Stimulation seeking and hyperactive behavior in children with ADHD: a re-analysis

To examine the stimulation-seeking function of hyperactivity in children with ADHD, Antrop and colleagues analyzed the behavior of 30 hyperactive and 30 nonhyperactive children during a waiting situation, either with or without extra stimulation. The behavior was assessed by frequency measures. In their study it was hypothesized that children with ADHD would show a greater decrease in activity in the presence of stimulation than control children. Since confirmation for this hypothesis was only found for 2 of 25 target behaviors, the present re-analysis included other behavioral measures to assess two relationships: first, how hyperactivity varies under fixed time conditions, using measures of duration and intensity of behavior instead of frequency measures, and second, how the perceived duration of waiting time affects behavior. Analysis indicated that children with ADHD showed a greater decrease in behavior in the presence of stimulation for touching objects and movements of trunk, as reported. Further, children who underestimated the waiting period were more apt to seek additional stimulation in its absence than those who overestimated the waiting period.     

Waiting impulsivity: a distinctive feature of ADHD neuropsychology?

Impulsivity is a core feature of attention-deficit hyperactivity disorder (ADHD). It has been conceptualized in a number of different ways. In the current article, we examine how the new concept of “waiting impulsivity”, which refers to premature responding before a scheduled target appears, adds to our understanding of impulsivity in ADHD. Sixty children (8–12 years old; 30 ADHD; 30 typically developing controls) completed the 4-choice serial reaction time task, a measure of waiting impulsivity, alongside tasks measuring inhibitory control and temporal discounting and questionnaires measuring behavioral disorder symptoms, delay aversion, and various aspects of impulsivity. A multiple logistic regression model was used to explore the contribution of the primary task outcomes to predict group membership. Children with ADHD displayed more waiting impulsivity and less inhibitory control; they did not differ in temporal discounting. There was no correlation between waiting impulsivity and inhibitory control. Waiting impulsivity was correlated with parent-reported ratings of hyperactivity/impulsivity, inattention, oppositional defiant disorder (ODD), and conduct disorder (CD) and with self-reported delay aversion ratings. Only waiting impulsivity was a significant predictor of ADHD status. In conclusion, waiting impulsivity is distinct from inhibitory control deficits and predicts ADHD status independently of it. Future research needs to examine the relationship with delay aversion and ODD/CD more thoroughly.     

Family Interactions in Children With and Without ADHD

We used global ratings to compare the family (parent[s]-child) interactions of 51 clinic-referred children with ADHD and 32 non problem children. Children and parent(s) were videotaped while engaging in problem solving and game playing activities. Independent coders, blind to children's diagnostic status, rated the interactions using measures designed to assess interaction competence and quality. Significant group differences emerged between the ADHD and control groups during problem solving on the interaction quality measures of Warmth, Engagement and Communication. Comparisons of the interactions of families of children with ADHD, with (ADHD W) and without (ADHD W/O) comorbid disruptive behavior disorders, were non significant, although increased symptomology was associated with reduced Warmth and Engagement during problem solving. Irrespective of group membership family interactions were more positive during game playing versus problem solving.     

The effects of co‐occurring ADHD symptoms on electrophysiological correlates of cognitive control in young people with Tourette syndrome

Efficient cognitive control is implicated in tic control in young people with Tourette syndrome (TS). Attention‐deficit/hyperactivity disorder (ADHD) frequently co‐occurs with TS and is associated with impaired cognitive control. Young people with TS and ADHD (TS+ADHD) show poorer cognitive control performance than those with TS, but how co‐occurring ADHD affects underlying neural activity is unknown. We investigated this issue by examining behavioural and event‐related potential (ERP) correlates of cognitive control in young people with these conditions. Participants aged 9–17 with TS (n = 17), TS+ADHD (n = 17), ADHD (n = 11), and unaffected controls (n = 20) performed a visual Go/Nogo task during electroencephalography (EEG) recording. Behavioural performance measures (D‐prime, RT, reaction time variability, post‐error slowing) and ERP measures (N2, P3, error‐related negativity (ERN), error positivity (Pe)) were analysed in a 2 (TS‐yes, TS‐no) × 2 (ADHD‐yes, ADHD‐no) factorial analysis to investigate the effects of TS, ADHD, and their interaction. The results of these analyses showed that ADHD was associated with poorer performance and reduced amplitude of all ERPs, reflecting widespread cognitive control impairments. Tourette syndrome was associated with slowed RTs, which might reflect a compensatory slowing of motor output to facilitate tic control. There was no interaction between the TS and ADHD factors for any behavioural or ERP measure, indicating the impairing effects of ADHD on behaviour and electrophysiological markers of cognitive control were present in TS+ADHD and that RT slowing associated with TS was unaffected by co‐occurring ADHD symptoms.     

