individual variability in reaction time (IIV-RT), defined by standard deviation of RT (RTSD), is considered as an endophenotype for attention-deficit/hyperactivity disorder (ADHD). Ex-Gaussian distributions of RT, rather than RTSD, could better characterize moment-to-moment fluctuations in neuropsychological performance. However, data of response variability based on ex-Gaussian parameters as an endophenotypic candidate for ADHD are lacking. METHOD We assessed 411 adolescents with clinically diagnosed ADHD based on the DSM-IV-TR criteria as probands, 138 unaffected siblings, and 138 healthy controls. The output parameters, mu, sigma, and tau, of an ex-Gaussian RT distribution were derived from the Conners' continuous performance test. Multi-level models controlling for sex, age, comorbidity, and use of methylphenidate were applied. RESULTS Compared with unaffected siblings and controls, ADHD probands had elevated sigma value, omissions, commissions, and mean RT. Unaffected siblings formed an intermediate group in-between probands and controls in terms of tau value and RTSD. There was no between-group difference in mu value. Conforming to a context-dependent nature, unaffected siblings still had an intermediate tau value in-between probands and controls across different interstimulus intervals. CONCLUSION Our findings suggest IIV-RT represented by tau may be a potential endophenotype for inquiry into genetic underpinnings of ADHD in the context of heterogeneity.
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Affiliation(s)
- H-Y Lin
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
| | - S-L Hwang-Gu
- Graduate Institute of Behavioral Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - S S-F Gau
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan.,Department of Psychology, Graduate Institute of Brain and Mind Sciences, Graduate Institute of Epidemiology and Preventive Medicine, Graduate Institute of Clinical Medicine, National Taiwan University, Taipei, Taiwan
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Rommel AS, Rijsdijk F, Greven CU, Asherson P, Kuntsi J. A longitudinal twin study of the direction of effects between ADHD symptoms and IQ. PLoS One 2015; 10:e0124357. [PMID: 25875897 PMCID: PMC4398424 DOI: 10.1371/journal.pone.0124357] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/01/2015] [Indexed: 11/28/2022] Open
Abstract
While the negative association between ADHD symptoms and IQ is well documented, our knowledge about the direction and aetiology of this association is limited. Here, we examine the association of ADHD symptoms with verbal and performance IQ longitudinally in a population-based sample of twins. In a population-based sample of 4,771 twin pairs, DSM-IV ADHD symptoms were obtained from the Conners' Parent Rating Scale-Revised. Verbal (vocabulary) and performance (Raven's Progressive Matrices) IQ were assessed online. ADHD symptom ratings and IQ scores were obtained at ages 12, 14 and 16 years. Making use of the genetic sensitivity and time-ordered nature of our data, we use a cross-lagged model to examine the direction of effects, while modelling the aetiologies of the association between ADHD symptoms with vocabulary and Raven's scores over time. Although time-specific aetiological influences emerged for each trait at ages 14 and 16 years, the aetiological factors involved in the association between ADHD symptoms and IQ were stable over time. ADHD symptoms and IQ scores significantly predicted each other over time. ADHD symptoms at age 12 years were a significantly stronger predictor of vocabulary and Raven's scores at age 14 years than vice versa, whereas no differential predictive effects emerged from age 14 to 16 years. The results suggest that ADHD symptoms may put adolescents at risk for decreased IQ scores. Persistent genetic influences seem to underlie the association of ADHD symptoms and IQ over time. Early intervention is likely to be key to reducing ADHD symptoms and the associated risk for lower IQ.
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Affiliation(s)
- Anna Sophie Rommel
- King’s College London, Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, London, United Kingdom
| | - Frühling Rijsdijk
- King’s College London, Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, London, United Kingdom
| | - Corina U. Greven
- King’s College London, Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, London, United Kingdom
- Radboud University Medical Centre, Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
- Karakter Child and Adolescent Psychiatry University Center, Nijmegen, The Netherlands
| | - Philip Asherson
- King’s College London, Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, London, United Kingdom
| | - Jonna Kuntsi
- King’s College London, Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, London, United Kingdom
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25
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Cheung CHM, Rijdijk F, McLoughlin G, Faraone SV, Asherson P, Kuntsi J. Childhood predictors of adolescent and young adult outcome in ADHD. J Psychiatr Res 2015; 62:92-100. [PMID: 25680235 PMCID: PMC4480336 DOI: 10.1016/j.jpsychires.2015.01.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 01/14/2015] [Accepted: 01/19/2015] [Indexed: 11/18/2022]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) often persists into adulthood, but it remains unclear which childhood factors predict future outcome. AIM To identify childhood predictors of ADHD outcome using both dimensional and categorical approaches. METHODS 116 adolescents and young adults with childhood ADHD were followed up on average 6.6 years later. ADHD outcome variables were interview-based parent-reported ADHD symptoms and impairment. Childhood predictors included parent- and teacher-rated ADHD symptoms and co-occurring behaviours; actigraph measures of activity level; socio-economic status (SES); and cognitive measures previously associated with ADHD. RESULTS Of the sample, 79% continued to meet clinical criteria of ADHD in adolescence and young adulthood. Higher parent-rated ADHD symptoms and movement intensity in childhood, but not teacher-rated symptoms, predicted ADHD symptoms at follow up. Co-occurring symptoms of oppositional behaviours, anxiety, social and emotional problems were also significant predictors, but these effects disappeared after controlling for ADHD symptoms. IQ and SES were significant predictors of both ADHD symptoms and impairment at follow up, but no other cognitive measures significantly predicted outcome. CONCLUSIONS SES and IQ emerge as potential moderators for the prognosis of ADHD. Childhood severity of ADHD symptoms, as measured by parent ratings and actigraph movement intensity, also predicts later ADHD outcome. These factors should be considered when identifying ADHD children at most risk of poor long-term outcomes and for the development of interventions to improve prognosis.
