Plugging the attention deficit: perceptual load counters increased distraction in ADHD

Objective: Increased vulnerability to extraneous distraction is a key symptom of Attention-Deficit Hyperactivity Disorder (ADHD), which may have particularly disruptive consequences. Here we apply Load Theory of attention to increase understanding of this symptom, and to explore a potential method for ameliorating it. Previous research in nonclinical populations has highlighted increased perceptual load as a means of improving the ability to focus attention and avoid distraction. The present study examines whether adults with ADHD can also benefit from conditions of high perceptual load to improve their focused attention abilities. Method: We tested adults with ADHD and age- and IQ-matched controls on a novel measure of irrelevant distraction under load, designed to parallel the form of distraction that is symptomatic of ADHD. During a letter search task, in which perceptual load was varied through search set size, participants were required to ignore salient yet entirely irrelevant distractors (colorful images of cartoon characters) presented infrequently (10% of trials). Results: The presence of these distractors produced a significantly greater interference effect on the search RTs for the adults with ADHD compared with controls, p = .005, ηp² = .231. Perceptual load, however, significantly reduced distractor interference for the ADHD group and was as effective in reducing the elevated distractor interference in ADHD as it was for controls. Conclusions: These findings clarify the nature of the attention deficit underlying increased distraction in ADHD, and demonstrate a tangible method for overcoming it. (PsycINFO Database Record (c) 2013 APA, all rights reserved)

Transient expression analysis of allelic variants of a VNTR in the dopamine transporter gene (DAT1)

BACKGROUND: The 10-repeat allele of a variable number tandem repeat (VNTR) polymorphism in the 3'-untranslated region of the dopamine transporter gene (DAT1) has been associated with a range of psychiatric phenotypes, most notably attention-deficit hyperactivity disorder. The mechanism for this association is not yet understood, although several lines of evidence implicate variation in gene expression. In this study we have characterised the genomic structure of the 9- and 10-repeat VNTR alleles, and directly examined the role of the polymorphism in mediating gene expression by measuring comparative in vitro cellular expression using a reporter-gene assay system. RESULTS: Differences in the sequence of the 9- and 10- repeat alleles were confirmed but no polymorphic differences were observed between individuals. There was no difference in expression of reporter gene constructs containing the two alleles. CONCLUSIONS: Our data suggests that this VNTR polymorphism may not have a direct effect on DAT1 expression and that the associations observed with psychiatric phenotypes may be mediated via linkage disequilibrium with other functional polymorphisms

How ‘lofty’ art can help the medical world reimagine mental health

Towards cultural change: re-imagining mental health through ‘lofty’ art We are amidst a global mental health crisis. To bring about policy and culture change, we must think outside the pillbox. Through an ACE-funded Unlimited commission #MagicCarpet, we argue for 'lofty arts’ in effecting cultural change in mental health

Hyperactive-Impulsive Symptom Scores and Oppositional Behaviours Reflect Alternate Manifestations of a Single Liability

Attention deficit hyperactivity disorder (ADHD) and oppositional behaviours frequently co-occur, We aimed to study the etiology of this overlap in a general population–based twin sample, assessing the symptom domains of hyperactivity-impulsivity and inattentiveness separately for their overlap with oppositionality. We further aimed to investigate whether rater bias may contribute to the overlap in previous data which used one rater only. Using parent and teacher ratings on hyperactivity-impulsivity, inattentiveness and oppositionality, and actigraph measurements of activity level, for 668 7-9-year-old twin pairs, oppositionality showed a higher overlap with hyperactivity-impulsivity (r=.95) than with inattentiveness (r=.52) and all etiological influences on hyperactivity-impulsivity were shared with those on oppositionality, indicated by a genetic correlation of .95 and a child-specific environmental correlation of .94. Actigraph data did not show an overlap with ratings of oppositionality. In middle childhood, symptoms of hyperactivity-impulsivity and oppositional behaviour may represent the same underlying liability, whereas the inattentive domain is more distinct

A systematic review of attention deficit hyperactivity disorder (ADHD) and mathematical ability: current findings and future implications

Background: Several recent behavioural and behavioural genetic studies have investigated the relationship between attention deficit hyperactivity disorder (ADHD) and mathematical ability. The aim of this systematic review was to provide an overview of these studies to date. An emphasis was placed on reviewing results that explored the association between mathematics and the two ADHD components of attention and hyperactivity-impulsivity separately. Methods: A systematic search of quantitative studies investigating the association between mathematics and ADHD was conducted across five databases (PsychINFO, Web of Science, PubMed, EMBASE, and Scopus). A total of 30 cross-sectional and four longitudinal studies were included in this review. Results: Narrative synthesis of the results was provided using PRISMA guidelines. Taken together, the studies pointed at substantial evidence for a negative association between ADHD symptoms and mathematical ability. This association was particularly marked for the inattentive component of ADHD than for the hyperactive-impulsive component. Evidence from twin studies also showed a significant genetic correlation between mathematics and ADHD, which was greater for the inattentive component of ADHD compared to the hyperactive-impulsive component. Conclusions: The differential relationship of the hyperactivity-impulsivity and inattention domains with mathematics emphasises the heterogeneity within the disorder and suggests a partially different aetiology of the two ADHD domains. A better understanding of the aetiology of ADHD could help develop more efficient interventions aimed at the reduction of its symptoms. It could also offer an explanatory framework for shortcomings in achievement an

