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Background: Prominent theoretical accounts of attention‐deficit/hyperactivity‐disorder (ADHD) hypothesize that reinforcement learning deficits underlie symptoms of ADHD. The Dynamic Developmental Theory and the Dopamine Transfer Deficit hypothesis assume impairments in both the acquisition and extinction of behavior, especially when learning occurs under partial (non‐continuous) reinforcement, and subsequently the Partial Reinforcement Extinction Effect (PREE). Few studies have evaluated instrumental learning in ADHD and the results are inconsistent. The current study investigates instrumental learning under partial and continuous reinforcement schedules and subsequent behavioral persistence when reinforcement is withheld (extinction) in children with and without ADHD. Methods: Large well‐defined samples of children with ADHD (n = 93) and typically developing (TD) children (n = 73) completed a simple instrumental learning task. The children completed acquisition under continuous (100%) or partial (20%) reinforcement, followed by a 4‐min extinction phase. Two‐way (diagnosis by condition) ANOVAs evaluated responses needed to reach the learning criterion during acquisition, and target and total responses during extinction. Results: Children with ADHD required more trials to reach criterion compared to TD children under both continuous and partial reinforcement. After partial reinforcement, children with ADHD executed fewer target responses during extinction than TD children. Children with ADHD executed more responses than TD children during extinction, irrespective of learning condition. Conclusions: The findings demonstrate general difficulties in instrumental learning in ADHD, that is, slower learning irrespective of reinforcement schedule. They also show faster extinction following learning under partial reinforcement in those with ADHD, that is, a diminished PREE. Children with ADHD executed more responses during extinction. Results are theoretically important, with clinical implications for understanding and managing learning difficulties in those with ADHD, as they suggest poorer reinforcement learning and lower behavioral persistence. [ABSTRACT FROM AUTHOR]

Introduction: Attention-Deficit/Hyperactivity Disorder (ADHD) is a debilitating condition affecting children and their families worldwide. Behavioral parent training is a recommended form of empirically supported non-pharmacological intervention for young children with mild to moderate ADHD. However, access to such treatment is limited in many countries. Here we identify the treatment needs of Brazilian families with children demonstrating symptoms of ADHD, and the barriers families face in accessing behavioral treatment. Methods: A qualitative needs assessment was undertaken with parents (n = 23), educators (n = 15), and healthcare providers (n = 16). Semi-structured telephone interviews were conducted, and common themes were identified through inductive coding of participants' responses. Results: Participants reported a lack of accessible behavioral treatment, and delays in accessing treatment when available. The majority of parents had not received behavioral parent training, despite it being a recommended form of treatment. Parents, educators and healthcare providers strongly endorsed a need for practical tools to manage the behavior of children with ADHD. Conclusion: Existing services might not meet the needs of children with ADHD and their families in Brazil. Easily accessed behavioral parent training programs are recommended to address the identified treatment gap for Brazilian children with ADHD and their families. [ABSTRACT FROM AUTHOR]

Altered motivational processing is purported to contribute to ADHD symptoms. A stronger preference for immediate over delayed reward is well documented in ADHD. However, little attention has been paid to children's capacity to withhold responding until a "better" reward becomes available, and their actions while waiting. Using a novel computer task, we examine the ability of children with and without ADHD to wait to collect a large reward in the presence of a small available reward. The effects of a reward-predicting cue on response times and response choices are also explored. Data from 136 children (6–12 years), 90 with ADHD and 46 typically developing (TD) children, are included. The children could collect a small immediately available reward or wait to access a larger reward after a variable delay, its imminent availability sometimes signaled by a cue. Subsequent probe trials explored the effects of longer waiting times and disruption of the cue-reward association. As expected, children with ADHD collected the small immediately available reward more often than TD children. Importantly, they were more likely to terminate waiting once commenced, collecting the small reward or attempting to collect the large reward early. The cue decreased their response time but disrupted their waiting when it no longer consistently predicted reward. Children with ADHD were more likely to abandon efforts to wait, especially when wait times were extended and when expected rewards failed to appear. Behavioral interventions for ADHD should take into account reduced waiting capacity that extends beyond children's preference for immediate reward. [ABSTRACT FROM AUTHOR]

This systematic review synthesizes the empirical literature examining pragmatic language in children diagnosed with attention-deficit/hyperactivity disorder (ADHD). Using a taxonomy of pragmatic language, we compared the pragmatic language profiles of children with ADHD to those of typically developing (TD) children and children with autism. Three databases were searched up to October 2019: PsychInfo; PubMed; and CSA Linguistics and Language Behavior Abstracts. We included 34 studies reporting on 2,845 children (ADHD = 1,407; TD = 1,058; autism = 380). Quality and risk of bias assessments included sample size and representativeness; measure reliability and validity; and missing data management. Children with ADHD were found to have higher rates of pragmatic difficulties than their TD peers. Specific difficulties were identified with inappropriate initiation, presupposition, social discourse, and narrative coherence. Children with ADHD appear to differ from those with autism in the degree of their pragmatic language impairments. General language skills contribute to, but do not explain, pragmatic difficulties in samples of children with ADHD. Though the extant evidence is limited, a preliminary profile of the pragmatic language impairments in children with ADHD is indicated. This supports a call for evidence-based interventions that include pragmatic language skills training. [ABSTRACT FROM AUTHOR]