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Affiliation(s)
- Celeste H M Cheung
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Department of Psychology, Institute of Psychiatry, Psychology & Neuroscience, King's College London, UK
| | - Fruhling Rijdijk
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Gráinne McLoughlin
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Stephen V Faraone
- Departments of Psychiatry and of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, USA
| | - Philip Asherson
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Jonna Kuntsi
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
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Frazier-Wood AC, Carnell S, Pena O, Hughes SO, O’Connor TM, Asherson P, Kuntsi J. Cognitive performance and BMI in childhood: Shared genetic influences between reaction time but not response inhibition. Obesity (Silver Spring) 2014; 22:2312-8. [PMID: 25376398 PMCID: PMC4313367 DOI: 10.1002/oby.20862] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/23/2014] [Indexed: 11/10/2022]
Abstract
OBJECTIVE The aim of this work is to understand whether shared genetic influences can explain the association between obesity and cognitive performance, including slower and more variable reaction times (RTs) and worse response inhibition. METHODS RT on a four-choice RT task and the go/no-go task, and commission errors on the go/no-go task for 1,312 twins ages 7-10 years were measured. BMI was measured at 9-12 years. Biometric twin models were run to give an estimate of the genetic correlation (rG ) between body mass index (BMI) and three cognitive measures: mean RT (MRT), RT variability (RTV; the standard deviation of RTs), and commission errors (a measure of response inhibition). RESULTS Genetic correlations indicated that 20%-30% of the genes underlying BMI were shared with both RT measures. However, only small phenotypic correlations between MRT and RTV with later BMI (rPh = ∼0.1) were observed. Commission errors were unassociated with later BMI (rPh = -0.03, ns). CONCLUSIONS Our results are the first to demonstrate significant shared genetic effects between RT performance and BMI. Our findings add biological support to the notion that obesity is associated with slower and more variable RTs. However, our results also emphasize the small nature of the association, which may explain previous negative findings.
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Affiliation(s)
- Alexis C. Frazier-Wood
- USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA
| | - Susan Carnell
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | - Oscar Pena
- Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Sciences Center, Houston, Texas, USA
| | - Sheryl O. Hughes
- USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA
| | - Teresia M. O’Connor
- USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA
| | - Philip Asherson
- King’s College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, De Crespigny Park, London, UK
| | - Jonna Kuntsi
- King’s College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, De Crespigny Park, London, UK
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Cheung CHM, Fazier-Wood AC, Asherson P, Rijsdijk F, Kuntsi J. Shared cognitive impairments and aetiology in ADHD symptoms and reading difficulties. PLoS One 2014; 9:e98590. [PMID: 24886915 PMCID: PMC4041781 DOI: 10.1371/journal.pone.0098590] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 05/05/2014] [Indexed: 12/31/2022] Open
Abstract
Background Twin studies indicate that the frequent co-occurrence of attention deficit hyperactivity disorder (ADHD) symptoms and reading difficulties (RD) is largely due to shared genetic influences. Both disorders are associated with multiple cognitive impairments, but it remains unclear which cognitive impairments share the aetiological pathway, underlying the co-occurrence of the symptoms. We address this question using a sample of twins aged 7–10 and a range of cognitive measures previously associated with ADHD symptoms or RD. Methods We performed multivariate structural equation modelling analyses on parent and teacher ratings on the ADHD symptom domains of inattention and hyperactivity, parent ratings on RD, and cognitive data on response inhibition (commission errors, CE), reaction time variability (RTV), verbal short-term memory (STM), working memory (WM) and choice impulsivity, from a population sample of 1312 twins aged 7–10 years. Results Three cognitive processes showed significant phenotypic and genetic associations with both inattention symptoms and RD: RTV, verbal WM and STM. While STM captured only 11% of the shared genetic risk between inattention and RD, the estimates increased somewhat for WM (21%) and RTV (28%); yet most of the genetic sharing between inattention and RD remained unaccounted for in each case. Conclusion While response inhibition and choice impulsivity did not emerge as important cognitive processes underlying the co-occurrence between ADHD symptoms and RD, RTV and verbal memory processes separately showed significant phenotypic and genetic associations with both inattention symptoms and RD. Future studies employing longitudinal designs will be required to investigate the developmental pathways and direction of causality further.
