Choice-impulsivity in children and adolescents with attention-deficit/hyperactivity disorder (ADHD): A meta-analytic review

Methylphenidate increases willingness to perform effort in adults with ADHD

BACKGROUND

A reduced willingness to perform effort based on the magnitude and probability of potential rewards has been associated with diminished dopamine function and may be relevant to attention-deficit/hyperactivity disorder (ADHD). Here, we investigated the influence of ADHD status and methylphenidate on effort-based decisions. We hypothesized that ADHD participants would make fewer high-effort selections than non-ADHD subjects, and that methylphenidate would increase the number of high-effort selections. Furthermore, we hypothesized there would be associations among ADHD severity and methylphenidate-related changes in effort-based and attentional performance across all participants.

METHODS AND PARTICIPANTS

ADHD (n = 23) and non-ADHD (n = 23) adults completed the Effort Expenditure for Rewards Task in which participants select between low-effort and high-effort options to receive monetary rewards at varying levels of reward magnitude and probability. A test of attentional performance was also completed.

RESULTS

Overall, participants made more high-effort selections as potential reward magnitude and probability increased. ADHD participants did not make fewer high-effort selections than non-ADHD participants, but ADHD participants showed greater methylphenidate-related increases in high-effort selections. ADHD participants had worse attentional performance than non-ADHD participants. ADHD severity was associated with methylphenidate-related changes in high-effort selections, but not changes in attentional performance.

CONCLUSIONS

These results indicate that methylphenidate increases the willingness to perform effort in individuals with ADHD, possibly due to disorder-related motivational deficits. This provides support for theories of insufficient effort allocation among individuals with ADHD.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier, NCT02630017.

Effects of Exercise on Cognitive Performance in Children and Adolescents with ADHD: Potential Mechanisms and Evidence-based Recommendations

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with a complex symptomatology, and core symptoms as well as functional impairment often persist into adulthood. Recent investigations estimate the worldwide prevalence of ADHD in children and adolescents to be ~7%, which is a substantial increase compared to a decade ago. Conventional treatment most often includes pharmacotherapy with central nervous stimulants, but the number of non-responders and adverse effects call for treatment alternatives. Exercise has been suggested as a safe and low-cost adjunctive therapy for ADHD and is reported to be accompanied by positive effects on several aspects of cognitive functions in the general child population. Here we review existing evidence that exercise affects cognitive functions in children with and without ADHD and present likely neurophysiological mechanisms of action. We find well-described associations between physical activity and ADHD, as well as causal evidence in the form of small to moderate beneficial effects following acute aerobic exercise on executive functions in children with ADHD. Despite large heterogeneity, meta-analyses find small positive effects of exercise in population-based control (PBC) children, and our extracted effect sizes from long-term interventions suggest consistent positive effects in children and adolescents with ADHD. Paucity of studies probing the effect of different exercise parameters impedes finite conclusions in this regard. Large-scale clinical trials with appropriately timed exercise are needed. In summary, the existing preliminary evidence suggests that exercise can improve cognitive performance intimately linked to ADHD presentations in children with and without an ADHD diagnosis. Based on the findings from both PBC and ADHD children, we cautiously provide recommendations for parameters of exercise.

Low blood lead levels and attention-deficit hyperactivity disorder in children: a systematic review and meta-analysis

Attention-deficit hyperactivity disorder (ADHD) of children is one of the most common neurodevelopmental diseases; the etiology remains unclear. We reviewed and meta-analyzed case-control studies to assess the effects of blood lead levels in children on ADHD symptoms. Relevant studies were identified by searching electronic databases. A meta-analysis was performed using the fixed model of Review Manager 5.3 software. Seven relevant studies were identified. The case groups exhibited significant increases in ADHD symptoms [mean difference (MD), 0.59; 95% confidence interval (CI), 0.50-0.68; p < 0.0001]. Subgroup assessment showed that even children with blood lead levels <3 μg/dL exhibited significant increases in ADHD symptoms (MD, 0.47; 95% CI, 0.39-0.56; p < 0.0001). Subgroup assessment also showed that children aged 5-12 years exhibited more significant increases in ADHD symptoms (MD, 1.35; 95% CI, 0.28-2.41; p < 0.0001) than children aged >12 years. Our findings suggest that low blood lead levels may be associated with ADHD symptoms in children. However, caution is needed when interpreting the results because among-study heterogeneity was in play. Primary interventions should focus on children with low blood lead levels.

Prenatal testosterone exposure is associated with delay of gratification and attention problems/overactive behavior in 3-year-old boys

Sex differences in self-control become apparent during preschool years. Girls are better able to delay their gratification and show less attention problems and overactive behavior than boys. In this context, organizational effects of gonadal steroids affecting the neural circuitry underlying self-control could be responsible for these early sex differences. In the present study testosterone levels measured in amniotic fluid (via ultra performance liquid chromatography and tandem mass spectrometry) were used to examine the role of organizational sex hormones on self-control. One hundred and twenty-two 40-month-old children participated in a delay of gratification task (DoG task) and their parents reported on their attention problems and overactive behavior. Girls waited significantly longer for their preferred reward than boys, and significantly more girls than boys waited the maximum period of time, providing evidence for sex differences in delay of gratification. Boys that were rated as suffering from more attention problems and overactive behavior waited significantly shorter in the DoG task. Amniotic testosterone measures were reliable in boys only. Most importantly, boys who waited shorter in the DoG task and boys who were reported to suffer from more attention problems and overactive behavior had higher prenatal testosterone levels. These findings extend our knowledge concerning organizational effects of testosterone on the brain circuitry underlying self-control in boys, and are of relevance for understanding how sex differences in behavioral disorders are connected with a lack of self-control.

