Comorbid Externalising Behaviour in AD/HD: Evidence for a Distinct Pathological Entity in Adolescence

Abstract

While the profiling of subtypes of Attention Deficit Hyperactivity Disorder (AD/HD) have been the subject of considerable scrutiny, both psychometrically and psychophysiologically, little attention has been paid to the effect of diagnoses comorbid with AD/HD on such profiles. This is despite the greater than 80% prevalence of comorbidity under the DSM-IV-TR diagnostic definitions. Here we investigate the event related potential (ERP) and psychometric profiles of Controls, AD/HD, and comorbid AD/HD (particularly AD/HD+ODD/CD) groups on six neurocognitive tasks thought to probe the constructs of selective and sustained attention, response inhibition and executive function. Data from 29 parameters extracted from a child group (age range 6 to 12; 52 Controls and 64 AD/HD) and from an adolescent group (age range 13 to 17; 79 Controls and 88 AD/HD) were reduced via a Principal Components Analysis, the 6 significant eigenvectors then used as determinants of cluster membership via a Two-Step Cluster Analysis. Two clusters were found in the analysis of the adolescent age group - a cluster dominated by Control and AD/HD participants without comorbidity, while the second cluster was dominated by AD/HD participants with externalising comorbidity (largely oppositional defiant/conduct disorder ODD/CD). A similar segregation within the child age group was not found. Further analysis of these objectively determined clusters in terms of their clinical diagnoses indicates a significant effect of ODD/CD comorbidity on a concurrent AD/HD diagnosis. We conclude that comorbid externalising behaviour in AD/HD constitutes a distinct pathological entity in adolescence.

Auditory and Visual Attention Performance in Children With ADHD: The Attentional Deficiency of ADHD Is Modality Specific

“…Children diagnosed with ADHD vary widely in the types and severity of symptoms that they demonstrate, but the disorder is generally characterized by low levels of attention and concentration, and high levels of activity, distractibility, impulsivity, and the inability to inhibit inappropriate actions (American Psychiatric Association, 2000). Numerous studies using objective, laboratory-based measures of neuropsychological functioning in individuals with ADHD have found deficits in sustained attention, inhibitory control, and target detection (Berwid et al, 2005; Pasini, Paloscia, Alessandrelli, Porfirio, & Curatolo, 2007; Perera et al, 2012; Stern & Shalev, 2013; Tucha et al, 2009; Wang et al, 2011). However, these studies focused primarily on the visual modality, despite the importance of the auditory modality and auditory attention to many areas of learning and functioning.…”

Massive Withdrawal Symptoms and Affective Vulnerability Are Associated with Variants of the CHRNA4 Gene in a Subgroup of Smokers

“…Reconsidering the possible background of these conflicting data on CHRNA4, we tried to find an alternative method for detecting significant effect of CHRNA4 on smoking-related phenotypes. Phenotypic cluster analysis is a recently proposed method for identifying more homogenous subgroups based on parallel analysis of co-existing phenotypic variables [11] . Furthermore, it has been proved to be a promising method for genetic association studies of complex diseases such as asthma and substance use disorders [12] .…”