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Affiliation(s)
- Celeste H. M. Cheung
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, United Kingdom
| | - Alexis C. Fazier-Wood
- Human Genetics Center, Division of Epidemiology, Human Genetics and Environmental Science, School of Public Health, University of Texas Health Sciences Center at Houston, Houston, Texas, United States of America
| | - Philip Asherson
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, United Kingdom
| | - Fruhling Rijsdijk
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, United Kingdom
| | - Jonna Kuntsi
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, United Kingdom
- * E-mail:
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Kuntsi J. Commentary: From noise to insight? Reaction time variability in ADHD and autism spectrum disorders--a commentary on Karalunas et al. (2014). J Child Psychol Psychiatry 2014; 55:711-3. [PMID: 24840175 DOI: 10.1111/jcpp.12262] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/28/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Jonna Kuntsi
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, UK
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Karalunas SL, Geurts HM, Konrad K, Bender S, Nigg JT. Annual research review: Reaction time variability in ADHD and autism spectrum disorders: measurement and mechanisms of a proposed trans-diagnostic phenotype. J Child Psychol Psychiatry 2014; 55:685-710. [PMID: 24628425 PMCID: PMC4267725 DOI: 10.1111/jcpp.12217] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/24/2014] [Indexed: 12/11/2022]
Abstract
BACKGROUND Intraindividual variability in reaction time (RT) has received extensive discussion as an indicator of cognitive performance, a putative intermediate phenotype of many clinical disorders, and a possible trans-diagnostic phenotype that may elucidate shared risk factors for mechanisms of psychiatric illnesses. SCOPE AND METHODOLOGY Using the examples of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorders (ASD), we discuss RT variability. We first present a new meta-analysis of RT variability in ASD with and without comorbid ADHD. We then discuss potential mechanisms that may account for RT variability and statistical models that disentangle the cognitive processes affecting RTs. We then report a second meta-analysis comparing ADHD and non-ADHD children on diffusion model parameters. We consider how findings inform the search for neural correlates of RT variability. FINDINGS Results suggest that RT variability is increased in ASD only when children with comorbid ADHD are included in the sample. Furthermore, RT variability in ADHD is explained by moderate to large increases (d = 0.63-0.99) in the ex-Gaussian parameter τ and the diffusion parameter drift rate, as well as by smaller differences (d = 0.32) in the diffusion parameter of nondecision time. The former may suggest problems in state regulation or arousal and difficulty detecting signal from noise, whereas the latter may reflect contributions from deficits in motor organization or output. The neuroimaging literature converges with this multicomponent interpretation and also highlights the role of top-down control circuits. CONCLUSION We underscore the importance of considering the interactions between top-down control, state regulation (e.g., arousal), and motor preparation when interpreting RT variability and conclude that decomposition of the RT signal provides superior interpretive power and suggests mechanisms convergent with those implicated using other cognitive paradigms. We conclude with specific recommendations for the field for next steps in the study of RT variability in neurodevelopmental disorders.
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Affiliation(s)
- Sarah L Karalunas
- Department of Psychiatry, Oregon Health and Science University, Portland, OR, USA
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Kuntsi J, Pinto R, Price TS, van der Meere JJ, Frazier-Wood AC, Asherson P. The separation of ADHD inattention and hyperactivity-impulsivity symptoms: pathways from genetic effects to cognitive impairments and symptoms. JOURNAL OF ABNORMAL CHILD PSYCHOLOGY 2014; 42:127-36. [PMID: 23839718 PMCID: PMC4520068 DOI: 10.1007/s10802-013-9771-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Both shared and unique genetic risk factors underlie the two symptom domains of attention deficit hyperactivity disorder (ADHD): inattention and hyperactivity-impulsivity. The developmental course and relationship to co-occurring disorders differs across the two symptom domains, highlighting the importance of their partially distinct etiologies. Familial cognitive impairment factors have been identified in ADHD, but whether they show specificity in relation to the two ADHD symptom domains remains poorly understood. We aimed to investigate whether different cognitive impairments are genetically linked to the ADHD symptom domains of inattention versus hyperactivity-impulsivity. We conducted multivariate genetic model fitting analyses on ADHD symptom scores and cognitive data, from go/no-go and fast tasks, collected on a population twin sample of 1,312 children aged 7-10. Reaction time variability (RTV) showed substantial genetic overlap with inattention, as observed in an additive genetic correlation of 0.64, compared to an additive genetic correlation of 0.31 with hyperactivity-impulsivity. Commission errors (CE) showed low additive genetic correlations with both hyperactivity-impulsivity and inattention (genetic correlations of 0.17 and 0.11, respectively). The additive genetic correlation between RTV and CE was also low and non-significant at -0.10, consistent with the etiological separation between the two indices of cognitive impairments. Overall, two key cognitive impairments phenotypically associated with ADHD symptoms, captured by RTV and CE, showed different genetic relationships to the two ADHD symptom domains. The findings extend a previous model of two familial cognitive impairment factors in combined subtype ADHD by separating pathways underlying inattention and hyperactivity-impulsivity symptoms.