Brain structure and trait impulsivity: A comparative VBM study contrasting neural correlates of traditional and alternative concepts in healthy subjects

Impulsivity as a trait modulates a range of cognitive functions, e.g. planning, decision-making, or response inhibition. Recent behavioural and psychometric findings challenge both the neurobiological models as well as the conceptualisation of psychometric measures of impulsivity. In the present study, we aimed to test the association of brain structure with the Barratt Impulsiveness Scale (BIS-11), a commonly applied self-rating instrument for impulsivity, using both the classical three-factor-model for impulsive behaviour (motor (IM), attentional (IA) and non-planning impulsivity (INP)), as well as the recently proposed alternative model contrasting inability to wait for reward (IWR) as an index of impulsive choice and rapid response style (RRS) as an index of impulsive action. We analysed brain structural data in a community sample of 85 healthy individuals, who completed the BIS-11, using voxel-based morphometry (CAT12: Computational Anatomy Toolbox 12). Regional volumes were correlated with the three traditional BIS-11 subscales, as well as IWR and RRS. BIS-11 total score was positively correlated with right inferior parietal, postcentral, and supramarginal grey matter (p < 0.05, FWE cluster-level corrected). Attentional impulsivity (IA) was also positively correlated with right inferior and superior parietal and supramarginal gyri. Comparison of the other scales did show some divergence, but most correlations did not survive correction for multiple comparisons. Our findings suggest that difference facets of trait impulsivity might be related to different brain areas, and might thus dissociate along distinct but overlapping neural networks. In contrast to lesion or patient studies, these analyses delineate physiological variance, and can thus help to conceptualise network models in the absence of pathology.

Executive Functions in Girls With and Without Childhood ADHD Followed Through Emerging Adulthood: Developmental Trajectories

Using an all-female sample, we examined trajectories of executive functioning (EF) performance from childhood through emerging adulthood-and their prediction of key emerging-adult outcomes. One hundred forty girls carefully diagnosed with attention deficit/hyperactivity disorder (ADHD) and 88 matched comparison girls were administered EF measurements assessing global EF, response inhibition, and verbal working memory during childhood (M age = 9.5 years), adolescence (M age = 14.1 years), the earliest years of adulthood (M age = 19.6 years), and the end of emerging adulthood (M age = 25.6 years). Retention rates were excellent. Hierarchical linear modeling was used to estimate growth curves for each EF measure. The linear EF slopes were then used to explore how changes in EF interacted with each participant's persistence/remission of ADHD over time to influence behavioral, emotional, and academic impairment in emerging adulthood. Although all women experienced absolute improvements in EF performance across time, women with histories of ADHD consistently lagged behind comparison women, even if their ADHD symptoms had remitted by early adulthood. However, EF performance over time did not significantly influence the link between ADHD status and (a) maternal reports of associated behavioral and emotional impairment or (b) objective measures of academic achievement. These findings indicate that EF deficits should be considered when developing and implementing treatments for ADHD through emerging adulthood. Future research should be aimed at understanding the mechanisms behind these observed trajectory differences.

Optogenetic dissection of basolateral amygdala contributions to intertemporal choice in young and aged rats

Across species, aging is associated with an increased ability to choose delayed over immediate gratification. These experiments used young and aged rats to test the role of the basolateral amygdala (BLA) in intertemporal decision making. An optogenetic approach was used to inactivate the BLA in young and aged rats at discrete time points during choices between levers that yielded a small, immediate vs. a large, delayed food reward. BLA inactivation just prior to decisions attenuated impulsive choice in both young and aged rats. In contrast, inactivation during receipt of the small, immediate reward increased impulsive choice in young rats but had no effect in aged rats. BLA inactivation during the delay or intertrial interval had no effect at either age. These data demonstrate that the BLA plays multiple, temporally distinct roles during intertemporal choice, and show that the contribution of BLA to choice behavior changes across the lifespan.

Intergenerational transmission of delay discounting: The mediating role of household chaos

INTRODUCTION

Adolescence is a period when impulsive decision making may be especially vulnerable to environmental influences. Impulsive decision making is often assessed using a delay discounting paradigm, which measures the preference for smaller rewards sooner over larger rewards with a delay. Research is needed to clarify the relationship between parents' and adolescents' delay discounting and to identify related environmental processes that might facilitate the intergenerational transmission of delay discounting. The current prospective longitudinal study examined the competing mediating processes of household chaos and harsh parenting in the intergenerational transmission of delay discounting between parents and adolescents.

METHODS

Participants included 167 adolescents (mean age = 14.07 years at Time 1; 53% male) and their parents (mean age = 41.98 years at Time 1; 87% female) recruited from the southeast United States. Parents' delay discounting was collected at Time 1, and adolescents' delay discounting was collected both at Time 1 and at Time 3 via a computerized delay discounting task. Parents and adolescents reported household chaos and harsh parenting at Time 2.

RESULTS

A parallel mediation model indicated that parents' delay discounting at Time 1 indirectly predicted adolescents' delay discounting Time 3 residualized change scores (regressing Time 3 delay discounting onto baseline delay discounting) through household chaos but not through harsh parenting at Time 2.

CONCLUSIONS

These results underline the importance of household chaos in facilitating the intergenerational transmission of delay discounting between parents and adolescents. Furthermore, our findings point to household chaos as a potential environmental target for interrupting intergenerational impulsivity.

Prospective memory (partially) mediates the link between ADHD symptoms and procrastination

Individuals with attention deficit hyperactivity disorder (ADHD) often show poor planning and poor organization of tasks and activities which has been related to reduced memory for delayed intentions (prospective memory) and procrastination-in addition to other cognitive or motivational factors. This study set out to bring the fields of prospective memory and procrastination research together and to explore possible relations between the two constructs in ADHD. Twenty-nine adults with ADHD and 24 healthy controls performed several laboratory-based and real-life prospective memory tasks and filled in questionnaires measuring their symptom severity and procrastination behaviour. Overall, individuals' with ADHD showed clear deficits in everyday prospective memory performance. Individuals with ADHD recalled and executed less of their own real-life intentions. Moreover, there were clear links between everyday prospective memory performance and reported procrastination behaviour, and everyday prospective memory performance mediated the link between ADHD symptoms and procrastination behaviour.

Risk-Taking Behavior in Attention Deficit/Hyperactivity Disorder (ADHD): a Review of Potential Underlying Mechanisms and of Interventions

PURPOSE OF REVIEW

Attention deficit/hyperactivity disorder (ADHD) is associated with several forms of risk-taking behavior (RTB). This paper aims to examine the scope of ADHD-related RTB, to highlight potential underlying mechanisms of this association, and to review initial evidence for interventions aimed to treat ADHD-related RTB.

RECENT FINDINGS

Multiple lines of evidence indicate that ADHD is associated with real-life RTB across several domains (e.g., reckless driving, substance use, and unprotected sex), which is corroborated by evidence on laboratory risk-taking tasks. Several individual differences, some of them informed by decision theory, e.g., comorbid disorders, parental monitoring, and perceived enlarged benefits of RTB, may explain the link between ADHD and RTB. A number of studies showed that interventions designed for ADHD may reduce RTB. ADHD is linked to RTB across several domains. Decision theory may serve as a conceptual framework for understanding the underlying mechanisms, and thus may inform future research.