Understanding the desires and motivations of children with ADHD is important in helping them thrive. Their inner worlds, however, have not been well captured. The Three Wishes task provides minimal cues and structure to elicit their desires and hopes in an unbiased manner. The wishes of 299 school-aged children with ADHD (193 boys, aged 6–12) were elicited during a research diagnostic assessment. We developed a coding scheme to characterize different aspects of their wishes, including beneficiary, valence, and immediacy. Maslow's hierarchy of needs, adapted to take account of the participants' ages, was used to identify the motivations underlying the children's wishes. As expected, many of the wishes reported were for immediate fulfillment, with many reflecting material desires. Affiliative wishes, highlighting the children's desire for positive interpersonal relationships, were also common. There was some evidence for self-actualization/self-betterment goals and a small number of altruistic wishes. A word cloud presents the content of the children's wishes grouped according to this hierarchy. This study highlights the diversity and typicality of the self-reported needs, desires and hopes of children with ADHD. It also serves as a timely reminder of the value of seeking such information directly from children themselves. [ABSTRACT FROM AUTHOR]

Objective: To identify common and shared predictors of academic achievement across samples of children with ADHD. Method: Two clinically referred samples from New Zealand (1 n = 88, 82% boys; 2 n = 121, 79% boys) and two community samples from the United States (3 n = 111, 65% boys; 4 n = 114, 69% boys), completed similar diagnostic, cognitive and academic assessments. Hierarchical multiple regression analyses identified significant predictors of word reading, spelling, and math computation performance in each sample. Results: Entered after IQ, semantic language, age at testing, and verbal working memory emerged as consistent predictors of achievement across academic subjects and samples. Visual-spatial working memory contributed to variance in math performance only. Symptom severity explained limited variance. Conclusions: We recommend evaluations of children with ADHD incorporate assessments of working memory and language skills. Classroom/academic interventions should accommodate reduced working memory and address any identified language weaknesses. [ABSTRACT FROM AUTHOR]

Social interaction difficulties are amongst the most prevalent and pervasive adverse outcomes for children and adolescents with ADHD. Problem-solving strategies are impaired in affected individuals, according to the literature. This study aimed to investigate the social problem-solving skills of children and adolescents with and without ADHD, using objective quantitative measures provided by the Interpersonal Negotiation Strategies Interview (INSI). Since verbal communication skills and working memory may be impaired in ADHD, we investigated their contribution to the performance. Forty-three children and adolescents with ADHD and 27 clinical controls with clinical diagnoses other than ADHD completed the INSI along with measures of verbal communication skills (Verbal Comprehension Index [VCI]): Similarities, Vocabulary and Comprehension subtests from the Wechsler Battery, visual (Corsi Blocks) and verbal (Digit Span) working memory tasks. Groups performed similarly on measures of intellectual functioning, working memory, and verbal communication. For the entire sample, VCI scores were positively correlated with INSI performance scores. The ADHD group performed worse on the INSI than the clinical control group. Linear regression analysis showed that inattention and hyperactivity/impulsivity levels and Similarities predicted INSI's performance. Our findings indicate that interpersonal negotiation difficulties in ADHD are related to DSM-5 defining symptoms of the disorder. [ABSTRACT FROM AUTHOR]

When children with ADHD are presented with behavioral choices, they struggle more than Typically Developing [TD] children to take into account contextual information necessary for making adaptive choices. The challenge presented by this type of behavioral decision making can be operationalized as a Conditional Discrimination Learning [CDL] task. We previously showed that CDL is impaired in children with ADHD. The present study explores whether this impairment can be remediated by increasing reward for correct responding or by reinforcing correct conditional choice behavior with situationally specific outcomes (Differential Outcomes). An arbitrary Delayed Matching-To-Sample [aDMTS] procedure was used, in which children had to learn to select the correct response given the sample stimulus presented (CDL). We compared children with ADHD (N = 45) and TD children (N = 49) on a baseline aDMTS task and sequentially adapted the aDMTS task so that correct choice behavior was rewarded with a more potent reinforcer (reward manipulation) or with sample-specific (and hence response-specific) reinforcers (Differential Outcomes manipulation). At baseline, children with ADHD performed significantly worse than TD children. Both manipulations (reward optimization and Differential Outcomes) improved performance in the ADHD group, resulting in a similar level of performance to the TD group. Increasing the reward value or the response-specificity of reinforcement enhances Conditional Discrimination Learning in children with ADHD. These behavioral techniques may be effective in promoting the learning of adaptive behavioral choices in children with ADHD. [ABSTRACT FROM AUTHOR]