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Affiliation(s)
- Jonna Kuntsi
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, De Crespigny Park, London, SE5 8AF, UK,
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Feige B, Biscaldi M, Saville CWN, Kluckert C, Bender S, Ebner-Priemer U, Hennighausen K, Rauh R, Fleischhaker C, Klein C. On the temporal characteristics of performance variability in attention deficit hyperactivity disorder (ADHD). PLoS One 2013; 8:e69674. [PMID: 24204553 PMCID: PMC3805479 DOI: 10.1371/journal.pone.0069674] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 06/15/2013] [Indexed: 01/09/2023] Open
Abstract
Increased intra-subject variability of reaction times (ISV-RT) is one of the most consistent findings in attention-deficit/hyperactivity disorder (ADHD). Although the nature of this phenomenon is still unclear, it has been hypothesised to reflect interference from the Default Mode Network (DMN). So far, ISV-RT has been operationally defined either as a frequency spectrum of the underlying RT time series, or as a measure of dispersion of the RT scores distribution. Here, we use a novel RT analysis framework to link these hitherto unconnected facets of ISV-RT by determining the sensitivity of different measures of RT dispersion to the frequency content of the underlying RT time series. N=27 patients with ADHD and N=26 healthy controls performed several visual N-back tasks. Different measures of RT dispersion were repeatedly modelled after individual frequency bands of the underlying RT time series had been either extracted or suppressed using frequency-domain filtering. We found that the intra-subject standard deviation of RT preserves the "1/f noise" characteristic typical of human RT data. Furthermore and most importantly, we found that the ex-Gaussian parameter τ is rather exclusively sensitive to frequencies below 0.025 Hz in the underlying RT time series and that the particularly slow RTs, which nourish τ, occur regularly as part of an quasi-periodic, ultra-slow RT fluctuation. Overall, our results are compatible with the idea that ISV-RT is modulated by an endogenous, slowly fluctuating process that may reflect DMN interference.
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Affiliation(s)
- Bernd Feige
- Department Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany
| | - Monica Biscaldi
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany
| | - Christopher W. N. Saville
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany
- School of Psychology, Bangor University, Bangor, United Kingdom
| | - Christian Kluckert
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany
| | - Stephan Bender
- Department of Child and Adolescent Psychiatry, University of Dresden, Dresden, Germany
| | - Ulrich Ebner-Priemer
- Department of Applied Psychology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Klaus Hennighausen
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany
| | - Reinhold Rauh
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany
| | - Christian Fleischhaker
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany
| | - Christoph Klein
- Department of Child and Adolescent Psychiatry and Psychotherapy, University of Freiburg, Freiburg, Germany
- School of Psychology, Bangor University, Bangor, United Kingdom
- *E-mail:
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Kuntsi J, Frazier-Wood AC, Banaschewski T, Gill M, Miranda A, Oades RD, Roeyers H, Rothenberger A, Steinhausen HC, van der Meere JJ, Faraone SV, Asherson P, Rijsdijk F. Genetic analysis of reaction time variability: room for improvement? Psychol Med 2013; 43:1323-1333. [PMID: 22975296 PMCID: PMC3801159 DOI: 10.1017/s0033291712002061] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/26/2012] [Accepted: 07/27/2012] [Indexed: 11/18/2022]
Abstract
BACKGROUND Increased reaction time variability (RTV) on cognitive tasks requiring a speeded response is characteristic of several psychiatric disorders. In attention deficit hyperactivity disorder (ADHD), the association with RTV is strong phenotypically and genetically, yet high RTV is not a stable impairment but shows ADHD-sensitive improvement under certain conditions, such as those with rewards. The state regulation theory proposed that the RTV difference score, which captures change from baseline to a rewarded or fast condition, specifically measures 'state regulation'. By contrast, the interpretation of RTV baseline (slow, unrewarded) scores is debated. We aimed to investigate directly the degree of phenotypic and etiological overlap between RTV baseline and RTV difference scores. Method We conducted genetic model fitting analyses on go/no-go and fast task RTV data, across task conditions manipulating rewards and event rate, from a population-based twin sample (n=1314) and an ADHD and control sibling-pair sample (n=1265). RESULTS Phenotypic and genetic/familial correlations were consistently high (0.72-0.98) between RTV baseline and difference scores, across tasks, manipulations and samples. By contrast, correlations were low between RTV in the manipulated condition and difference scores. A comparison across two different go/no-go task RTV difference scores (slow-fast/slow-incentive) showed high phenotypic and genetic/familial overlap (r = 0.75-0.83). CONCLUSIONS Our finding that RTV difference scores measure largely the same etiological process as RTV under baseline condition supports theories emphasizing the malleability of the observed high RTV. Given the statistical shortcomings of difference scores, we recommend the use of RTV baseline scores for most analyses, including genetic analyses.
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Affiliation(s)
- J Kuntsi
- King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, UK.
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Karalunas SL, Huang-Pollock CL, Nigg JT. Decomposing attention-deficit/hyperactivity disorder (ADHD)-related effects in response speed and variability. Neuropsychology 2013; 26:684-94. [PMID: 23106115 DOI: 10.1037/a0029936] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE Slow and variable reaction times (RTs) on fast tasks are such a prominent feature of attention-deficit/hyperactivity disorder (ADHD) that any theory must account for them. However, this has proven difficult because the cognitive mechanisms responsible for this effect remain unexplained. Although speed and variability are typically correlated, it is unclear whether single or multiple mechanisms are responsible for group differences in each. RTs are a result of several semi-independent processes, including stimulus encoding, rate of information processing, speed-accuracy trade-offs, and motor response, which have not been previously well characterized. METHOD A diffusion model was applied to RTs from a forced-choice RT paradigm in two large, independent case-control samples (NCohort 1 = 214 and NCohort 2 = 172). The decomposition measured three validated parameters that account for the full RT distribution and assessed reproducibility of ADHD effects. RESULTS In both samples, group differences in traditional RT variables were explained by slow information processing speed, and unrelated to speed-accuracy trade-offs or nondecisional processes (e.g., encoding, motor response). CONCLUSIONS RT speed and variability in ADHD may be explained by a single information processing parameter, potentially simplifying explanations that assume different mechanisms are required to account for group differences in the mean and variability of RTs.