Development of the frontal lobe

Development of the frontal lobe is critical to acquisition, execution, and control of a wide range of functions, from basic motor response to complex decision-making. These functions are influenced by contingency-based (e.g., reward and response-cost/punishment) feedback that is mediated through the adaptive integration of fronto-subcortical neural circuitry. The frontal lobe manages incoming information and chooses the appropriate action based on one's goals in a particular context. This aspect of frontal function, while only one component, is crucial to development and maintenance of approach and avoidance behavior central to all human (and animal) behavior. Furthermore, disruptions in fronto-subcortical circuitry governing motivated behavior appear to contribute to a range of developmental disorders, including attention-deficit/hyperactivity disorder (ADHD), and confer vulnerability for psychopathology more broadly. The particular deficits that manifest in altered behavior depend upon the specific circuitry that is compromised due to the functional specificity of distinct regions of the frontal lobe and its interconnections with subcortical structures. Neurobiologic models of motivated behavior provide a valuable framework for characterizing developmental disorders from a transdiagnostic dimensional systems perspective. Improved characterization of approach and avoidance motivation across neurodevelopmental disorders has the potential to inform the development of novel interventions and personalized medicine.

ADHD-related sex differences in fronto-subcortical intrinsic functional connectivity and associations with delay discounting

Background

Attention-deficit/hyperactivity disorder (ADHD) is associated with atypical fronto-subcortical neural circuitry and heightened delay discounting, or a stronger preference for smaller, immediate rewards over larger, delayed rewards. Recent evidence of ADHD-related sex differences in brain structure and function suggests anomalies in fronto-subcortical circuitry may differ among girls and boys with ADHD. The current study examined whether the functional connectivity (FC) within fronto-subcortical neural circuitry differs among girls and boys with ADHD compared to same-sex typically developing (TD) controls and relates to delay discounting.

Methods

Participants include 8–12-year-old children with ADHD (n = 72, 20 girls) and TD controls (n = 75, 21 girls). Fronto-subcortical regions of interest were functionally defined by applying independent component analysis to resting-state fMRI data. Intrinsic FC between subcortical components, including the striatum and amygdala, and prefrontal components, including ventromedial prefrontal cortex (vmPFC), anterior cingulate cortex (ACC), and anterior dorsolateral prefrontal cortex (dlPFC), was compared across diagnostic groups overall and within sex. Correlations between intrinsic FC of the six fronto-subcortical pairs and delay discounting were also examined.

Results

Both girls and boys with ADHD show atypical FC between vmPFC and subcortical regions including the striatum (stronger positive FC in ADHD) and amygdala (weaker negative FC in ADHD), with the greatest diagnostic effects among girls. In addition, girls with ADHD show atypical intrinsic FC between the striatum and dlPFC components, including stronger positive FC with ACC and stronger negative FC with dlPFC. Further, girls but not boys, with ADHD, show heightened real-time delay discounting. Brain–behavior correlations suggest (1) stronger negative FC between the striatal and dlPFC components correlated with greater money delay discounting across all participants and (2) stronger FC between the amygdala with both the dlPFC and ACC components was differentially related to heightened real-time discounting among girls and boys with and without ADHD.

Conclusions

Our findings suggest fronto-subcortical functional networks are affected in children with ADHD, particularly girls, and relate to delay discounting. These results also provide preliminary evidence of greater disruptions in fronto-subcortical FC among girls with ADHD that is not due to elevated inattention symptom severity, intellectual reasoning ability, age, or head motion.

Electronic supplementary material

The online version of this article (10.1186/s11689-018-9254-9) contains supplementary material, which is available to authorized users.

The Neurocognitive Profile of Attention-Deficit/Hyperactivity Disorder: A Review of Meta-Analyses

Objective

Numerous meta-analyses have summarized studies comparing the neurocognitive performance of individuals with attention-deficit/hyperactivity disorder (ADHD) to that of healthy controls.

Method

The present study is a systematic review and quantitative summary of those meta-analyses that aimed to determine the extent to which individuals with ADHD differ cognitively from typically developing controls.

Results

Of 253 standardized mean differences (SMDs) drawn from 34 meta-analyses, 244 (96%) were positive, indicating better neurocognitive performance in the control group than the ADHD group. The mean effect size was .45 (SD = .27). Unweighted means of SMDs for neurocognitive domains ranged from .35 (set shifting) to .54 (working memory). When weighted by the number of studies aggregated, they ranged from .35 (set shifting) to .66 (reaction time variability). Neurocognitive domains with mean effects over .50 included working memory (.54), reaction time variability (.53), response inhibition (.52), intelligence/achievement (.51), and planning/organization (.51). When weighted by number of aggregated studies, the domains with mean effects over .50 were reaction time variability (.66), intelligence/achievement (.60), vigilance (.56), working memory (.54), and response inhibition (.52). Age moderated the relationship between ADHD diagnosis and neurocognitive functioning, with greater between-groups differences among children and adults than among adolescents. Funding also moderated this relationship: meta-analyses that received drug funding found larger effect sizes than those without drug funding.

Conclusions

The evidence suggests that ADHD is associated with substantial deficits across a variety of neurocognitive domains. This is the most in-depth review of the neurocognitive functioning of people with ADHD to date.

Temporal discounting and attention-deficit/hyperactivity disorder in childhood: reasons for devising different tasks

INTRODUCTION

Temporal discounting (TD) describes how a certain reward is seen as less valuable the more its delivery is postponed. There are two main types of TD tasks, hypothetical and real, both of which use monetary rewards. Over the last few years, however, variants of these tasks have been adjusted to assess clinical groups of children showing impulsivity as found in attention-deficit/hyperactivity disorder (ADHD).

OBJECTIVE

To review and discuss studies conducted over the last 10 years on the use of TD tasks in the assessment of pediatric patients with ADHD.

METHOD

For this literature review, articles were non-systematically selected from PubMed, MEDLINE and SciELO databases to include experimental studies on the use of at least one TD paradigm to assess and distinguish ADHD and non-ADHD groups.

RESULTS

Of the studies assessed, 76.19% used hypothetical tasks, followed by real tasks (28.57%), and, finally, tasks using different types of reward, such as toys or rewarding activities (14.28%).