Attention deficit hyperactivity disorder [ADHD] is one of the most common psychiatric disorders of childhood with poor prognosis if not treated effectively. Recommended psychosocial evidence-based treatment for preschool and school-aged children is behavioral parent and teacher training [BPT]. The core elements of BPT are instrumental learning principles, i.e., reinforcement of adaptive and the ignoring or punishment of non-adaptive behaviors together with stimulus control techniques. BPT is moderately effective in reducing oppositional behavior and improving parenting practices; however, it does not reduce blinded ratings of ADHD symptoms. Also after training effects dissipate. This practitioner review proposes steps that can be taken to improve BPT outcomes for ADHD, based on purported causal processes underlying ADHD. The focus is on altered motivational processes (reward and punishment sensitivity), as they closely link to the instrumental processes used in BPT. Following a critical analysis of current behavioral treatments for ADHD, we selectively review motivational reinforcement-based theories of ADHD, including the empirical evidence for the behavioral predictions arising from these theories. This includes consideration of children's emotional reactions to expected and unexpected outcomes. Next we translate this evidence into potential ADHD-specific adjustments designed to enhance the immediate and long-term effectiveness of BPT programs in addressing the needs of children with ADHD. This includes the use of remediation strategies for proposed deficits in learning not commonly used in BPT programs and cautions regarding the use of punishment. Finally, we address how these recommendations can be effectively transferred to clinical practice. [ABSTRACT FROM AUTHOR]

Attention deficit hyperactivity disorder （ADHD） is a neurodevelopmental disorder characterized by elevated and developmentally inconsistent levels of inattention, overactivity and impulsivity that impair daily functioning. It is typically diagnosed in early to middle childhood with an estimated prevalence of 2.2％ to 7.2％, one of the most common psychiatric disorders of this developmental period. While some children with ADHD show symptom remission over time, many continue to meet diagnostic criteria for the disorder in adulthood. The disorder has profound adverse effects on the educational and social development of those affected and places significant burden on their families and communities. Despite extensive research, the precise etiology of ADHD remains uncertain, however, several researchers have proposed that altered motivational processing contributes to the disorderʼs symptoms. These hypotheses emphasize sensitivity to positive reinforcement, and this is reflected in the research literature. The sensitivity of children with ADHD to punishment has received relatively limited theoretical and experimental attention. Here we review the empirical evidence that children with ADHD differ in the way they respond to both positive reinforcement and punishment compared with typically developing children. This includes our own research with New Zealand, American and Japanese children meeting criteria for ADHD. This is followed by clinical recommendations for the use of reward and punishment with children with ADHD. In making these recommendations we highlight the existing gap between research on motivational processes in ADHD and currently available parent management training programs – which do not accommodate altered responsiveness to reward and punishment in children with ADHD. [ABSTRACT FROM AUTHOR]

Reinforcement deficits in ADHD may affect basic operant learning processes relevant for Behavioral Treatment. Behavior acquired under partial reinforcement extinguishes less readily after the discontinuation of reinforcement than behavior acquired under continuous reinforcement, a phenomenon known as the Partial Reinforcement Extinction Effect [PREE], which has great relevance for the emergence of behavioral persistence. The present study examined acquisition and extinction of operant responding under partial and continuous reinforcement in children with and without ADHD. In addition, we evaluated the effectiveness of gradual stretching the reinforcement rate during acquisition for remedying potential acquisition or extinction deficits under partial reinforcement in ADHD. In an operant learning task designed to mimic the task confronted by an animal in a Skinner box, 62 typically developing and 49 children with ADHD (age: 8-12) were presented with a continuous, partial or gradually stretching reinforcement scheme followed by extinction. Both groups of children acquired the instrumental response more slowly and exhibited more behavioral persistence (reduced extinction) when responding was initially reinforced under partial relative to continuous reinforcement, with no differences between groups. Progressive ratio stretching resulted in faster acquisition than partial reinforcement yet promoted equal behavioral persistence, again without differences between ADHD and TD groups. Unlike suggested by previous research, children with ADHD exhibit neither an acquisition deficit under partial reinforcement nor a deficit in PREE. Of relevance for Behavioral Treatment, gradual reinforcement stretching can be used to facilitate response acquisition over purely partial reinforcement while maintaining equal behavioral persistence upon reward discontinuation. [ABSTRACT FROM AUTHOR]

Background: Most research on motivational processes in attention deficit hyperactivity disorder (ADHD) has been undertaken in Western Europe and North America. The extent to which these findings apply to other cultural groups is unclear. The current study evaluated the behavioral sensitivity of Japanese children with and without ADHD to changing reward availability. Forty-one school-aged children, 19 diagnosed with DSM-IV ADHD, completed a signaldetection task in which correct discriminations between two stimuli were associated with different reinforcement frequencies. The response alternative associated with the higher rate of reinforcement switched twice during the task without warning. Findings: Both groups of children developed an initial bias toward the more frequently reinforced response alternative. When the reward contingencies switched the response allocation (bias) of the control group children followed suit. The response bias scores of the children with ADHD did not, suggesting impaired tracking of reward availability over time. Conclusions: Japanese children with ADHD adjust their behavioral responses to changing reinforcer availability less than their typically developing peers. This is not explained by poor attention to task or a lack of sensitivity to reward. The current results are consistent with altered sensitivity to changing reward contingencies identified in non-Japanese samples of children with ADHD. Irrespective of their country of origin, children with ADHD will likely benefit from behavioral expectations and reinforcement contingencies being made explicit together with high rates of reinforcement for appropriate behaviors. [ABSTRACT FROM AUTHOR]