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Affiliation(s)
- Sarah L Karalunas
- ADHD Research Study UHN80R1, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-9979, USA.
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Biederman J, Fried R, Petty C, Mahoney L, Faraone SV. An examination of the impact of attention-deficit hyperactivity disorder on IQ: a large controlled family-based analysis. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2012; 57:608-16. [PMID: 23072952 DOI: 10.1177/070674371205701005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Although children with attention-deficit hyperactivity disorder (ADHD) have, on average, lower intelligence quotient (IQ) scores than control subjects, the reasons for these deficits remain unknown. Because IQ is highly familial, we investigated whether children with ADHD have a decrement in IQ from expectations based on parental IQ. METHOD Subjects were 276 children with ADHD and 239 control subjects of similar age and sex. Expected IQ was calculated based on biological parents' estimated IQ. A significant discrepancy between observed and expected estimated IQ was defined by a child scoring 15 IQ points or more lower than expected, based on parental IQ. RESULTS Compared with control subjects, children with ADHD were significantly more likely to have lower than expected estimated IQ scores based on parental IQ, though this finding was accounted for by a small subgroup of children with ADHD who had an IQ 15 points or more lower than expected, based on parental IQ. These children were more likely to be female, have higher psychopathological, neuropsychological, educational, and interpersonal deficits, as well as higher rates of perinatal complications. CONCLUSIONS Group differences in IQ scores between children with and without ADHD reported in the literature may be accounted for by a subgroup of children with ADHD who have a large decrement in IQ from expectations based on parental IQ. Although perinatal complications may explain these findings, more work is needed to better understand the etiology of these IQ deficits.
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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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Differential brain development with low and high IQ in attention-deficit/hyperactivity disorder. PLoS One 2012; 7:e35770. [PMID: 22536435 PMCID: PMC3335015 DOI: 10.1371/journal.pone.0035770] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 03/26/2012] [Indexed: 01/20/2023] Open
Abstract
Attention-Deficit/Hyperactivity Disorder (ADHD) and intelligence (IQ) are both heritable phenotypes. Overlapping genetic effects have been suggested to influence both, with neuroimaging work suggesting similar overlap in terms of morphometric properties of the brain. Together, this evidence suggests that the brain changes characteristic of ADHD may vary as a function of IQ. This study investigated this hypothesis in a sample of 108 children with ADHD and 106 typically developing controls, who participated in a cross-sectional anatomical MRI study. A subgroup of 64 children also participated in a diffusion tensor imaging scan. Brain volumes, local cortical thickness and average cerebral white matter microstructure were analyzed in relation to diagnostic group and IQ. Dimensional analyses investigated possible group differences in the relationship between anatomical measures and IQ. Second, the groups were split into above and below median IQ subgroups to investigate possible differences in the trajectories of cortical development. Dimensionally, cerebral gray matter volume and cerebral white matter microstructure were positively associated with IQ for controls, but not for ADHD. In the analyses of the below and above median IQ subgroups, we found no differences from controls in cerebral gray matter volume in ADHD with below-median IQ, but a delay of cortical development in a number of regions, including prefrontal areas. Conversely, in ADHD with above-median IQ, there were significant reductions from controls in cerebral gray matter volume, but no local differences in the trajectories of cortical development. In conclusion, the basic relationship between IQ and neuroanatomy appears to be altered in ADHD. Our results suggest that there may be multiple brain phenotypes associated with ADHD, where ADHD combined with above median IQ is characterized by small, more global reductions in brain volume that are stable over development, whereas ADHD with below median IQ is associated more with a delay of cortical development.
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Frazier-Wood AC, Bralten J, Arias-Vasquez A, Luman M, Ooterlaan J, Sergeant J, Faraone SV, Buitelaar J, Franke B, Kuntsi J, Rommelse NNJ. Neuropsychological intra-individual variability explains unique genetic variance of ADHD and shows suggestive linkage to chromosomes 12, 13, and 17. Am J Med Genet B Neuropsychiatr Genet 2012; 159B:131-40. [PMID: 22223442 DOI: 10.1002/ajmg.b.32018] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 12/08/2011] [Indexed: 01/23/2023]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable neuropsychiatric disorder that is usually accompanied by neuropsychological impairments. The use of heritable, psychometrically robust traits that show association with the disorder of interest can increase the power of gene-finding studies. Due to the robust association of intra-individual variability with ADHD on a phenotypic and genetic level, intra-individual variability is a prime candidate for such an attempt. We aimed to combine intra-individual variability measures across tasks into one more heritable measure, to examine the relatedness to other cognitive factors, and to explore the genetic underpinnings through quantitative trait linkage analysis. Intra-individual variability measures from seven tasks were available for 238 ADHD families (350 ADHD-affected and 195 non-affected children) and 147 control families (271 children). Intra-individual variability measures from seven different tasks shared common variance and could be used to construct an aggregated measure. This aggregated measure was largely independent from other cognitive factors related to ADHD and showed suggestive linkage to chromosomes 12q24.3 (LOD = 2.93), 13q22.2 (LOD = 2.36), and 17p13.3 (LOD = 2.00). A common intra-individual variability construct can be extracted from very diverse neuropsychological tasks; this construct taps into unique genetic aspects of ADHD and may relate to loci conferring risk for ADHD (12q24.3 and 17p13.3) and possibly autism (12q24.3). Given that joining of data across sites boosts the power for genetic analyses, our findings are promising in showing that intra-individual variability measures are viable candidates for across site analyses where different tasks have been used.