CONCLUSIONS

Although assessed in few studies, real and alternative tasks appeared to be effective in differentiating clinical groups and suitable for investigating hot executive functions in childhood.

5-HT3 antagonists decrease discounting rate without affecting sensitivity to reward magnitude in the delay discounting task in mice

RATIONALE

Impulsive choice has often been evaluated in rodents according to the proportion of choices for the delayed large magnitude reinforcer (%large choice) in a delay-discounting task (DDT). However, because %large choice is influenced by both sensitivity to reinforcer magnitude and sensitivity to delayed reinforcement (i.e., discounting rate), distinctively evaluating such discounting parameters represents a critical issue demanding methods to determine each parameter in rats. The serotonin (5-HT) system is well known to be involved in impulsive choice; nevertheless, only a few studies have distinguished discounting parameters and investigated how 5-HT modulators affect discounting rate.

OBJECTIVE

Here, we performed a discounting parameter analysis in mice and examined the effects of various 5-HT modulators on discounting rate.

METHODS

We set up DDTs with different delay schedules to determine which schedule could address delay-discounting rates in mice. We examined the effect of the following drugs on impulsive choice: a 5-HT reuptake inhibitor (paroxetine), a 5-HT_1A receptor agonist (8-OH-DPAT), and two 5-HT₃ receptor antagonists (granisetron and ondansetron).

RESULTS

Mice showed typical delay discounting at the shorter delay schedules (up to 4 s delay). The %large choice under shorter, but not longer, schedules followed an exponential function and allowed us to derive discounting rates. We selected a DDT with a 4-s delay schedule for further experiments. Granisetron and ondansetron, but not paroxetine or 8-OH-DPAT, decreased discounting rates without affecting sensitivity to reinforcer magnitude.

CONCLUSION

We found that a method to calculate discounting rates in rats is also applicable to mouse models. We also provided evidence that 5-HT₃ antagonism controls impulsive choice in mice.

Delay Aversion and Executive Functioning in Adults With Attention-Deficit/Hyperactivity Disorder: Before and After Stimulant Treatment

BACKGROUND

Attention deficit hyperactivity disorder is a heterogeneous disorder, associated with deficits in motivation (e.g., delay aversion) and cognition. Methylphenidate is recommended as a first line treatment for attention deficit hyperactivity disorder symptoms, but little is known about its nonacute effects on motivational and cognitive deficits, particularly in adults with attention deficit hyperactivity disorder.

METHODS

We utilized a prospective, non-randomized, non-blinded, 6-week follow-up design with 42 initially stimulant medication-naïve adult patients with moderate to severe attention deficit hyperactivity disorder, and 42 age- and parental education-matched healthy controls. Delay aversion and executive functioning were assessed with 2 questionnaires and 5 performance-based tests.

RESULTS

At baseline, patients and controls differed significantly on performance-based measures (moderate to large effect sizes), and self-report of delay aversion and executive functioning (very large effect sizes). Treatment with methylphenidate medication (mean dose 65.54 mg/d, SD=10.39) was not associated with improvements in performance-based measures of delay aversion and executive functioning compared to controls, although improvements in self-report executive functioning and delay aversion were found. Self-reported delay aversion was most consistently associated with ADHD symptomatology at baseline and after medication.

CONCLUSION

Methylphenidate treatment does not have an effect on performance-based measures of delay aversion and executive functioning, but may have significant effects on self-reported delay aversion and executive functioning. The latter finding should be interpreted cautiously, given the subjective nature of these measures and design limitations. Self-reported delay aversion is most consistently associated with attention deficit hyperactivity disorder symptomatology.

Delay discounting of monetary gains and losses in adolescents with ADHD: Contribution of delay aversion to choice

Adolescents with attention-deficit/hyperactivity disorder (ADHD) are known to have stronger preferences for smaller immediate rewards over larger delayed rewards in delay discounting tasks than their peers, which has been argued to reflect delay aversion. Here, participants performed a delay discounting task with gains and losses. In this latter condition, participants were asked whether they were willing to wait in order to lose less money. Following the core assumption of the delay aversion model that individuals with ADHD have a general aversion to delay, one would predict adolescents with ADHD to avoid waiting in both conditions. Adolescents (12-17 years) with ADHD (n = 29) and controls (n = 28) made choices between smaller immediate and larger delayed gains, and between larger immediate and smaller delayed losses. All delays (5-25 s) and gains/losses (2-10 cents) were experienced. In addition to an area under the curve approach, a mixed-model analysis was conducted to disentangle the contributions of delay duration and immediate gain/delayed loss amount to choice. The ADHD group chose the immediate option more often than controls in the gain condition, but not in the loss condition. The contribution of delay duration to immediate choices was stronger for the ADHD group than the control group in the gain condition only. In addition, the ADHD group scored higher on self-reported delay aversion, and delay aversion was associated with delay sensitivity in the gain condition, but not in the loss condition. In sum, we found no clear evidence for a general aversion to delay in adolescents with ADHD.

A Review of the Clinical Utility of Systematic Behavioral Observations in Attention Deficit Hyperactivity Disorder (ADHD)

This review evaluates the clinical utility of tools for systematic behavioral observation in different settings for children and adolescents with ADHD. A comprehensive search yielded 135 relevant results since 1990. Observations from naturalistic settings were grouped into observations of classroom behavior (n = 58) and of social interactions (n = 25). Laboratory observations were subdivided into four contexts: independent play (n = 9), test session (n = 27), parent interaction (n = 11), and peer interaction (n = 5). Clinically relevant aspects of reliability and validity of employed instruments are reviewed. The results confirm the usefulness of systematic observations. However, no procedure can be recommended as a stand-alone diagnostic method. Psychometric properties are often unsatisfactory, which reduces the validity of observational methods, particularly for measuring treatment outcome. Further efforts are needed to improve the specificity of observational methods with regard to the discrimination of comorbidities and other disorders.