Developmental change in the relation between executive functions and symptoms of ADHD and co‐occurring behaviour problems

In a sample of 92 children aged 6–13 years this study investigates the normal developmental change in the relation between executive functioning (EF) and the core behavioural symptoms associated with attention deficit hyperactivity disorder (ADHD) (hyperactivity/impulsivity and inattention) as well as symptoms often co‐occurring with childhood hyperactivity (conduct‐ and internalizing problems). EF was assessed by using multiple tests grouped through prior factor analysis, resulting in cognitive measures relating to disinhibition, speed/arousal, verbal working memory, non‐verbal working memory, and fluency. The results showed that although disinhibition was positively related to hyperactivity/impulsivity and inattention mainly for the youngest age group, there were no significant age effects for these relations. Instead, age effects were found for the relations between speed/arousal and inattention as well as for the relations between verbal working memory/fluency and inattention. In the oldest age group poor performance on these cognitive measures was associated with high ratings of inattention. For the total sample a relation was obtained between disinhibition and hyperactivity/impulsivity as well as between both working memory measures and internalizing problems. In conclusion, the results from this study suggest that poor inhibition is most clearly associated with ADHD symptoms for younger children, whereas poor functioning with regard to later developing and more complex executive functions such as working memory and fluency is associated with ADHD symptoms for older children. Copyright © 2006 John Wiley & Sons, Ltd.     

Observation of children with attention‐deficit hyperactivity (ADHD) problems in three natural classroom contexts

Background. Observation studies of students with attention‐deficit hyperactivity disorder (ADHD) problems in natural classroom situations are costly and relatively rare. Aims. The study enquired how teacher ratings are anchored in actual student classroom behaviours, and how the behaviour of children with ADHD problems differs from their classmates. The authors attempted to broaden the usual focus on disruptive and inattentive behaviours to elucidate the role of various on‐task behaviours, as well as considering differences between classroom contexts. Sample. DSM‐III‐R criteria were used in conjunction with a teacher rating scale to select a sample of 55 students with ADHD problems, and 55 matched controls from a population of 569 primary school students. Method. Students were observed in their natural classrooms using the Munich Observation of Attention Inventory (MAI; Helmke, 1988 ). Correlations between teacher reports and observation codes were computed, and systematic differences between students with ADHD problems and controls in different classroom contexts were examined using a generalized linear mixed model (GLMM). Results. Global teacher reports showed moderate to strong correlations with observed student behaviours. Expected on‐task behaviour demonstrated the strongest relationship (r >?.70) with teacher reports. As hypothesized, the children with ADHD were more disruptive and inattentive than their matched peers. They were also less often inconspicuous on‐task as expected by their teachers. However, their behaviour was assigned to two other on‐task categories more often than their peers, and this raised their total on‐task behaviour to over 66%. Situational differences were found for all codes as well, which mostly affected all students in a similar way, not just students with ADHD. Conclusions. ADHD related behaviours are pervasive across the classroom situations coded. Teachers appear to distinguish between desirable and undesirable on‐task behaviours. Nevertheless, assisting students with ADHD problems requires shaping both. Future studies need to include more differentiated codes for various types of on‐task behaviours and also need to code the lesson context concurrently.     

Differentiating Type A behaviour and hyperactivity using observed motivation during a reaction time task

In light of the previously found overlap between Type A behaviour as measured by the Matthews Youth Test for Health (MYTH) and hyperactivity scales, the overall aim of this study was to clarify the standing of MYTH‐defined Type A behaviour relative to hyperactivity and Attention‐Deficit/Hyperactivity Disorder (ADHD), using observed task motivation and performance on a choice reaction‐time task, the Complex Reaction Time (CRT) measure. This study included 21 boys exhibiting Type A behaviour, 22 ADHD boys, 20 non‐clinically hyperactive boys, and 20 non‐hyperactive boys, between the ages of 6 and 13 years. It was proposed that a differentiation of constructs would be possible using observed task motivation if the MYTH were a discriminantly valid measure of Type A behaviour. Results showed that the MYTH‐defined Type A group differed from the clinically diagnosed ADHD group, although it was markedly similar to the non‐clinical hyperactive group, displaying comparable CRT performance and low level of task motivation. Type A behaviour correlated to CRT performance and task motivation in a way which was conceptually more indicative of hyperactivity than of Type A behaviour, which questions the validity of the MYTH as a measure of the Type A construct. The MYTH Impatience subscale was found to be particularly impure with regard to hyperactivity. Copyright © 2003 John Wiley & Sons, Ltd.     