The New Forest Parenting Programme (NFPP) is a parenting program developed for parents who have a child with attention-deficit hyperactivity disorder (ADHD). It is a manualized program that is delivered in a parent's home over 8 weeks, or in a group format, or through a self-help manual. Three randomized controlled trials have been carried out in the United Kingdom. The NFPP group has adapted the program according to feedback from parents and therapists, and for use with different populations, both within the United Kingdom and internationally. The first international trial took place in New York, United States. Trials in Denmark, Hong Kong, and Japan followed. More recently, a trial of the self-help manual has been carried out in mainland China. This paper will outline the adaptions that were needed in order to be able to deliver the program in different countries with their own expectations of parenting, culture, and language. Training had to be differently focused; manuals and handouts had to be revised, translated and back-translated; and supervision had to be delivered at a distance to maintain the fidelity of the program. The international group will outline their experience of running trials in their own countries with the NFPP in a face-to-face format (Denmark), a group format (Hong Kong and Japan), and a self-help format (mainland China). [ABSTRACT FROM AUTHOR]

Background The behavioral sensitivity of children with ADHD to punishment has received limited theoretical and experimental attention. This study evaluated the effects of punishment on the response allocation of children with ADHD and typically developing children. Method Two hundred and ten children, 145 diagnosed with ADHD, completed an operant task in which they chose between playing two simultaneously available games. Reward was arranged symmetrically across the games under concurrent variable interval schedules. Asymmetric punishment schedules were superimposed; responses on one game were punished four times as often as responses on the other. Results Both groups allocated more of their responses to the less frequently punished alternative. Response bias increased significantly in the ADHD group during later trials, resulting in missed reward trials and reduced earnings. Conclusions Punishment exerted greater control over the response allocation of children with ADHD with increased time on task. Children with ADHD appear more sensitive to the cumulative effects of punishment than typically developing children. [ABSTRACT FROM AUTHOR]

Background: Altered sensitivity to positive reinforcement has been hypothesized to contribute to the symptoms of attention-deficit hyperactivity disorder (ADHD). In this study, we evaluated the ability of children with and without ADHD to adapt their behavior to changing reinforcer availability. Method: Of one hundred sixty-seven children, 97 diagnosed with ADHD completed a signal-detection task in which correct discriminations between two stimuli were associated with different frequencies of reinforcement. The response alternative associated with the higher rate of reinforcement switched twice during the task without warning. For a subset of participants, this was followed by trials for which no reinforcement was delivered, irrespective of performance. Results: Children in both groups developed an initial bias toward the more frequently reinforced response alternative. When the response alternative associated with the higher rate of reinforcement switched, the children's response allocation (bias) followed suit, but this effect was significantly smaller for children with ADHD. When reinforcement was discontinued, only children in the control group modified their response pattern. Conclusions: Children with ADHD adjust their behavioral responses to changing reinforcer availability less than typically developing children, when reinforcement is intermittent and the association between an action and its consequences is uncertain. This may explain the difficulty children with ADHD have adapting their behavior to new situations, with different reinforcement contingencies, in daily life. [ABSTRACT FROM AUTHOR]

Altered reward processing has been proposed to contribute to the symptoms of attention deficit hyperactivity disorder (ADHD). The neurobiological mechanism underlying this alteration remains unclear. We hypothesize that the transfer of dopamine release from reward to reward-predicting cues, as normally observed in animal studies, may be deficient in ADHD. Functional magnetic resonance imaging (fMRI) was used to investigate striatal responses to reward-predicting cues and reward delivery in a classical conditioning paradigm. Data from 14 high-functioning and stimulant-naïve young adults with elevated lifetime symptoms of ADHD (8 males, 6 females) and 15 well-matched controls (8 males, 7 females) were included in the analyses. During reward anticipation, increased blood-oxygen-level-dependent (BOLD) responses in the right ventral and left dorsal striatum were observed in controls, but not in the ADHD group. The opposite pattern was observed in response to reward delivery; the ADHD group demonstrated significantly greater BOLD responses in the ventral striatum bilaterally and the left dorsal striatum relative to controls. In the ADHD group, the number of current hyperactivity/impulsivity symptoms was inversely related to ventral striatal responses during reward anticipation and positively associated with responses to reward. The BOLD response patterns observed in the striatum are consistent with impaired predictive dopamine signaling in ADHD, which may explain altered reward-contingent behaviors and symptoms of ADHD. [ABSTRACT FROM AUTHOR]

The present study compared the current intellectual and neuropsychological functioning of 55 children diagnosed with attention deficit hyperactivity disorder ( ADHD group) 4 years earlier with that of an age- and sex-matched control sample. The children in the ADHD group performed less well than the control group on measures of intellectual function, design fluency, spatial organization, and visual memory. Those children who continued to meet DSM-IV criteria for ADHD (persistent ADHD, n = 32) evidenced greater impairment than those showing some symptom remission ( ADHD in partial remission, n = 23). These data confirm the presence of neuropsychological deficits in late childhood/early adolescence among those previously diagnosed with ADHD. The data also suggest that greater cognitive impairment is a feature of persistent ADHD. [ABSTRACT FROM AUTHOR]