Reduced Value-Driven Attentional Capture Among Children with ADHD Compared to Typically Developing Controls

The current study examined whether children with ADHD were more distracted by a stimulus previously associated with reward, but currently goal-irrelevant, than their typically-developing peers. In addition, we also probed the associated cognitive and motivational mechanisms by examining correlations with other behavioral tasks. Participants included 8-12 year-old children with ADHD (n = 30) and typically developing controls (n = 26). Children were instructed to visually search for color-defined targets and received monetary rewards for accurate responses. In a subsequent search task in which color was explicitly irrelevant, we manipulated whether a distractor item appeared in a previously reward-associated color. We examined whether children responded more slowly on trials with the previously-rewarded distractor present compared to trials without this distractor, a phenomenon referred to as value-driven attentional capture (VDAC), and whether children with and without ADHD differed in the extent to which they displayed VDAC. Correlations among working memory performance, immediate reward preference (delay discounting) and attentional capture were also examined. Children with ADHD were significantly less affected by the presence of the previously rewarded distractor than were control participants. Within the ADHD group, greater value-driven attentional capture was associated with poorer working memory. Although both ADHD and control participants were initially distracted by previously reward-associated stimuli, the magnitude of distraction was larger and persisted longer among control participants.

Waiting and working for rewards: Attention-Deficit/Hyperactivity Disorder is associated with steeper delay discounting linked to amygdala activation, but not with steeper effort discounting

OBJECTIVE

Children and adolescents with ADHD have a relatively strong preference for smaller immediate rewards over larger delayed rewards (steep delay discounting). It is unknown whether such steep discounting of rewards is specific for delayed rewards, i.e., supporting the delay aversion account of ADHD, or whether it is also present for effortful rewards, i.e., representing general reward insensitivity. Therefore, this study examined behavioral and BOLD responses during delay discounting (DD) and effort discounting (ED) in ADHD.

METHOD

Thirty adolescents with ADHD and 28 controls (12-17 years) were scanned while performing a DD-ED task (fMRI findings were based on 21 and 25 participants, respectively). During DD, participants were presented with a series of choices between a small reward delivered immediately and a larger reward delivered after 5-25s. During ED, participants were presented with choices between a small reward that was delivered after exerting 15% of their maximal hand grip strength and a larger reward delivered after exerting 30-90% of their strength.

RESULTS

Analyses on the subjective values of delayed and effortful rewards and on the Area Under the discounting Curves (AUCs) indicated that adolescents with ADHD showed steeper discounting than controls for DD, but not for ED. This was accompanied by a slightly stronger delay dose-response relationship in the amygdala for adolescents with ADHD who reported to be more delay averse in daily life.

CONCLUSION

Together, these results-steeper DD in the ADHD group and a stronger delay dose-response relationship in the amygdala, while no evidence for group differences in ED was found-support the delay aversion account of ADHD.

Preliminary evidence of altered neural response during intertemporal choice of losses in adult attention-deficit hyperactivity disorder

Impulsive behaviours are common symptoms of attention-deficit hyperactivity disorder (ADHD). Although previous studies have suggested functional models of impulsive behaviour, a full explanation of impulsivity in ADHD remains elusive. To investigate the detailed mechanisms behind impulsive behaviour in ADHD, we applied an economic intertemporal choice task involving gains and losses to adults with ADHD and healthy controls and measured brain activity by functional magnetic resonance imaging. In the intertemporal choice of future gains, we observed no behavioural or neural difference between the two groups. In the intertemporal choice of future losses, adults with ADHD exhibited higher discount rates than the control participants. Furthermore, a comparison of brain activity representing the sensitivity of future loss in the two groups revealed significantly lower activity in the striatum and higher activity in the amygdala in adults with ADHD than in controls. Our preliminary findings suggest that an altered size sensitivity to future loss is involved in apparent impulsive choice behaviour in adults with ADHD and shed light on the multifaceted impulsivity underlying ADHD.

Ventral Striatal D2/3 Receptor Availability Is Associated with Impulsive Choice Behavior As Well As Limbic Corticostriatal Connectivity

BACKGROUND

Low dopamine D2/3 receptor availability in the nucleus accumbens shell is associated with highly impulsive behavior in rats as measured by premature responses in a cued attentional task. However, it is unclear whether dopamine D2/3 receptor availability in the nucleus accumbens is equally linked to intolerance for delayed rewards, a related form of impulsivity.

METHODS

We investigated the relationship between D2/3 receptor availability in the nucleus accumbens and impulsivity in a delay-discounting task where animals must choose between immediate, small-magnitude rewards and delayed, larger-magnitude rewards. Corticostriatal D2/3 receptor availability was measured in rats stratified for high and low impulsivity using in vivo [18F]fallypride positron emission tomography and ex vivo [3H]raclopride autoradiography. Resting-state functional connectivity in limbic corticostriatal networks was also assessed using fMRI.

RESULTS

Delay-discounting task impulsivity was inversely related to D2/3 receptor availability in the nucleus accumbens core but not the dorsal striatum, with higher D2/3 binding in the nucleus accumbens shell of high-impulsive rats compared with low-impulsive rats. D2/3 receptor availability was associated with stronger connectivity between the cingulate cortex and hippocampus of high- vs low-impulsive rats.

CONCLUSIONS

We conclude that delay-discounting task impulsivity is associated with low D2/3 receptor binding in the nucleus accumbens core. Thus, two related forms of waiting impulsivity-premature responding and delay intolerance in a delay-of-reward task-implicate an involvement of D2/3 receptor availability in the nucleus accumbens shell and core, respectively. This dissociation may be causal or consequential to enhanced functional connectivity of limbic brain circuitry and hold relevance for attention-deficit/hyperactivity disorder, drug addiction, and other psychiatric disorders.

Early Childhood Adverse Experiences, Inferior Frontal Gyrus Connectivity, and the Trajectory of Externalizing Psychopathology

OBJECTIVE

Early adverse childhood experiences (ACEs) have been linked to the development of both internalizing and externalizing psychopathology. In our prior work, we found that ACEs predicted reductions in the volume of the inferior frontal gyrus (IFG), a brain region important for impulse control and emotion regulation. Here we tested the hypothesis that ACEs might influence child behavioral outcomes through an impact on IFG functional connectivity, which may influence impulsive or risk-taking behavior.

METHOD

We examined the effects of prospectively assessed ACEs on IFG connectivity in childhood, and their relationship to the trajectory of subsequent psychopathology from late school age and early adolescence, using data from an 11-year longitudinal study of children starting in preschool that included 3 waves of resting state functional connectivity across childhood and early adolescence.

RESULTS

ACEs predicted functional connectivity of both left and right IFG. Multi-level modeling of symptoms across 3 waves of assessments indicated that more ACEs predicted both internalizing and externalizing symptoms. However, altered IFG connectivity specifically predicted greater externalizing symptoms over time in middle childhood and early adolescence, as compared to internalizing symptoms. Longitudinal modeling indicating that the relationships between externalizing and functional connectivity were maintained across 3 waves of functional connectivity assessment.

