Altered intrinsic organisation of brain networks implicated in attentional processes in adult attention-deficit/hyperactivity disorder: a resting state study of attention, default mode and salience network connectivity

Deficits in task-related attentional engagement in attention-deficit/hyperactivity disorder (ADHD) have been hypothesized to be due to altered interrelationships between attention, default mode and salience networks. We examined the intrinsic connectivity during rest within and between these networks. Six minutes resting state scans were obtained. Using a network-based approach, connectivity within and between the dorsal and ventral attention, the default mode and the salience networks was compared between the ADHD and control group. The ADHD group displayed hyperconnectivity between the two attention networks and within the default mode and ventral attention network. The salience network was hypoconnected to the dorsal attention network. There were trends towards hyperconnectivity within the dorsal attention network and between the salience and ventral attention network in ADHD. Connectivity within and between other networks was unrelated to ADHD. Our findings highlight the altered connectivity within and between attention networks, and between them and the salience network in ADHD. One hypothesis to be tested in future studies is that individuals with ADHD are affected by an imbalance between ventral and dorsal attention systems with the former playing a dominant role during task engagement making individuals with ADHD highly susceptible to distraction by salient task-irrelevant stimuli

A Growth Mixture Modeling Study of Learning Trajectories in an Extended Computerized Working Memory Training Programme Developed for Young Children Diagnosed With Attention-Deficit/Hyperactivity Disorder

This study explored (1) whether growth mixture modeling (GMM) could identify different trajectories of learning efficiency during a working memory (WM) training programme for young children diagnosed with Attention Deficit Hyperactivity Disorder (ADHD), compared with a typically developing (TD) control group, and (2) if learning trajectories and outcomes were different for simple and complex training tasks. Children completed simple visuospatial short-term memory (VSSTM) and complex visuospatial WM (VSWM) tasks for 15 min a day, 5 days a week, and for 8 weeks. Parent-reported executive functioning, and children's WM and attention control, educational achievement, and IQ were measured prior to (T1), immediately following (T2) and 3 months after training (T3). GMM analysis showed that WM training was represented as one learning curve, and there was no difference for the trajectories of the ADHD and TD groups. The learning trajectory for the VSSTM tasks across groups was represented as one learning curve and for the VSWM tasks there were three learning curves. Learning for the VSSTM tasks and for most children in the VSWM tasks was characterized by an inverted-U shape, indicating that training was effective for up to 15 sessions, was stable and declined thereafter, highlighting an optimal training timeframe. For the VSWM tasks, the two remaining groups showed either a U-shaped or a high inverted U-shaped trajectory, with the latter group achieving the highest T1T2 change score (i.e., children showed a lower starting point and the most gain in terms of learning and post-training performance). There were no broader benefits of training at post-test or follow-up. Further research should explore who would benefit most from intensive cognitive training, as well as the potential benefits for mental health and well-being

The familial basis of facial emotion recognition deficits in adolescents with conduct disorder and their unaffected relatives

Background. There is accumulating evidence of impairments in facial emotion recognition in adolescents with conduct disorder (CD). However, the majority of studies in this area have only been able to demonstrate an association, rather than a causal link, between emotion recognition deficits and CD. To move closer towards understanding the causal pathways linking emotion recognition problems with CD, we studied emotion recognition in the unaffected first-degree relatives of CD probands, as well as those with a diagnosis of CD. Method. Using a family-based design, we investigated facial emotion recognition in probands with CD (n = 43), their unaffected relatives (n = 21), and healthy controls (n = 38). We used the Emotion Hexagon task, an alternative forced-choice task using morphed facial expressions depicting the six primary emotions, to assess facial emotion recognition accuracy. Results. Relative to controls, the CD group showed impaired recognition of anger, fear, happiness, sadness and surprise (all p < 0.005). Similar to probands with CD, unaffected relatives showed deficits in anger and happiness recognition relative to controls (all p < 0.008), with a trend toward a deficit in fear recognition. There were no significant differences in performance between the CD probands and the unaffected relatives following correction for multiple comparisons. Conclusions. These results suggest that facial emotion recognition deficits are present in adolescents who are at increased familial risk for developing antisocial behaviour, as well as those who have already developed CD. Consequently, impaired emotion recognition appears to be a viable familial risk marker or candidate endophenotype for CD