Attention-deficit/hyperactivity disorder (ADHD) is characterized by symptoms of inattention and hyperactivity/impulsivity that often persist in adulthood. There is a growing consensus that ADHD is associated with abnormal function of diffuse brain networks, but such alterations remain poorly characterized. Using resting-state functional magnetic resonance imaging, we characterized multivariate (complex network measures), bivariate (network-based statistic), and univariate (regional homogeneity) properties of brain networks in a non-clinical, drug-naive sample of high-functioning young men and women with ADHD (nine males, seven females) and a group of matched healthy controls. Data from our sample allowed the isolation of intrinsic functional connectivity alterations specific to ADHD diagnosis and symptoms that are not related to developmental delays, general cognitive dysfunction, or history of medication use. Multivariate results suggested that frontal, temporal, and occipital cortices were abnormally connected locally as well as with the rest of the brain in individuals with ADHD. Results from the network-based statistic support and extend multivariate results by isolating two brain networks comprising regions between which inter-regional connectivity was significantly altered in the ADHD group; namely, a frontal amygdala-occipital network and a frontal temporal-occipital network. Brain behavior correlations further highlighted the key role of altered orbitofrontal-temporal and frontal-amygdala connectivity for symptoms of inattention and hyperactivity/impulsivity. All univariate properties were similar between groups. Taken together, results from this study show that the diagnosis and the two main symptom dimensions of ADHD are related to altered intrinsic connectivity in orbitofrontal-temporal-occipital and fronto-amygdala-occipital networks. Accord-ingly, our findings highlight the importance of extending the conceptualization of ADHD beyond segregated fronto-striatal alterations. [ABSTRACT FROM AUTHOR]

We review strategies for developing animal models for examining and selecting compounds with potential therapeutic benefit in attention-deficit hyperactivity disorder (ADHD). ADHD is a behavioural disorder of unknown aetiology and pathophysiology. Current understanding suggests that genetic factors play an important role in the aetiology of ADHD. The involvement of dopaminergic and noradrenergic systems in the pathophysiology of ADHD is probable. We review the clinical features of ADHD including inattention, hyperactivity and impulsivity and how these are operationalized for laboratory study. Measures of temporal discounting (but not premature responding) appear to predict known drug effects well (treatment validity). Open-field measures of overactivity commonly used do not have treatment validity in human populations. A number of animal models have been proposed that simulate the symptoms of ADHD. The most commonly used are the spontaneously hypertensive rat (SHR) and the 6-hydroxydopamine-lesioned (6-OHDA) animals. To date, however, the SHR lacks treatment validity, and the effects of drugs on symptoms of impulsivity and inattention have not been studied extensively in 6-OHDA-lesioned animals. At the present stage of development, there are no in vivo models of proven effectiveness for examining and selecting compounds with potential therapeutic benefit in ADHD. However, temporal discounting is an emerging theme in theories of ADHD, and there is good evidence of increased value of delayed reward following treatment with stimulant drugs. Therefore, operant behaviour paradigms that measure the effects of drugs in situations of delayed reinforcement, whether in normal rats or selected models, show promise for the future. LINKED ARTICLES This article is part of a themed issue on Translational Neuropharmacology. To view the other articles in this issue visit [ABSTRACT FROM AUTHOR]

Abstract: ADHD is associated with altered reinforcement sensitivity, despite a number of inconsistent findings. This review focuses on the overlap and differences between seven neurobiologically valid models and lists 15 predictions assessing reinforcement sensitivity in ADHD. When comparing the models it becomes clear that there are great differences in the level of explanation. For example, some models try to explain a single core deficit in terms lower-level reinforcement systems, such as the dopamine transfer to reward back in time. Other models explain multiple deficits, by describing higher-level systems, such as impaired bottom-up prefrontal activation. When reviewing the available experimental evidence in support of the predictions, most experimental studies have been focusing on behavioral changes in the face of reward and response cost over no-reward, and on delay discounting. There is currently a lack in studies that focus on explaining underlying cognitive or neural mechanisms of altered reinforcement sensitivity in ADHD. Additionally, there is a lack in studies that try to understand what subgroup of children with ADHD shows alterations in reinforcement sensitivity. The scarcity in studies testing the neurobiological predictions is explained partly by a lack in knowledge how to test some of these predictions in humans. Nevertheless, we believe that these predictions can serve as a useful guide to the systematic evaluation of altered reinforcement sensitivity in ADHD. [Copyright &y& Elsevier]

Abstract: Attention-deficit hyperactivity disorder (ADHD) is a prevalent and debilitating disorder diagnosed on the basis of persistent and developmentally-inappropriate levels of overactivity, inattention and impulsivity. The etiology and pathophysiology of ADHD is incompletely understood. There is evidence of a genetic basis for ADHD but it is likely to involve many genes of small individual effect. Differences in the dimensions of the frontal lobes, caudate nucleus, and cerebellar vermis have been demonstrated. Neuropsychological testing has revealed a number of well documented differences between children with and without ADHD. These occur in two main domains: executive function and motivation although neither of these is specific to ADHD. In view of the recent advances in the neurobiology of reinforcement, we concentrate in this review on altered reinforcement mechanisms. Among the motivational differences, many pieces of evidence indicate that an altered response to reinforcement may play a central role in the symptoms of ADHD. In particular, sensitivity to delay of reinforcement appears to be a reliable finding. We review neurobiological mechanisms of reinforcement and discuss how these may be altered in ADHD, with particular focus on the neurotransmitter dopamine and its actions at the cellular and systems level. We describe how dopamine cell firing activity is normally associated with reinforcing events, and transfers to earlier time-points in the behavioural sequence as reinforcement becomes more predictable. We discuss how a failure of this transfer may give rise to many symptoms of ADHD, and propose that methylphenidate might act to compensate for the proposed dopamine transfer deficit. [Copyright &y& Elsevier]