CONCLUSION

These findings underscore the relationship of ACEs to later psychopathology, and suggest that connectivity of the IFG, a region known to play an important role in impulse control and emotion regulation, may play a key role in the risk trajectory of ACEs to externalizing problems. However, further work is needed to understand whether these relationships reflect a direct effect of ACEs or whether ACEs are a marker for other environmental or genetic factors that may also influence brain development and behavior.

Systemic administration of guanfacine improves food-motivated impulsive choice behavior primarily via direct stimulation of postsynaptic α2A-adrenergic receptors in rats

Impulsive choice behavior, which can be assessed using the delay discounting task, is a characteristic of various psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD). Guanfacine is a selective α_2A-adrenergic receptor agonist that is clinically effective in treating ADHD. However, there is no clear evidence that systemic guanfacine administration reduces impulsive choice behavior in the delay discounting task in rats. In the present study, we examined the effect of systemic guanfacine administration on food-motivated impulsive choice behavior in rats and the neuronal mechanism underlying this effect. Repeated administration of either guanfacine, methylphenidate, or atomoxetine significantly enhanced impulse control, increasing the number of times the rats chose a large but delayed reward in a dose-dependent manner. The effect of guanfacine was significantly blocked by pretreatment with an α_2A-adrenergic receptor antagonist. Furthermore, the effect of guanfacine remained unaffected in rats pretreated with a selective noradrenergic neurotoxin, consistent with a post-synaptic action. In contrast, the effect of atomoxetine on impulsive choice behavior was attenuated by pretreatment with the noradrenergic neurotoxin. These results provide the first evidence that systemically administered guanfacine reduces impulsive choice behavior in rats and that direct stimulation of postsynaptic, rather than presynaptic, α_2A-adrenergic receptors is involved in this effect.

Response time scores on a reflexive attention task predict a child's inattention score from a parent report

Compared to sustained attention, only a small proportion of studies examine reflexive attention as a component of everyday attention. Understanding the significance of reflexive attention to everyday attention may inform better treatments for attentional disorders. Children from a general population (recruited when they were from 9-16 years old) completed an exogenously-cued task measuring the extent to which attention is captured by peripheral cue-target conditions. Parents completed a questionnaire reporting their child's day-to-day attention. A general linear model indicated that parent-rated inattention predicted the increase in response time over baseline when a bright cue preceded the target (whether it was valid or invalid) but not when a dim cue preceded the target. More attentive children had more pronounced response time increases from baseline. Our findings suggest a link between a basic measure of cognition (response time difference scores) and parent observations. The findings have implications for increased understanding of the role of reflexive attention in the everyday attention of children.

Genome-wide association study of delay discounting in 23,217 adult research participants of European ancestry

Delay discounting (DD), the tendency to discount the value of delayed versus current rewards, is elevated in a constellation of diseases and behavioral conditions. We performed a genome-wide association study of DD using 23,127 research participants of European ancestry. The most significantly associated single-nucleotide polymorphism was rs6528024 (P = 2.40 × 10-8), which is located in an intron of the gene GPM6B. We also showed that 12% of the variance in DD was accounted for by genotype and that the genetic signature of DD overlapped with attention-deficit/hyperactivity disorder, schizophrenia, major depression, smoking, personality, cognition and body weight.

Attention-Deficit/Hyperactivity Disorder Symptoms Are Associated with Overeating with and without Loss of Control in Youth with Overweight/Obesity

BACKGROUND

There is growing evidence that attention-deficit/hyperactivity disorder (ADHD) and loss of control (LOC) eating, both prevalent in children and adolescents, may be related to one another. However, the relationship between ADHD and overeating without LOC has been largely unexamined, thus precluding an understanding of the independent contributions of LOC and episode size in these associations. The current study sought to examine associations between ADHD symptoms and maladaptive eating by evaluating three different types of eating episodes characterized by the presence/absence of LOC and the amount of food consumed: objectively large LOC episodes [objective binge eating (OBE)], subjectively large binge episodes [subjective binge eating (SBE)], and objectively large overeating episodes without LOC [objective overeating (OO)].

METHODS

Participants were 385 youth (M age = 10.89, SD = 2.25) drawn from five different research protocols at institutions across the United States. Participants and their parents completed questionnaires and semistructured interviews to assess ADHD symptoms, OBE, SBE, and OO.

RESULTS

As hypothesized, negative binomial regressions revealed that ADHD symptoms were significantly associated with OBE, χ²(1) = 16.61, p < 0.001, and with OO, χ²(1) = 10.64, p < 0.01. Contrary to expectations, they were not associated with SBE.

CONCLUSIONS

These results indicate the need for future studies to explore possible shared mechanisms (e.g., impulsivity) underlying associations between ADHD symptoms, OBE, and OO. Clinical implications include support for considering ADHD symptoms in programs that target both prevention of LOC eating and obesity more generally.

Neural dysfunction during temporal discounting in paediatric Attention-Deficit/Hyperactivity Disorder and Obsessive-Compulsive Disorder

Both Attention-Deficit/Hyperactivity Disorder (ADHD) and Obsessive-Compulsive Disorder (OCD) are associated with choice impulsivity, i.e. the tendency to prefer smaller immediate rewards over larger delayed rewards. However, the extent to which this impulsivity is mediated by shared or distinct underlying neural mechanisms is unclear. Twenty-six boys with ADHD, 20 boys with OCD and 20 matched controls (aged 12-18) completed an fMRI version of an individually adjusted temporal discounting (TD) task which requires choosing between a variable amount of money now or £100 in one week, one month or one year. Activations to immediate and delayed reward choices were compared between groups using a three-way ANCOVA. ADHD patients had steeper discounting rates on the task relative to controls. OCD patients did not differ from controls or patients with ADHD. Patients with ADHD and OCD showed predominantly shared activation deficits during TD in fronto-striato-insular-cerebellar regions responsible for self-control and temporal foresight, suggesting that choice impulsivity is mediated by overlapping neural dysfunctions in both disorders. OCD patients alone showed dysfunction relative to controls in right orbitofrontal and rostrolateral prefrontal cortex, extending previous findings of abnormalities in these regions in OCD to the domain of choice impulsiveness.

