There is debate regarding the dimensional versus categorical nature of attention-deficit/hyperactivity disorder (ADHD). This study utilized confirmatory factor analysis to examine this issue. ADHD symptoms rated on interviews and rating scales from a large sample of individuals (ages 3-17, 74 % male, 75 % Caucasian) with ADHD were examined (n = 242). Four potential factor structures were tested to replicate prior findings in a sample with a wide age range and included only participants who met DSM-IV-TR diagnostic criteria for ADHD. Correlations with executive function measures were performed to further assess the separability and validity of the derived factors. The data support a bifactor model with a general ADHD factor and two specific factors, inattention and hyperactivity/impulsivity. Importantly, the individual factors were also differentially correlated with executive functioning measures. This study adds to a growing literature suggesting both a general component to ADHD, as well as dimensional traits of inattention and hyperactivity/impulsivity, associated with distinct executive functioning profiles. The presence of a general underlying factor contraindicates separating the inattentive and combined subtypes of ADHD into distinct disorders.
"However, previous factor analytic research of SCT has not addressed whether SCT is independent from ADHD as a diagnostic category because studies have not taken into account the bi-factor structure of ADHD. Despite growing evidence that symptoms of ADHD are best represented by a bi-factor model (Gomez et al., 2013; Martel et al., 2010; Normand, Flora, Toplak, & Tannock, 2012; Smith et al., 2013; Toplak et al., 2012), SCT factor analytic studies have modeled SCT as a third factor in a single-order two-factor model of ADHD. Such models do not explicitly model inattention and hyperactivity/impulsivity symptoms loading "
[Show abstract][Hide abstract] ABSTRACT: Objective:
Studies demonstrate sluggish cognitive tempo (SCT) symptoms to be distinct from inattentive and hyperactive-impulsive dimensions of ADHD. No study has examined SCT within a bi-factor model of ADHD, whereby SCT may form a specific factor distinct from inattention and hyperactivity/impulsivity while still fitting within a general ADHD factor, which was the purpose of the current study.
A total of 168 children were recruited from an ADHD clinic. Most (92%) met diagnostic criteria for ADHD. Parents and teachers completed measures of ADHD and SCT.
Although SCT symptoms were strongly associated with inattention, they loaded onto a factor independent of ADHD g. Results were consistent across parent and teacher ratings.
SCT is structurally distinct from inattention as well as from the general ADHD latent symptom structure. Findings support a growing body of research suggesting SCT to be distinct and separate from ADHD.
Journal of Attention Disorders 07/2014; DOI:10.1177/1087054714539995 · 3.78 Impact Factor
"ß 2014 Elsevier B.V. All rights reserved. (South et al., 2007; Smith et al., 2013), and this is supported by the fact that deficits in EF are very often seen in patients with neurodevelopmental disorders, including ASD and ADHD. Several studies have proposed that the symptoms of ADHD mainly arise from a primary deficit in a specific EF domain such as response inhibition (Corbett et al., 2009) or working memory (Willcutt et al., 2005), while the symptoms of ASD arise from a primary deficit in planning and flexibility (Sinzig et al., 2008). "
[Show abstract][Hide abstract] ABSTRACT: Children with attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) share many common symptoms, including attention deficit, behavioral problems, and difficulties with social skills. The aim of this study is to distinguish between ASD and ADHD by identifying the characteristic features of both the disorders, by using multidimensional assessments, including screening behavioral checklists, cognitive assessments, and comprehensive neurological battery. After screening for comorbid disorders, we carefully selected age-, sex-, IQ-, and socio-economic status-matched children with typical development (TD). In the Wechsler Intelligence Scale for children, a lower score was observed for the ASD group than for the TD group in Picture Concept, which is a subscale of Perceptual Reasoning. A lower score was shown by the ADHD group than by the TD group in the spatial working memory test in the Cambridge Neuropsychological Test Automated Battery (CANTAB®). Although ASD and ADHD have many similar symptoms, they can be differentiated by focusing on the behavioral and cognitive characteristics of executive function.
Asian Journal of Psychiatry 07/2014; 12(1). DOI:10.1016/j.ajp.2014.06.011
"Although ADHD is often diagnosed as a unitary construct , factor analytic studies consistently confirm a two-dimensional structure of inattention and hyperactivity/impulsivity [8,9], each associated with distinct correlates and executive dysfunction. Hyperactivity symptoms tend to decline more with age, in contrast to inattention, and are associated with conduct problems , disinhibition and behavioral dysregulation , and substance misuse . Hyperactivity also appears more likely to be associated with violence. "
[Show abstract][Hide abstract] ABSTRACT: It is unclear whether the association between Attention Deficit/Hyperactivity Disorder (ADHD) and violence is explained by ADHD symptoms or co-existing psychopathology. We investigated associations of ADHD and its symptom domains of hyperactivity and inattention, among individuals reporting violence in the UK population.
We report data from the Adult Psychiatric Morbidity Survey (2007), a representative sample of the household population of England. A randomly selected sample of 7,369 completed the Adult Self-Report Scale for ADHD and the self-reported violence module, including repetition, injury, minor violence, victims and location of incidents. All models were weighted to account for non-response and carefully adjusted for demography and clinical predictors of violence: antisocial personality, substance misuse and anxiety disorders.
ADHD was moderately associated with violence after adjustments (OR 1.75, p = .01). Hyperactivity, but not inattention was associated with several indicators of violence in the domestic context (OR 1.16, p = .03). Mild and moderate ADHD symptoms were significantly associated with violence repetition, but not severe ADHD where the association was explained by co-existing disorders. Stratified analyses further indicated that most violence reports are associated with co-occurring psychopathology.
The direct effect of ADHD on violence is only moderate at the population level, driven by hyperactivity, and involving intimate partners and close persons. Because violence associated with severe ADHD is explained by co-existing psychopathology, interventions should primarily target co-existing disorders.
PLoS ONE 09/2013; 8(9):e75575. DOI:10.1371/journal.pone.0075575 · 3.23 Impact Factor
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