Attention-deficit/hyperactivity disorder (ADHD), characterized by hyperactivity, impulsiveness and deficient sustained attention, is one of the most common and persistent behavioral disorders of childhood. ADHD is associated with catecholamine dysfunction. The catecholamines are important for response selection and memory formation, and dopamine in particular is important for reinforcement of successful behavior. The convergence of dopaminergic mesolimbic and glutamatergic corticostriatal synapses upon individual neostriatal neurons provides a favorable substrate for a three-factor synaptic modification rule underlying acquisition of associations between stimuli in a particular context, responses, and reinforcers. The change in associative strength as a function of delay between key stimuli or responses, and reinforcement, is known as the delay of reinforcement gradient. The gradient is altered by vicissitudes of attention, intrusions of irrelevant events, lapses of memory, and fluctuations in dopamine function. Theoretical and experimental analyses of these moderating factors will help to determine just how reinforcement processes are altered in ADHD. Such analyses can only help to improve treatment strategies for ADHD. [ABSTRACT FROM AUTHOR]

This review considers the hypothesis that changes in dopamine signalling might account for altered sensitivity to positive reinforcement in children with ADHD. The existing evidence regarding dopamine cell activity in relation to positive reinforcement is reviewed. We focus on the anticipatory firing of dopamine cells brought about by a transfer of dopamine cell responses to cues that precede reinforcers. It is proposed that in children with ADHD there is diminished anticipatory dopamine cell firing, which we call the dopamine transfer deficit (DTD). The DTD theory leads to specific and testable predictions for human and animal research. The extent to which DTD explains symptoms of ADHD and effects of pharmacological interventions is discussed. We conclude by considering the neural changes underlying the etiology of DTD. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study assessed the effectiveness of a targeted 9-week parent stress management program (PSM) on the parenting stress, mood, family functioning, parenting style, locus of control, and perceived social support of parents of children diagnosed with DSM-IV ADHD. Sixty-three parents from 42 families were randomly assigned to 1 of 2 conditions: immediate treatment or wait-list control. Results of the randomized control trial showed that for mothers, completion of the PSM program was accompanied by significant reductions in parent-domain parenting stress together with significant improvements in parenting style (verbosity, laxness, overreactivity). For fathers, completion of the program was associated with a reduction in verbosity only. Anonymously completed consumer satisfaction questionnaires demonstrated a high degree of satisfaction with the PSM program. [ABSTRACT FROM AUTHOR]

Objective: To compare the global cognitive functioning and frontal lobe functioning of children with and without DSM-IV combined type Attention Deficit Hyperactivity Disorder (ADHD). Method: Participants were 6 to 10 year old, clinic-referred children diagnosed with combined type ADHD, who were medication naïve; and an age (± 3 months) and sex matched group of children without behaviour problems. The performance of the two groups were compared on measures of intellectual functioning and tests designed to assess the functions of the frontal lobes (verbal and-non-verbal fluency, reasoning, problem solving, spatial working memory, attention). Results: The children with ADHD obtained significantly lower Wechsler Intelligence Scale for Children-third edition IQ scores than controls and performed more poorly across the range of frontal lobe tests. Group differences on these tests were attenuated when IQ scores were included in the analyses as a covariate. Conclusions: Children with combined type ADHD have mild to moderate global cognitive impairment together with some impairment of functions subserved by the frontal lobes. Longitudinal studies are required to determine if the deficit in global cognitive functioning is a primary deficit or secondary to the deficit in frontal lobe functioning. The importance of neuro­psychological assessment and follow-up for children with ADHD is stressed. Study limitations relate to the generalizability of the findings and the absence of a psychiatric control group. [ABSTRACT FROM AUTHOR]

Little research has examined the structure and prevalence of attention-deficit/hyperactivity disorder (ADHD) symptoms in university students, including whether symptom structure conforms to the bidimensional (i.e., inattention and hyperactivity-impulsivity) conceptualization of the Diagnostic and Statistical Manual of Mental Disorders (DSMV-IV; American Psychiatric Association, 1994) and whether self-reported symptoms vary across gender and country. A sample of 1,209 university students from three countries (Italy, New Zealand, and the United States) completed a 24-item self-report measure (the Young Adult Rating Scale) tapping ADHD symptomatology. Factor analyses within the U.S. and New Zealand samples supported a bidimensional symptom structure, whereas weaker support for this conceptualization was provided by the Italian sample. Participants did not vary significantly by gender in symptom report; however, Italian students reported significantly more inattention and hyperactivity-impulsivity symptoms than students from the United States, and students from New Zealand reported more inattention symptoms than students from the United States. The prevalence of self-reported ADHD symptoms beyond DSM-IV thresholds for diagnosis ranged from 0% (Italian women) to 8.1% (New Zealand men). The implications of these results for the use of DSM-IV criteria in identifying university students with ADHD are discussed. [ABSTRACT FROM AUTHOR]