Greater delay discounting among girls, but not boys, with ADHD correlates with cognitive control

Cognitive neuroscience models suggest both reward valuation and cognitive control contribute to reward-based decision-making. The current study examined the relationship between cognitive control and delay discounting (i.e., choosing smaller, immediate over larger, delayed rewards) in a large sample of boys and girls diagnosed with attention-deficit/hyperactivity disorder (ADHD; N = 95) and typically developing control children (TD; N = 59). Specifically, we examined performance on multiple measures of cognitive control (i.e., Go/No-Go task, Stop Signal task, and Spatial Span task) and delay discounting (i.e., Classic Delay Discounting and Real-Time Delay Discounting tasks), as well as the relationship between these measures. Results indicated that sex moderated the effects of group on task performance. Specifically, girls with ADHD, but not boys with the disorder, exhibited atypical delay discounting of real-time rewards. Results from correlational analyses indicated that delay discounting and cognitive control were not significantly correlated in the overall sample. Multiple regression analyses demonstrated that among girls with ADHD poorer spatial working memory and inhibitory control predicted greater real-time discounting. Collectively, findings provide support for distinct patterns of cognitive control and delay discounting among school-aged girls and boys with ADHD. Additionally, findings suggest that among girls with ADHD, those who exhibit relatively poor working memory and inhibitory control might be a particularly vulnerable subgroup with the greatest propensity to exhibit maladaptive decision-making.

Validation of the short Arabic UPPS-P Impulsive Behavior Scale

BACKGROUND

Impulsivity is involved in numerous psychiatric and addictive disorders, as well as in risky behaviors. The UPPS-P scale highlights five complementary impulsivity constructs (i.e., positive urgency, negative urgency, lack of perseverance, lack of premeditation, and sensation seeking) that possibly work as different pathways linking impulsivity to other disorders. In this study, we aimed to evaluate the psychometric properties of the Arab language short 20-item UPPS-P scale and to eventually validate it.

METHODS

Participants were recruited online through e-mail invitations. After online informed consent was obtained, the questionnaires (the UPPS-P and the Compulsive Internet Use Scale [CIUS]) were completed anonymously. The five dimensions of the Arab UPPS-P model were assessed in a sample of 743 participants.

RESULTS

As in other linguistic assessments of the UPPS-P, confirmatory factor analysis showed the validity of a model with five different, but nonetheless interrelated, facets of impulsivity. A three-factor model with two higher order factors-urgency (negative and positive) and lack of conscientiousness (lack of premeditation and lack of perseverance)-and a third sensation seeking factor fit the data well, but to a lesser extent. The results suggested good internal consistency, with external validity shown from correlations between some of the UPPS-P components and a measure of addictive Internet use (the CIUS).

CONCLUSION

The Arab short UPPS-P is a valid assessment tool with good psychometric properties and is suitable for online use.

Attention-deficit/hyperactivity disorder, delay discounting, and risky financial behaviors: A preliminary analysis of self-report data

Delay discounting-often referred to as hyperbolic discounting in the financial literature-is defined by a consistent preference for smaller, immediate rewards over larger, delayed rewards, and by failure of future consequences to curtail current consummatory behaviors. Previous research demonstrates (1) excessive delay discounting among individuals with attention-deficit/hyperactivity disorder (ADHD), (2) common neural substrates of delay discounting and hyperactive-impulsive symptoms of ADHD, and (3) associations between delay discounting and both debt burden and high interest rate borrowing. This study extends prior research by examining associations between ADHD symptoms, delay discounting, and an array of previously unevaluated financial outcomes among 544 individuals (mean age 35 years). Controlling for age, income, sex, education, and substance use, ADHD symptoms were associated with delay discounting, late credit card payments, credit card balances, use of pawn services, personal debt, and employment histories (less time spent at more jobs). Consistent with neural models of reward processing and associative learning, more of these relations were attributable to hyperactive-impulsive symptoms than inattentive symptoms. Implications for financial decision-making and directions for future research are discussed.

Neural mechanisms of individual differences in temporal discounting of monetary and primary rewards in adolescents

Adolescents are generally characterized as impulsive. However, impulsivity is a multi-dimensional construct that involves multiple component processes. Which of these components contribute to adolescent impulsivity is currently unclear. This study focused on the neural mechanisms underlying individual differences in distinct components of temporal discounting (TD), i.e., the preference for smaller immediate rewards over larger delayed rewards. Participants were 58 adolescents (12-16 years-old) who performed an fMRI TD task with both monetary and snack rewards. Using mixed-effects modeling, we determined participants' average impatience, and further decomposed TD choices into: 1) amount sensitivity (unique contribution of the magnitude of the immediate reward); and 2) delay sensitivity (unique contribution of delay duration). Adolescents' average impatience was positively correlated with frontoparietal and ventral striatal activity during delayed reward choices, and with ventromedial prefrontal cortex activity during immediate reward choices. Adolescents' amount sensitivity was positively associated with ventral striatal and dorsal anterior cingulate cortex activity during immediate reward choices. Delay sensitivity was positively correlated with inferior parietal cortex activity during delayed reward choices. As expected, snacks were discounted more steeply than money, and TD of both reward types was associated with overlapping activation in the inferior parietal cortex. Exploring whether testosterone or estradiol were associated with TD and its neural correlates revealed no significant associations. These findings indicate that distinct components contribute uniquely to TD choice and that individual differences in amount sensitivity are uniquely associated with activation of reward valuation areas, while individual differences in delay sensitivity are uniquely associated with activation of cognitive control areas.

Annual Research Review: On the relations among self-regulation, self-control, executive functioning, effortful control, cognitive control, impulsivity, risk-taking, and inhibition for developmental psychopathology

BACKGROUND

Self-regulation (SR) is central to developmental psychopathology, but progress has been impeded by varying terminology and meanings across fields and literatures.

METHODS

The present review attempts to move that discussion forward by noting key sources of prior confusion such as measurement-concept confounding, and then arguing the following major points.