Moral/non‐moral domain shift in young adolescents in relation to delinquent behaviour

Because moral transgressions are considered more serious than non‐moral (i.e. conventional or personal) transgressions, it is less threatening to self‐esteem to interpret one's own delinquent act as a non‐moral transgression rather than a moral transgression. This ‘domain shift’ could be a way of reducing cognitive dissonance. It was expected that adolescents who report a certain category of delinquent behaviour would evaluate hypothetical transgressions in the same category as more non‐moral than would adolescents who did not report that category of delinquent behaviour. A group of 278 students from the first (M(age)=13.1), second (M(age)=14.3) and third (M(age)=15.2) grade of intermediate secondary schools in the Netherlands participated in the research. The results showed a domain shift from the moral towards non‐moral domains in the evaluation of hypothetical situations about delinquent behaviour reported by the adolescent. At the same time, this domain shift did not occur in situations concerning delinquent behaviour not reported by the adolescent, even when delinquent behaviour occurred in the adolescent's peer group. This finding is consistent with the hypothesis that the domain shift takes place as a consequence of cognitive dissonance. The results also showed that the attitude towards delinquent behaviour and the prevalence of delinquent behaviour in the peer group both predicted a unique part of the variance in reported delinquent behaviour (RDB; 28% and 10%, respectively). The level of moral reasoning (measured by the Sociomoral Reflection Measure–Short Form [SRM‐SF]) did not appear to be a significant predictor of RDB.     

Emotional stimuli facilitate time perception in children with attention‐deficit/hyperactivity disorder

The aim of this study was to compare the effect of different emotional stimuli (neutral, positive, and negative) on time perception in children with attention‐deficit/hyperactivity disorder (ADHD) and normal children in dual‐task form. Five hundred and ninety‐nine students from primary schools were randomly selected. The Conner's Teacher Rating Scale (CTRS) questionnaire was completed by teachers. A total of 100 children with a score above the cut‐off point for the CTRS were further assessed using the Child Symptom Inventory‐4 (CSI‐4). A total of 34 children with ADHD and 31 controls completed an emotional time discrimination task in two blocks of 1000 and 2000 ms duration. Children were asked to compare three image groups: neutral with neutral, neutral with positive, and neutral with negative images. Children with ADHD had significantly better performance in the emotional time discrimination task across all conditions when compared with controls: On average, discrimination thresholds were approximately 35 ms shorter for the children with ADHD. Our results indicate that children with ADHD have higher sensitivity to time relative to controls in a situation in which they must distribute resources between temporal and emotional processing. On the basis of the interference effect and the working memory capacity hypothesis, this dividing of attention causes a decrease of time accuracy in normal children.     

The association between persistent disruptive childhood behaviour and the psychopathic personality constellation in adolescence: A twin study

This study tested if persistent externalizing behaviour and symptoms of Attention Deficit Hyperactivity Disorder (ADHD) in childhood are associated with personality and behavioural aspects of the psychopathic personality constellation in adolescence. The target sample consisted of all 1,480 twin pairs born in Sweden between 1985 and 1986. Parent‐reported externalizing behaviour and ADHD symptoms were obtained when the participants were 8–9 and 13–14 years old. Personality and behavioural aspects of the psychopathic personality constellation were measured with self‐report questionnaires when the participants were 16–17 years old. Persistent externalizing behaviour in childhood was associated with both psychopathic personality and antisocial behaviour in adolescence. However, within twin‐pair analyses showed that genetic factors explained the association between persistent externalizing behaviour and psychopathic personality, while shared environmental factors explained the association between persistent externalizing and antisocial behaviours. We conclude that persistent externalizing behaviour is a genetically influenced precursor of psychopathic personality among boys.     

Effects of maternal stress on development and behaviour in rat offspring

Retrospective studies suggest that gestational stress in humans can delay the attainment of developmental milestones, increase the incidence of allergic reactions and respiratory infections and cause behavioural abnormalities in the children. Our studies and others have shown that prenatal stress in rats can mimic several of these developmental and behavioural alterations. These include a suppression of immune function, but also enhanced sensitivity to allergens. Prenatally-stressed rats, like children, show a reduced propensity for social interaction and increased anxiety in intimidating or novel situations. They have physiological and behavioural alterations consistent with depressive symptoms, including a phase-shift in their circadian rhythm for corticosterone, sleep abnormalities, and greater acquisition of learned helplessness under appropriate conditions. Prenatally-stressed male rats also show demasculinisation and feminisation of their sexual behaviour. The developmental and behavioural abnormalities in prenatally-stressed offspring may be mediated by alterations in the activity of endogenous opioids or neurosteroids, since several of them can be corrected by maternal administration of an opioid antagonist or by drugs like diazepam and allopregnanolone that modulate GABA transmission.     