Background: Research on altered motivational processes in ADHD has focused on reward. The sensitivity of children with ADHD to punishment has received limited attention. We evaluated the effects of punishment on the behavioral allocation of children with and without ADHD from the United States, New Zealand, and Japan, applying the generalized matching law. Methods: Participants in two studies (Furukawa et al., 2017, 2019) were 210 English-speaking (145 ADHD) and 93 Japanese-speaking (34 ADHD) children. They completed an operant task in which they chose between playing two simultaneously available games. Rewards became available every 10 seconds on average, arranged equally across the two games. Responses on one game were punished four times as often as responses on the other. The asymmetrical punishment schedules should bias responding to the less punished alternative. Results: Compared with controls, children with ADHD from both samples allocated significantly more responses to the less frequently punished game, suggesting greater behavioral sensitivity to punishment. For these children, the bias toward the less punished alternative increased with time on task. Avoiding the more punished game resulted in missed reward opportunities and reduced earnings. English-speaking controls showed some preference for the less punished game. The behavior of Japanese controls was not significantly influenced by the frequency of punishment, despite slowed response times after punished trials and immediate shifts away from the punished game, indicating awareness of punishment. Conclusion: Punishment exerted greater control over the behavior of children with ADHD, regardless of their cultural background. This may be a common characteristic of the disorder. Avoidance of punishment led to poorer task performance. Caution is required in the use of punishment, especially with children with ADHD. The group difference in punishment sensitivity was more pronounced in the Japanese sample; this may create a negative halo effect for children with ADHD in this culture. [ABSTRACT FROM AUTHOR]

Compares the sensitivity of boys with and without attention deficit hyperactivity disorder (ADHD) to differences in reward frequency. Link between symptoms of ADHD and reward sensitivity; Effects of methylphenide on the reward sensitivity of children with ADHD; Use of signal-detection methodology.

Adaptive behavior requires the adjustment of one's behavioral repertoire to situational demands. The learning of situationally appropriate choice behavior can be operationalized as a task of Conditional Discrimination Learning (CDL). CDL requires the acquisition of hierarchical reinforcement relations, which may pose a particular challenge for children with Attention Deficit Hyperactivity Disorder (ADHD), particularly in light of documented deficits in short-term/working memory and delay aversion in ADHD. Using an arbitrary Delayed Matching-To-Sample task, we investigated whether children with ADHD (N = 46), relative to Typically Developing children (TD, N = 55), show a deficit in CDL under different choice delays (0, 8, and 16 s) and whether these differences are mediated by short-term/working memory capacity and/or delay aversion. Children with ADHD demonstrated poorer CDL than TD children under 8 and 16-second delays. Non-delayed CDL performance did not differ between groups. CDL differences were not mediated by short-term/working memory performance or delay aversion. Moreover, CDL performance under an 8-second delay was a better predictor of clinical status than short-term/working memory performance or delay aversion. CDL, under conditions of delay, is impaired in children with ADHD. This may lead to difficulties discriminating between different situational demands and adapting behavior according to the prevailing reward contingencies or expectations. [ABSTRACT FROM AUTHOR]

The authors respond to comments made by Jonathan Williams about their article on attention deficit hyperactivity disorder (ADHD). Although Williams shared their thoughts about ADHD being highly heterogenous, the authors believed that there is much to be learned from examining the behavioral and clinical implications of simple, definable, neurophysiological changes in dopaminergic function. Their article is aimed at discussing the altered sensitivity to reinforcers that is observed in ADHD.

Objective: Although instrumental learning deficits are, among other deficits, assumed to contribute to attention-deficit/hyperactivity disorder (ADHD), no comprehensive systematic review of instrumental learning deficits in ADHD exists. This review examines differences between ADHD and typically developing (TD) children in basic instrumental learning and the effects of reinforcement form, magnitude, schedule, and complexity, as well as effects of medication, on instrumental learning in children with ADHD.Method: A systematic search of PubMed, PsyINFO, CINAHL, EMBASE+EMBASE CLASSIC, ERIC, and Web of Science was conducted for articles up to March 16, 2020. Experimental studies comparing instrumental learning between groups (ADHD versus TD) or a manipulation of reinforcement/medication within an ADHD sample were included. Quality of studies was assessed with an adapted version of the Hombrados and Waddington criteria to assess risk of bias in (quasi-) experimental studies.Results: A total of 19 studies from among 3,384 non-duplicate screened articles were included. No difference in basic instrumental learning was found between children with ADHD and TD children, nor effects of form or magnitude of reinforcement. Results regarding reinforcement schedule and reversal learning were mixed, but children with ADHD seemed to show deficits in conditional discrimination learning compared to TD children. Methylphenidate improved instrumental learning in children with ADHD. Quality assessment showed poor quality of studies with respect to sample sizes and outcome and missing data reporting.Conclusion: The review identified very few and highly heterogenous studies, with inconsistent findings. No clear deficit was found in instrumental learning under laboratory conditions. Children with ADHD do show deficits in complex forms of learning, that is, conditional discrimination learning. Clearly more research is needed, using more similar task designs and manipulations. [ABSTRACT FROM AUTHOR]