RESULTS

First, the field needs a domain-general construct of SR that encompasses SR of action, emotion, and cognition and involves both top-down and bottom-up regulatory processes. This does not assume a shared core process across emotion, action, and cognition, but is intended to provide clarity on the extent of various claims about kinds of SR. Second, top-down aspects of SR need to be integrated. These include (a) basic processes that develop early and address immediate conflict signals, such as cognitive control and effortful control (EC), and (b) complex cognition and strategies for addressing future conflict, represented by the regulatory application of complex aspects of executive functioning. Executive function (EF) and cognitive control are not identical to SR because they can be used for other activities, but account for top-down aspects of SR at the cognitive level. Third, impulsivity, risk-taking, and disinhibition are distinct although overlapping; a taxonomy of the kinds of breakdowns of SR associated with psychopathology requires their differentiation. Fourth, different aspects of the SR universe can be organized hierarchically in relation to granularity, development, and time. Low-level components assemble into high-level components. This hierarchical perspective is consistent across literatures.

CONCLUSIONS

It is hoped that the framework outlined here will facilitate integration and cross-talk among investigators working from different perspectives, and facilitate individual differences research on how SR relates to developmental psychopathology.

Investigating the Impact of Cognitive Load and Motivation on Response Control in Relation to Delay Discounting in Children with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is characterized by deficits in impulse control across a range of behaviors, from simple actions to those involving complex decision-making (e.g., preference for smaller-sooner versus larger later rewards). This study investigated whether changes in motor response control with increased cognitive load and motivational contingencies are associated with decision-making in the form of delay discounting among 8-12 year old children with and without ADHD. Children with ADHD (n = 26; 8 girls) and typically developing controls (n = 40; 11 girls) completed a standard go/no-go (GNG) task, a GNG task with motivational contingencies, a GNG task with increased cognitive load, and two measures of delay discounting: a real-time task in which the delays and immediately consumable rewards are experienced in real-time, and a classic task involving choices about money at longer delays. Children with ADHD, particularly girls, exhibited greater delay discounting than controls during the real-time discounting task, whereas diagnostic groups did not significantly differ on the classic discounting task. The effect of cognitive load on response control was uniquely associated with greater discounting on the real-time task for children with ADHD, but not for control children. The effect of motivational contingencies on response control was not significantly associated with delay discounting for either diagnostic group. The findings from this study help to inform our understanding of the factors that influence deficient self-control in ADHD, suggesting that impairments in cognitive control may contribute to greater delay discounting in ADHD.

Hyperactivity in boys with attention-deficit/hyperactivity disorder: The influence of underlying visuospatial working memory and self-control processes

Changes in motor activity were examined across control and executive function (EF) tasks that differ with regard to demands placed on visuospatial working memory (VS-WM) and self-control processes. Motor activity was measured via actigraphy in 8- to 12-year-old boys with (n=15) and without (n=17) attention-deficit/hyperactivity disorder (ADHD) during the completion of VS-WM, self-control, and control tasks. Results indicated that boys with ADHD, relative to typically developing boys, exhibited greater motor activity across tasks, and both groups' activity was greater during EF tasks relative to control tasks. Lastly, VS-WM performance, relative to self-control performance, accounted for significantly more variance in activity across both VS-WM and self-control tasks. Collectively, findings suggest that ADHD-related hyperactivity is positively related to increased cognitive demands and appears to be better explained by deficient VS-WM rather than insufficient self-control.

The effects of physical activity on impulsive choice: Influence of sensitivity to reinforcement amount and delay

Impulsive choice is a diagnostic feature and/or complicating factor for several psychological disorders and may be examined in the laboratory using delay-discounting procedures. Recent investigators have proposed using quantitative measures of analysis to examine the behavioral processes contributing to impulsive choice. The purpose of this study was to examine the effects of physical activity (i.e., wheel running) on impulsive choice in a single-response, discrete-trial procedure using two quantitative methods of analysis. To this end, rats were assigned to physical activity or sedentary groups and trained to respond in a delay-discounting procedure. In this procedure, one lever always produced one food pellet immediately, whereas a second lever produced three food pellets after a 0, 10, 20, 40, or 80-s delay. Estimates of sensitivity to reinforcement amount and sensitivity to reinforcement delay were determined using (1) a simple linear analysis and (2) an analysis of logarithmically transformed response ratios. Both analyses revealed that physical activity decreased sensitivity to reinforcement amount and sensitivity to reinforcement delay. These findings indicate that (1) physical activity has significant but functionally opposing effects on the behavioral processes that contribute to impulsive choice and (2) both quantitative methods of analysis are appropriate for use in single-response, discrete-trial procedures.

Commentary: Transdiagnostic neuroscience of child and adolescent mental disorders--differentiating decision-making in attention-deficit/hyperactivity disorder, conduct disorder, depression and anxiety. A commentary on Sonuga-Barke et al. (2016)

Sonuga-Barke, Cortese, Fairchild, and Stringaris offer us new insights not only on the neuropsychological processes and neurobiological mechanisms involved in the decision-making process but also how some of the most relevant child mental disorders might impact this process through a very comprehensive review of the pertinent literature. Although it is difficult to select specific points for discussing in a so dense review, I would like to highlight some aspects for 'whetting readers appetite' and seduce them to be in contact with the fascinating neurobiology behind an essential aspect of our lives.

Context influences decision-making in boys with attention-deficit/hyperactivity disorder: A comparison of traditional and novel choice-impulsivity paradigms

Attention-deficit/hyperactivity disorder (ADHD) is characterized by an impaired ability to maintain attention and/or hyperactivity/impulsivity. Impulsivity is frequently defined as the preference for small, immediate rewards over larger, delayed rewards, and has been associated with a variety of negative outcomes such as risky behavior and academic difficulty. Extant studies have uniformly utilized the traditional paradigm of presenting two response choices, which limits the generalization of findings to scenarios in which children/adolescents are faced with dichotomous decisions. The current study is the first to examine the effect of manipulating the number of available response options on impulsive decision-making in boys with and without ADHD. A total of 39 boys (ADHD = 16, typically developing [TD] = 23) aged 8-12 years completed a traditional two-choice impulsivity task and a novel five-choice impulsivity task to examine the effect of manipulating the number of choice responses (two vs five) on impulsive decision-making. A five-choice task was utilized as it presents a more continuous array of choice options when compared to the typical two-choice task, and is comparable given its methodological similarity to the two-choice task. Results suggested that boys with ADHD were significantly more impulsive than TD boys during the two-choice task, but not during the five-choice task. Collectively, these findings suggest that ADHD-related impulsivity is not ubiquitous, but rather dependent on variation in demands and/or context. Further, these findings highlight the importance of examining ADHD-related decision-making within the context of alternative paradigms, as the exclusive utilization of two-choice tasks may promote inaccurate conceptualizations of the disorder.