A computerized test of self-control predicts classroom behavior

We assessed choices on a computerized test of self-control (CTSC) for a group of children with features of attention deficit hyperactivity disorder (ADHD) and a group of controls. Thirty boys participated in the study. Fifteen of the children had been rated by their parents as hyperactive and inattentive, and 15 were age- and gender-matched controls in the same classroom. The children were observed in the classroom for three consecutive mornings, and data were collected on their activity levels and attention. The CTSC consisted of two tasks. In the delay condition, children chose to receive three rewards after a delay of 60 s or one reward immediately. In the task-difficulty condition, the children chose to complete a difficult math problem and receive three rewards or complete an easier problem for one reward. The children with ADHD features made more impulsive choices than their peers during both conditions, and these choices correlated with measures of their activity and attention in the classroom.     

Temporal discounting of monetary rewards in children and adolescents with ADHD and autism spectrum disorders

It has been difficult to differentiate attention‐deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in terms of some aspects of their cognitive profile. While both show deficits in executive functions, it has been suggested that they may differ in their response to monetary reward. For instance, children with ADHD prefer small immediate over large delayed rewards more than typically developing controls. One explanation for this is that they discount the value of rewards to a higher degree as they are moved into the future. The current study investigated whether children with ADHD can be differentiated from those with ASD in terms of reward discounting. Thirty‐nine children (8–16 y) with ADHD, 34 children with ASD and 46 typically developing controls performed a hypothetical monetary temporal discounting task. Participants were instructed to make repeated choices between small variable rewards (0, 5, 10, 20, 30€) delivered immediately and large rewards delivered after a variable delay. Children with ADHD but not ASD discounted future rewards at a higher rate than typically developing controls. These data confirm steeper discounting of future rewards in ADHD and add to a small but growing literature showing that the psychological profile of ADHD can be distinguished from that of ASD in terms of disrupted motivational processes.     

Institutional care and iron deficiency increase ADHD symptomology and lower IQ 2.5–5 years post‐adoption

Increased ADHD symptomology and lower IQ have been reported in internationally adopted (IA) children compared to non‐adopted peers (Hostinar, Stellern, Schaefer, Carlson & Gunnar, 2012; Kreppner, O'Connor & Rutter, 2001). However, it is unclear whether these outcomes are due to institutional deprivation specifically or to co‐occurring micronutrient deficiencies that disrupt brain development (Fuglestad, Rao & Georgieff, 2008b). In this study, IA children were compared to children raised in their biological families to examine differences in ADHD symptomology and IQ 2.5–5 years post‐adoption and to assess the contributions of iron deficiency (ID) and duration of deprivation to these cognitive outcomes. ADHD symptoms (parent‐ and experimenter‐reported) and IQ were evaluated in 88 IA (M = 62.1 months, SD = 2.4) and 35 non‐adopted children (M = 61.4 months, SD = 1.6). IA children were assessed 29–64 months post‐adoption (M = 41.9 months, SD = 10.2). ID was assessed during the initial post‐adoption medical visit in 69 children, and children were classified into four groups by iron status, ranging from normal to ID anemia (most severe). IA children had greater ADHD symptomology, p < .01, and lower IQ, p = .001, than non‐adopted children. Within the IA group, children with more severe ID at adoption had greater ADHD symptomology, r(69) = 0.40, p = .001, and lower IQ, r(68) = −0.28, p < .05. Duration of institutional care was positively correlated with ADHD symptoms, r(86) = .28, p < .01, but not IQ, r(85) = −.08, p = .52. Longitudinal results indicate improvement in IQ from 12 months post‐adoption to age 5 for children with greater ID severity at adoption and longer duration of institutional care but no improvement in ADHD symptoms. These results signify continuing effects of early deprivation and ID on ADHD symptoms and IQ years after adoption. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=vUFDAS3DD1c     

Personality Mediation of Genetic Effects on Attention-Deficit/Hyperactivity Disorder

Personality traits may be viable candidates for mediators of the relationship between genetic risk and ADHD. Participants were 578 children (331 boys; 320 children with ADHD) between the ages of six and 18. Parents and teachers completed a comprehensive, multi-stage diagnostic procedure to assess ADHD and comorbid disorders. Mother completed the California Q-Sort to assess child Big Five personality traits. Children provided buccal samples of DNA which were assayed for selected markers on DRD4, DAT1, and ADRA2A. An additive genetic risk composite was associated with ADHD symptoms and maladaptive personality traits; maladaptive personality traits were associated with ADHD symptoms. Low conscientiousness and high neuroticism partially mediated the relationship between genetic risk and ADHD symptoms. Mediation effects for conscientiousness were specific to inattentive symptoms; effects for neuroticism generalized to all disruptive behaviors. High neuroticism and low conscientiousness may be useful as early markers for children at risk for ADHD.     