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Affiliation(s)
- Alexis C Frazier-Wood
- Department of Epidemiology and Section on Statistical Genetics, University of Alabama at Birmingham, School of Public Health, USA
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Rommelse NN, Geurts HM, Franke B, Buitelaar JK, Hartman CA. A review on cognitive and brain endophenotypes that may be common in autism spectrum disorder and attention-deficit/hyperactivity disorder and facilitate the search for pleiotropic genes. Neurosci Biobehav Rev 2011; 35:1363-96. [DOI: 10.1016/j.neubiorev.2011.02.015] [Citation(s) in RCA: 249] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 02/25/2011] [Accepted: 02/27/2011] [Indexed: 02/01/2023]
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Wood AC, Rijsdijk F, Johnson KA, Andreou P, Albrecht B, Arias-Vasquez A, Buitelaar JK, McLoughlin G, Rommelse NNJ, Sergeant JA, Sonuga-Barke EJS, Uebel H, van der Meere JJ, Banaschewski T, Gill M, Manor I, Miranda A, Mulas F, Oades RD, Roeyers H, Rothenberger A, Steinhausen HC, Faraone SV, Asherson P, Kuntsi J. The relationship between ADHD and key cognitive phenotypes is not mediated by shared familial effects with IQ. Psychol Med 2011; 41:861-871. [PMID: 20522277 PMCID: PMC3430513 DOI: 10.1017/s003329171000108x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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.
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Affiliation(s)
- A C Wood
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, UK.
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Electrophysiological markers of genetic risk for attention deficit hyperactivity disorder. Expert Rev Mol Med 2011; 13:e9. [PMID: 21426626 DOI: 10.1017/s1462399411001797] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder with complex genetic aetiology. The identification of candidate intermediate phenotypes may facilitate the detection of susceptibility genes and neurobiological mechanisms underlying the disorder. Electroencephalography (EEG) is an ideal neuroscientific approach, providing a direct measurement of neural activity that demonstrates reliability, developmental stability and high heritability. This systematic review evaluates the utility of a subset of electrophysiological measures as potential intermediate phenotypes for ADHD: quantitative EEG indices of arousal and intraindividual variability, and functional investigations of attention, inhibition and performance monitoring using the event-related potential (ERP) technique. Each measure demonstrates consistent and meaningful associations with ADHD, a degree of genetic overlap with ADHD and potential links to specific genetic variants. Investigations of the genetic and environmental contributions to EEG/ERP and shared genetic overlap with ADHD might enhance molecular genetic studies and provide novel insights into aetiology. Such research will aid in the precise characterisation of the clinical deficits seen in ADHD and guide the development of novel intervention and prevention strategies for those at risk.
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Paloyelis Y, Rijsdijk F, Wood AC, Asherson P, Kuntsi J. The genetic association between ADHD symptoms and reading difficulties: the role of inattentiveness and IQ. JOURNAL OF ABNORMAL CHILD PSYCHOLOGY 2011; 38:1083-95. [PMID: 20556504 PMCID: PMC2964469 DOI: 10.1007/s10802-010-9429-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous studies have documented the primarily genetic aetiology for the stronger phenotypic covariance between reading disability and ADHD inattention symptoms, compared to hyperactivity-impulsivity symptoms. In this study, we examined to what extent this covariation could be attributed to “generalist genes” shared with general cognitive ability or to “specialist” genes which may specifically underlie processes linking inattention symptoms and reading difficulties. We used multivariate structural equation modeling on IQ, parent and teacher ADHD ratings and parent ratings on reading difficulties from a general population sample of 1312 twins aged 7.9–10.9 years. The covariance between reading difficulties and ADHD inattention symptoms was largely driven by genetic (45%) and child-specific environment (21%) factors not shared with IQ and hyperactivity-impulsivity; only 11% of the covariance was due to genetic effects common with IQ. Aetiological influences shared among all phenotypes explained 47% of the variance in reading difficulties. The current study, using a general population sample, extends previous findings by showing, first, that the shared genetic variability between reading difficulties and ADHD inattention symptoms is largely independent from genes contributing to general cognitive ability and, second, that child-specific environment factors, independent from IQ, also contribute to the covariation between reading difficulties and inattention symptoms.
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Affiliation(s)
- Yannis Paloyelis
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, UK.