Individual differences in reward-related learning are relevant to many behavioral disorders. Sensory cues that predict reward can become incentive stimuli that adaptively support behavior, or alternatively, cause maladaptive behaviors. The spontaneously hypertensive rat (SHR) expresses a genetically determined elevated sensitivity to delay of reward, and has been extensively studied as a behavioral model for attention deficit hyperactivity disorder (ADHD). We investigated reward-related learning in the SHR, comparing them to Sprague-Dawley (SD) rats as a reference strain. A standard Pavlovian conditioned approach task was used, in which a lever cue was followed by reward. Lever presses could occur while the lever was extended, but had no effect on reward delivery. The behavior of both the SHRs and the SD rats showed that they learnt that the lever cue predicted reward. However, the pattern of behavior differed between the strains. During lever cue presentation, SD rats pressed the lever more often and made fewer magazine entries than SHRs. When lever contacts that did not result in lever presses were analyzed, there was no significant difference between SHRs and SDs. These results suggest that the SHRs attributed less incentive value to the conditioned stimulus than the SD rats. During the presentation of the conditioned cue, cue directed responses are called sign tracking responses, whereas responses directed towards the food magazine are called goal tracking responses. Analysis of behavior using a standard Pavlovian conditioned approach index to quantify sign and goal tracking tendencies showed that both strains had a tendency towards goal tracking in this task. However, the SHRs showed a significantly greater goal tracking tendency than the SD rats. Taken together, these findings suggest that attribution of incentive value to reward predicting cues is attenuated in SHRs, which might explain their elevated sensitivity to delay of reward. [ABSTRACT FROM AUTHOR]

• Hyporesponsiveness to reward-predicting cues in ADHD extends beyond monetary rewards. • Adults with ADHD show decreased striatal activation to affiliative reward cues. • Adults with and without ADHD respond similarly to food reward stimuli. Altered reward sensitivity has been proposed to underlie symptoms of attention deficit hyperactivity disorder (ADHD). Functional magnetic resonance imaging (fMRI) studies have reported hypoactivation to reward-predicting cues in the ventral striatum among individuals with ADHD, using experimental designs with and without behavioral response requirements. These studies have typically used monetary incentives as rewards; however, it is unclear if these findings extend to other reward types. The current study examined striatal responses to anticipation and delivery of both affiliative and food reward images using a classical conditioning paradigm. Data from 20 typically developing young adults, and 20 individuals diagnosed with ADHD were included in a region-of-interest analysis for a priori striatal regions. Consistent with findings from studies using monetary rewards, individuals with ADHD showed decreased activation to cues predicting affiliative rewards in the bilateral ventral and dorsal striatum and increased activation to the delivery of affiliative rewards in the ventral striatum. No group differences were found in striatal responses to food reward cues or images. These results suggest hyposensitivity to reward-predicting cues in ADHD extends to affiliative rewards, with important implications for understanding and managing the learning and social functioning of those with ADHD. [ABSTRACT FROM AUTHOR]

Abstract: An altered response to reinforcement has been proposed as a mechanism underlying many of the symptoms of attention deficit hyperactivity disorder (ADHD). We measured sensitivity to delay of reinforcement in two animal models of ADHD, the spontaneously hypertensive rat (SHR) and a newly proposed model, the genetically hypertensive (GH) rat. A task previously used to measure effects of delay of reinforcement in children with ADHD was adapted for use in the present experiment. The SHR and GH rats were compared to their respective genetic control strains, Wistar-Kyoto (WKY), and Wistar (WI). The experimental task required pressing one of two available levers each trial. One lever delivered an immediate reinforcement, and the other lever a delayed reinforcement. Both the SHR and GH strains allocated significantly more responses to the immediately reinforced lever than their genetic control strains. Individual instances of reinforcement differentially affected response allocation in the GH but not the SHR. These findings support the use of the SHR and GH rat to model altered response to reinforcement, and demonstrate the additional value of the GH strain to model the effects of individual instances of reinforcement in children with ADHD. [Copyright &y& Elsevier]

Attention deficit hyperactivity disorder (ADHD) has been associated with neural hyposensitivity to reward-predicting cues. Methylphenidate is widely used in the management of the disorder's symptoms, but its effects on reward sensitivity in ADHD are unknown. The current study used fMRI to measure striatal responses to reward-predicting cues in adults with ADHD on and off methylphenidate and a control group, during a classical conditioning task. Responses to cued reward were also explored. Larger differences in the ventral striatum activation to reward cues versus non-reward cues were observed when the ADHD participants were on methylphenidate compared to placebo. In response to cued-reward outcome, an exploratory analysis showed methylphenidate reduced the BOLD time-series correlation between the dorsal striatum and dorsal medial prefrontal cortex. Methylphenidate's therapeutic effects may be mediated by altering reward processing in individuals with ADHD. • MPH modulates BOLD responses to reward-predicting cues in ADHD. • MPH enhanced striatal discrimination of reward and non-reward cues in ADHD. • MPH reduced corticostriatal connectivity during cued reward in ADHD. • Therapeutic effects of MPH may involve altered reward processing. [ABSTRACT FROM AUTHOR]