Efficacy of atomoxetine in adults with attention deficit hyperactivity disorder:An integrated analysis of the complete database of multicenter placebo-controlled trials

Persistence of attention deficit hyperactivity disorder (ADHD) into adulthood can be disabling or lead to substantial impairment. Several clinical trials of atomoxetine (ATX) in adults with ADHD have been reported following the National Institute for Health and Clinical Excellence (NICE) guidelines issued in 2008. We performed an integrated analysis of all Eli Lilly-sponsored, randomized, double-blind, placebo-controlled studies of ATX in adults with ADHD completed as of May 2012. Individual patient data were pooled from six short-term (10–16 week) studies (1961 patients) and three longer-term (six-month) studies (1413 patients). In the short-term analysis, ATX patients achieved a significantly greater mean reduction in ADHD symptoms than placebo patients (−12.2 vs −8.1; Conners’ Adult ADHD Rating Scale–Investigator-Rated: Screening Version (CAARS-Inv: SV); p<0.001). In the longer-term analysis, respective improvements after six months were −13.2 vs −9.7 (p<0.001). Response rates at study endpoints for ATX vs placebo, based on CAARS-Inv: SV improvement ≥30% and Clinical Global Impressions of ADHD-Severity (CGI-ADHD-S) ≤3 were 34.8% vs 22.3% in the short-term and 43.4% vs 28.0% after six months, and CAARS-Inv: SV improvements ≥40% were 41.3% vs 25.3% in the short-term and 44.0% vs 31.4% after six months (all p<0.001). Overall, ATX had a clinically significant effect in adults with ADHD, with reductions in core symptoms and clinically meaningful responder rates

The IMAGE project: methodological issues for the molecular genetic analysis of ADHD

The genetic mechanisms involved in attention deficit hyperactivity disorder (ADHD) are being studied with considerable success by several centres worldwide. These studies confirm prior hypotheses about the role of genetic variation within genes involved in the regulation of dopamine, norepinephrine and serotonin neurotransmission in susceptibility to ADHD. Despite the importance of these findings, uncertainties remain due to the very small effects sizes that are observed. We discuss possible reasons for why the true strength of the associations may have been underestimated in research to date, considering the effects of linkage disequilibrium, allelic heterogeneity, population differences and gene by environment interactions. With the identification of genes associated with ADHD, the goal of ADHD genetics is now shifting from gene discovery towards gene functionality – the study of intermediate phenotypes ('endophenotypes'). We discuss methodological issues relating to quantitative genetic data from twin and family studies on candidate endophenotypes and how such data can inform attempts to link molecular genetic data to cognitive, affective and motivational processes in ADHD. The International Multi-centre ADHD Gene (IMAGE) project exemplifies current collaborative research efforts on the genetics of ADHD. This European multi-site project is well placed to take advantage of the resources that are emerging following the sequencing of the human genome and the development of international resources for whole genome association analysis. As a result of IMAGE and other molecular genetic investigations of ADHD, we envisage a rapid increase in the number of identified genetic variants and the promise of identifying novel gene systems that we are not currently investigating, opening further doors in the study of gene functionality

Cognitive-electrophysiological indices of attentional and inhibitory processing in adults with ADHD: familial effects

Background Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that starts in childhood and frequently persists in adults. In a comparison of adults with ADHD and a matched control sample, we previously showed that abnormal inhibitory processing is typically preceded or accompanied by other processing deficits in adult ADHD. We now compare these data further to additional data from first-degree relatives (fathers) of children with ADHD to identify whether this pattern of abnormal processing shares familial influences with ADHD in adults. Methods Using a family design, we compared 20 fathers of children with the combined subtype of ADHD with 21 adults with ADHD combined subtype and 20 controls in event-related potential indices of preparatory states and subsequent response inhibition processing as elicited by a cued continuous performance task. Results Fathers of children with ADHD exhibited significantly weaker orienting attention to cues and inhibitory processing than the controls but not the ADHD sample. Conclusions These findings provide evidence for the familial association of attentional orienting and response inhibition processes with ADHD in adults and indicate a familial and neurobiological link between ADHD in children and adults