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Kuntsi J, Klein C. Intraindividual variability in ADHD and its implications for research of causal links. Curr Top Behav Neurosci 2011; 9:67-91. [PMID: 21769722 DOI: 10.1007/7854_2011_145] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Intraindividual variability (IIV) - reflecting short-term (within-session), within-person fluctuations in behavioral performance - and, specifically, reaction time (RT) variability, is strongly linked with attention-deficit hyperactivity disorder (ADHD) both at the phenotypic and genetic levels. Phenotypic case-control comparisons show a consistent and robust association between ADHD and RT variability across a broad range of cognitive tasks, samples, and age ranges (from childhood to adulthood). The association does not appear to be a nonspecific effect mediated by lower general cognitive ability. The finding from quantitative genetic studies of the shared genetic etiology between ADHD and RT variability is similarly robust, replicating across tasks, samples, and definitions of ADHD. Molecular genetic studies have produced intriguing initial findings: increasing sample sizes and replications across datasets remain priorities for future efforts. While the field has come a long way from considering increased RT variability in ADHD as the "noise" or "error" that we need to reduce in our data, the investigation of the causal pathways is only beginning. The neural basis of IIV is being investigated, with initial data pointing to a crucial role of fronto-striatal systems in controlling behavioral consistency. Several theories have been put forward to account for the observed IIV in ADHD, including accounts of arousal regulation, temporal processing and the "default-mode network." For the wider implications of the IIV phenomenon to be fully realized, we need to learn further about the underlying processes, their developmental context, and about shared and unique causal pathways across disorders where high RT variability is observed.
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Affiliation(s)
- Jonna Kuntsi
- King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, De Crespigny Park, London, SE5 8AF, UK,
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Corvin A, Donohoe G, Hargreaves A, Gallagher L, Gill M. The cognitive genetics of neuropsychiatric disorders. Curr Top Behav Neurosci 2011; 12:579-613. [PMID: 22367920 DOI: 10.1007/7854_2011_188] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Classification in psychiatry is heavily dependent on clinical symptoms and illness course. This ignores the critical role that cognitive problems play in neuropsychiatric disorders affecting different domains across the lifespan, from ADHD and autism to schizophrenia and Alzheimers disease. At this point, it is unclear whether cognitive mechanisms are specific to disorders, whether multiple processes can contribute to the same disorder, or whether aberrant neural processing can result in many different phenotypic outcomes. Understanding this would allow us to better grasp normal as well as pathological brain function. This could inform diagnostics based on understanding of neurophysiological processes and the consequent development of new therapeutics. Genetics, and the development of genomic research, offers real opportunities to understand the molecular mechanisms relevant to cognition. This chapter defines and describes the main cognitive phenotypes, which are investigated in psychiatric disorders. We review evidence for their heritability and early progress in the field using cytogenetic, linkage and candidate gene-based research methodologies. With high-throughput genomics it is now possible to explore novel common and rare risk variants for psychiatric disorders and their role in cognitive function at a genome-wide level. We review the results of early genomic studies and discuss the novel insights that they are starting to provide. Finally, we review the analysis of whole-genome DNA sequence data and the challenges that this will bring for cognitive genomics research.
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Affiliation(s)
- A Corvin
- Department of Psychiatry, Trinity College Dublin, Dublin, Ireland,
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Attention Deficit Hyperactivity Disorder (ADHD) among longer-term prison inmates is a prevalent, persistent and disabling disorder. BMC Psychiatry 2010; 10:112. [PMID: 21176203 PMCID: PMC3016316 DOI: 10.1186/1471-244x-10-112] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 12/22/2010] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND ADHD is a common and disabling disorder, with an increased risk for coexisting disorders, substance abuse and delinquency. In the present study, we aimed at exploring ADHD and criminality. We estimated the prevalence of ADHD among longer-term prison inmates, described symptoms and cognitive functioning, and compared findings with ADHD among psychiatric outpatients and healthy controls. METHODS At Norrtälje Prison, we approached 315 male inmates for screening of childhood ADHD by the Wender Utah Rating Scale (WURS-25) and for present ADHD by the Adult ADHD Self-Report Screener (ASRS-Screener). The response rate was 62%. Further, we assessed 34 inmates for ADHD and coexisting disorders. Finally, we compared findings with 20 adult males with ADHD, assessed at a psychiatric outpatient clinic and 18 healthy controls. RESULTS The estimated prevalence of adult ADHD among longer-term inmates was 40%. Only 2 out of 30 prison inmates confirmed with ADHD had received a diagnosis of ADHD during childhood, despite most needed health services and educational support. All subjects reported lifetime substance use disorder (SUD) where amphetamine was the most common drug. Mood and anxiety disorders were present among half of subjects; autism spectrum disorder (ASD) among one fourth and psychopathy among one tenth. Personality disorders were common; almost all inmates presented conduct disorder (CD) before antisocial personality disorder (APD). Prison inmates reported more ADHD symptoms during both childhood and adulthood, compared with ADHD psychiatric outpatients. Further, analysis of executive functions after controlling for IQ showed both ADHD groups performed poorer than controls on working memory tests. Besides, on a continuous performance test, the ADHD prison group displayed poorer results compared with both other groups. CONCLUSIONS This study suggested ADHD to be present among 40% of adult male longer-term prison inmates. Further, ADHD and coexisting disorders, such as SUD, ASD, personality disorders, mood- and anxiety disorders, severely affected prison inmates with ADHD. Besides, inmates showed poorer executive functions also when controlling for estimated IQ compared with ADHD among psychiatric outpatients and controls. Our findings imply the need for considering these severities when designing treatment programmes for prison inmates with ADHD.