Strategic attention deployment for delay of gratification in working and waiting situations

Two studies examined whether the detrimental effects of attention to rewards on delay of gratification in waiting situations holds-or reverses-in working situations. In Study 1, preschoolers waited or worked for desired delayed rewards. Delay times increased when children worked in the presence of rewards but, as predicted, this increase was due to the distraction provided by the work itself. not because attention to rewards motivated children to sustain work. Analysis of spontaneous attention deployment showed that attending to rewards reduces delay time regardless of the working or waiting nature of the task. Fixing attention on rewards was a particularly detrimental strategy regardless of the type of task. Study 2 showed that when the work is not engaging, however, attention to rewards can motivate instrumental work and facilitate delay of gratification as long as attention deployment does not become fixed on the rewards.     

Antecedents of children's physical activity intentions and behaviour: Predictive validity and longitudinal effects

Abstract

This study examined the predictive validity and time-lagged relationships in a model of children's physical activity intentions, attitudes, perceived behavioural control (PBC), behaviour and past behaviour using the Theory of Planned Behaviour (TPB; Ajzen, 1985) as a framework. In Study 1, 386 children aged 12–14 years completed measures of intentions, attitudes, subjective norm, PBC and past behaviour. Their physical activity behaviour was assessed one week later. Structural equation analyses supported the construct and predictive validity of the TPB with the exception of subjective norms which did not predict intentions. In Study 2,70 children completed measures of their physical activity attitudes, intentions, PBC and past behaviour. Attitudes, intentions, PBC and recent behaviour were re-assessed five weeks later. The cognitions demonstrated a moderate degree of stability over time and there were some cross-lagged effects between attitudes and PBC. Past behaviour demonstrated additive rather than attenuating effects. These results support the use of the TPB cognitions and past behaviour as a framework to examine children's physical activity behaviour.     

Motor excitability is reduced prior to voluntary movements in children and adolescents with Tourette syndrome

Tourette syndrome (TS) is a neuro‐developmental disorder characterized by the occurrence of motor and vocal tics: involuntary, repetitive, stereotyped behaviours that occur with a limited duration, often typically many times in a single day. Previous studies suggest that children and adolescents with TS may undergo compensatory, neuroplastic changes in brain structure and function that help them gain control over their tics. In the current study we used single‐pulse and dual‐site paired‐pulse transcranial magnetic stimulation (TMS), in conjunction with a manual choice reaction time task that induces high levels of inter‐manual conflict, to investigate this conjecture in a group of children and adolescents with TS, but without co‐morbid Attention Deficit Hyperactivity Disorder (ADHD). We found that performance on the behavioural response‐conflict task did not differ between the adolescents with TS and a group of age‐matched typically developing individuals. By contrast, our study demonstrated that cortical excitability, as measured by TMS‐induced motor‐evoked potentials (MEPs), was significantly reduced in the TS group in the period immediately preceding a finger movement. This effect is interpreted as consistent with previous suggestions that the cortical hyper‐excitability that may give rise to tics in TS is actively suppressed by cognitive control mechanisms. Finally, we found no reliable evidence for altered patterns of functional inter‐hemispheric connectivity in TS. These results provide evidence for compensatory brain reorganization that may underlie the increased self‐regulation mechanisms that have been hypothesized to bring about the control of tics during adolescence.     

Time Reproduction in Children With ADHD: Motivation Matters

The primary goal of this study was to examine whether children with ADHD have a true deficit in subjective time sense, or whether their impairment reflects a motivational deficit. Thirty children with ADHD and 30 matched control children completed two versions of a time reproduction paradigm (“Regular” and “Enhanced”) in which motivational level was manipulated by the addition of positive sham feedback and the prospect of earning a reward. A secondary goal was to investigate performance on measures of working memory and behavioural inhibition, and how those constructs relate to time reproduction in the context of Barkley’s (1997a) model of ADHD. Children with ADHD performed significantly better on the motivating ‘Enhanced’ versus the Regular time reproduction paradigm, although they continued to perform significantly worse than controls on both tasks. Control children exhibited no reliable change in performance between versions of the task. Significant group differences were also observed on the working memory and behavioural inhibition tasks. We discuss the impact of motivation, working memory, and behavioural inhibition on time reproduction performance.