Inhibitory Deficits, Delay Aversion and Preschool AD/HD: Implications for the Dual Pathway Model

The dual pathway model proposes the existence of separate and neurobiologically distinct cognitive (inhibitory and more general executive dysfunction) and motivational (delay aversion) developmental routes to AD/HD. The study reported in this paper explores the relation between inhibitory deficits and delay aversion and their association with AD/HD in a group of three-year-old children. Children identified as having a pre-school equivalent of AD/HD (N=19) and controls (N=19), matched for gender and IQ, completed a battery of inhibition and delay tasks. Correlational and factor analysis supported a dissociation between inhibitory deficits (go-no-go, set shifting) and delay aversion (choice delay) with delay of gratification cross-loading. Children with AD/HD displayed more inhibitory deficits and were more delay averse than controls. The data support the value of the distinction between motivational and cognitive pathways to AD/HD. Furthermore, the data suggest that such a distinction is apparent relatively early on during development

Genotype moderates the impact of food additives on hyperactive behavior in children

Introduction: The claim of a relationship between artificial food color and additive (AFCs) intake and behavior is highly contentious. We have shown in a previous population-based trial with 3yo children adverse effects of food additives on parentally-rated hyperactive behaviour (Bateman et al, 2004). The possible role of genetic polymorphisms in moderating this adverse effect has not been previously examined. Methods A randomised, double blind, placebo-controlled, within subject crossover food challenge was used for 144, 8 to 9 year old children and 153, 3 year old children. Following baseline assessment children were placed on a diet eliminating food additives and a benzoate preservative for 6 weeks during which time they were challenged for weekly periods with either a placebo mix or a drink containing sodium benzoate (45mg daily) and one of two mixes of AFCs.: Results: The T939C and Thr105Ile polymorphisms of the histamine N-methyltransferase gene (HNMT) moderated the adverse effect s of AFCs but the polymorphisms in catecholamine genes COMT Val108Met and ADRA2A C1291G did not. These findings point to a possible role for histamine in mediating the effects of food additives and help to explain why there has been inconsistency between previous studies. Conclusions: Genes influencing a range of neurotransmitter systems and their interplay with environmental factors, such as diet, need to be examined to understand genetic influences on hyperactivity.<br/

The impact of digital experiences on adolescents with mental health vulnerabilities: a multimethod pilot study

In public, professional and academic debates, a link is often made between a rise in rates of mental health problems experienced by adolescents and their increasing use of the internet. This report describes the first pilot stage of a research project collaboration between King’s College London (KCL) and the London School of Economics and Political Science (LSE) exploring the Dynamic Interplay of Online Risk and Resilience in Adolescence (DIORA). DIORA focuses on internet use and its relationship to mental health in adolescents made vulnerable by pre-existing mental health problems

The impact of childhood deprivation on adult neuropsychological functioning is associated with ADHD symptom persistence

Background: Institutional deprivation in early childhood is associated with neuropsychological deficits in adolescence. Using 20-year follow-up data from a unique natural experiment – the large scale adoption of children exposed to extreme deprivation in Romanian institutions in the 1980s – we examined, for the first time, whether such deficits are still present in adulthood and whether they are associated with deprivation-related symptoms of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).Methods: Adult neuropsychological functioning was assessed across five domains (inhibitory control, facial emotion recognition, decision-making, prospective memory and IQ) in 70 previously-institutionalized adoptees (mean age= 25.3, 50% female) and 22 non-deprived UK adoptees (comparison group, mean age= 24.6, 41% female). ADHD and ASD symptoms were assessed using parent-completed questionnaires.Results: Early institutionalization was associated with impaired performance on all tasks in adulthood. Prospective memory deficits persisted after controlling for IQ. ADHD and ASD symptoms were positively correlated. After controlling for ASD symptoms, ADHD symptoms remained associated with deficits in IQ, prospective memory, proactive inhibition, decision-making quality and emotionrecognition. ASD symptoms were not independently associated with neuropsychological deficits when accounting for their overlap with ADHD symptoms. Multiple regression analysis revealed that the link between childhood deprivation and adult ADHD symptoms was statistically explained by deprivation-related differences in adult IQ and prospective memory.Conclusions: These results represent some of the most compelling evidence to date of the enduring power of early, time-limited childhood adversity to impair neuropsychological functioning across the lifespan – effects that are linked specifically to deprivation-related adult ADHD symptoms