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Kuntsi J, Wood AC, Rijsdijk F, Johnson KA, Andreou P, Albrecht B, Arias-Vasquez A, Buitelaar JK, McLoughlin G, Rommelse NNJ, Sergeant JA, Sonuga-Barke EJ, Uebel H, van der Meere JJ, Banaschewski T, Gill M, Manor I, Miranda A, Mulas F, Oades RD, Roeyers H, Rothenberger A, Steinhausen HC, Faraone SV, Asherson P. Separation of cognitive impairments in attention-deficit/hyperactivity disorder into 2 familial factors. ACTA ACUST UNITED AC 2010; 67:1159-67. [PMID: 21041617 DOI: 10.1001/archgenpsychiatry.2010.139] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
CONTEXT Attention-deficit/hyperactivity disorder (ADHD) is associated with widespread cognitive impairments, but it is not known whether the apparent multiple impairments share etiological roots or separate etiological pathways exist. A better understanding of the etiological pathways is important for the development of targeted interventions and for identification of suitable intermediate phenotypes for molecular genetic investigations. OBJECTIVES To determine, by using a multivariate familial factor analysis approach, whether 1 or more familial factors underlie the slow and variable reaction times, impaired response inhibition, and choice impulsivity associated with ADHD. DESIGN An ADHD and control sibling-pair design. SETTING Belgium, Germany, Ireland, Israel, Spain, Switzerland, and the United Kingdom. PARTICIPANTS A total of 1265 participants, aged 6 to 18 years: 464 probands with ADHD and 456 of their siblings (524 with combined-subtype ADHD), and 345 control participants. MAIN OUTCOME MEASURES Performance on a 4-choice reaction time task, a go/no-go inhibition task, and a choice-delay task. RESULTS The final model consisted of 2 familial factors. The larger factor, reflecting 85% of the familial variance of ADHD, captured 98% to 100% of the familial influences on mean reaction time and reaction time variability. The second, smaller factor, reflecting 13% of the familial variance of ADHD, captured 62% to 82% of the familial influences on commission and omission errors on the go/no-go task. Choice impulsivity was excluded in the final model because of poor fit. CONCLUSIONS The findings suggest the existence of 2 familial pathways to cognitive impairments in ADHD and indicate promising cognitive targets for future molecular genetic investigations. The familial distinction between the 2 cognitive impairments is consistent with recent theoretical models--a developmental model and an arousal-attention model--of 2 separable underlying processes in ADHD. Future research that tests the familial model within a developmental framework may inform developmentally sensitive interventions.
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Affiliation(s)
- Jonna Kuntsi
- MRC Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom.
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Szekely A, Balota DA, Duchek JM, Nemoda Z, Vereczkei A, Sasvari-Szekely M. Genetic factors of reaction time performance: DRD4 7-repeat allele associated with slower responses. GENES BRAIN AND BEHAVIOR 2010; 10:129-36. [DOI: 10.1111/j.1601-183x.2010.00645.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wood AC, Neale MC. Twin studies and their implications for molecular genetic studies: endophenotypes integrate quantitative and molecular genetics in ADHD research. J Am Acad Child Adolesc Psychiatry 2010; 49:874-83. [PMID: 20732624 PMCID: PMC3148177 DOI: 10.1016/j.jaac.2010.06.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 06/07/2010] [Accepted: 06/10/2010] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To describe the utility of twin studies for attention-deficit/hyperactivity disorder (ADHD) research and demonstrate their potential for the identification of alternative phenotypes suitable for genomewide association, developmental risk assessment, treatment response, and intervention targets. METHOD Brief descriptions of the classic twin study and genetic association study methods are provided, with illustrative findings from ADHD research. Biometrical genetics refers to the statistical modeling of data gathered from one or more group of known biological relation; it was apparently coined by Francis Galton in the 1860s and led to the "Biometrical School" at the University of London. Twin studies use genetic correlations between pairs of relatives, derived using this theoretical framework, to parse the individual differences in a trait into latent (unmeasured) genetic and environmental influences. This method enables the estimation of heritability, i.e., the percentage of variance due to genetic influences. It is usually implemented with a method called structural equation modeling, which is a statistical technique for fitting models to data, typically using maximum likelihood estimation. Genetic association studies aim to identify those genetic variants that account for the heritability estimated in twin studies. Measurements other than those used for the clinical diagnosis of the disorder are popular phenotype choices in current ADHD research. It is argued that twin studies have great potential to refine phenotypes relevant to ADHD. RESULTS Prior studies have consistently found that the majority of the variance in ADHD symptoms is due to genetic factors. To date, genomewide association studies of ADHD have not identified replicable associations that account for the heritable variation. Possibly, the application of genomewide association studies to these alternative phenotypic measurements will assist in identifying the pathways from genetic variants to ADHD. CONCLUSION Power to detect associations should be improved by the study of highly heritable endophenotypes for ADHD and by reducing the number of phenotypes to be considered. Therefore, twin studies are an important research tool in the development of endophenotypes, defined as alternative, more highly heritable traits that act at earlier stages of the pathway from genes to behavior. Although genetic variation in liability to ADHD is likely polygenic, the proposed approach should help to identify improved alternative measurements for genetic association studies.
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