The dual pathway model of AD/HD: an elaboration of neuro-developmental characteristics

Enhancing effects of exercise and neurofeedback: A systematic review and meta-analysis of computer game-based interventions for pediatric ADHD

OBJECTIVE

While numerous reviews examine digital interventions, including computer game-based, evidence regarding their effectiveness for ADHD symptoms remains mixed. Focusing on computer game-based interventions, this study aims to identify specific intervention features and trial-related factors that influence outcomes in pediatric ADHD symptoms through a systematic review and meta-analysis of randomized controlled trials.

METHODS

Comprehensive literature searches were conducted in Web of Science, PubMed and PsycINFO. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Seventeen studies were included. Beyond common game characteristics, some interventions incorporated additional elements-such as neurofeedback, physical exercise via virtual reality (VR) and social components-allowing subgroup analyses. The neurofeedback subgroup showed the largest effect size (standardized mean difference (SMD)=-0.51, 95 % confidence interval (CI) [-0.88, -0.15], heterogeneity index (I2)=45.85 %, p < 0.05, very low certainty of evidence), followed by the physical exercise/VR subgroup (SMD=-0.40, 95 %CI [-0.76, -0.04], I2=0.00 %, p < 0.05, very low certainty of evidence). Other subgroups, including those with social components or without additional elements, did not show significant effect sizes. The physical exercise/VR subgroup demonstrated small-to-medium effect sizes in both inattention and hyperactivity/impulsivity subscales, whereas the neurofeedback subgroup showed similar effects only in inattention. Trial-level factors, including participant demographics and intervention duration, showed no significant relationship with SMD in meta-regression.

CONCLUSION

Although inconclusive, synergizing with game dynamics, neurofeedback and physical exercise/VR may enhance effectiveness of computer game-based interventions in addressing pediatric ADHD symptoms. Particularly, interventions with physical exercise/VR have potential to address both inattention and hyperactivity/impulsivity.

Association between ADHD symptoms, physical effort discounting, and unhealthy lifestyles in adults

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition marked by difficulties with attention, increased activity levels, and impulsive behaviour, which can impact social, academic, and work-related performance. Its presence in adults is often overlooked and inadequately addressed. Emerging research suggests a link between ADHD and unhealthy lifestyles, including sedentary behaviour, substance use, and effort discounting, a decision-making process where individuals undervalue rewards requiring significant physical or cognitive effort. This study investigates the association between ADHD symptoms, physical effort discounting, and indicators of unhealthy lifestyles in young adults. We recruited 181 participants aged 18-33 years. They completed the Effort-Expenditure for Rewards Task (EEfRT) and a hypothetical effort-discounting task, alongside questionnaires assessing ADHD and developmental co-ordination disorder (DCD) symptoms, physical activity, alcohol, tobacco and drug use. A logistic mixed model was used to analyze effort-discounting decisions, while regression analyses assessed the influence of ADHD symptoms and effort discounting on unhealthy lifestyle indicators. EEfRT decisions were significantly influenced by reward probability, monetary value, and ADHD medication status, whereas choices in the hypothetical effort-discounting task were influenced by money, effort and ADHD symptoms. When exploring the association between all variables, ADHD symptoms were positively correlated with effort discounting in the hypothetical task, smoking, and DCD. Effort discounting was associated with a sedentary lifestyle while smoking correlated with higher BMI and alcohol consumption. Linear and logistic regressions suggested that ADHD symptoms and effort discounting were associated with a sedentary lifestyle, and smoking status was significantly explained by ADHD symptoms. These findings highlight the need for targeted interventions addressing both ADHD symptomatology and lifestyle factors to improve outcomes in affected individuals.

Contingency-based flexibility mechanisms through a reinforcement learning model in adults with attention-deficit/hyperactivity disorder and obsessive-compulsive disorder

BACKGROUND AND AIMS

Impaired cognitive flexibility is associated with the characteristic symptomatology of ADHD and OCD. However, the mechanisms underlying learning and flexibility under uncertainty in adults with OCD or ADHD remain unclear. This study aimed to identify the mechanisms underlying contingency-based flexibility in a sample of adults with ADHD or OCD, using probabilistic learning reversal task, functional near-infrared spectroscopy, and computational modelling.

METHODS

148 Spanish-speaking adults (43 OCD, 53 ADHD and 52 healthy controls) completed a probabilistic learning reversal task. Previously, we obtained a resting-state functional connectivity (rsFC) record between several frontoparietal network regions using functional near-infrared spectroscopy. Contingency-based flexibility was explored by reinforcement learning model in combination with a Bayesian Generalized Logistic Model (GLM). The reinforcement learning parameters included reward and punishment learning rates (feedback sensitivity), and inverse temperature (decision consistency). Bayesian GLM parameters were defined to measure final accuracy, learning and speed of learning.

RESULTS

We found that the groups showed optimal performance in the discrimination block and a higher performance of healthy controls compared to patients in the reversal block. Model parameters predicted task performance differently by phase and group. In the discrimination block, while the performance of healthy controls was predicted by a combination of parameters such as high inverse temperature and punishment learning rate together with low values of reward learning rate, in the case of the clinical groups it was only by high inverse temperature. In the reversal block, the performance of OCD was predicted by high punishment learning rate and that of ADHD by low reward learning rate; in contrast, the performance of healthy controls was also predicted by a combination of parameters with high punishment learning rate and inverse temperature as predictors. We found the rsFC between the left and right posterior parietal cortex appears to credibly predict performance in the discrimination block in healthy controls.

CONCLUSIONS

These results suggest that OCD and ADHD in adults could be associated with poor behavioral adaptation when reinforcement-punishment contingencies changed. The difficulties observed in ADHD and OCD likely stem from different underlying mechanisms that affect both learning and switching processes. Findings highlighted how OCD appears to show greater sensitivity to punishment when there is uncertainty about the behavior-outcome association. Instead, the ADHD group can be guided by sensitivity to reinforcement. Interhemispheric rsFC posterior parietal cortex could be important for optimal learning of the task.

Behavioral and neurofunctional profiles of delay aversion in children with attention-deficit hyperactivity disorder

Despite substantial efforts to unravel cognitive heterogeneity in ADHD, the examination of motivational variability, particularly delay aversion, remains limited. This study aimed to identify homogeneous delay-averse profiles in children with ADHD to understand motivational deficits. Delay-averse profiles were examined in a clinically well-characterized sample of 43 children with ADHD and 47 control participants using cluster analyses on an experiential delay discounting task. External validation analyses included parents' and teachers' clinical ratings, and fNIRS-based resting-state functional connectivity (rsFC) from the frontoparietal (FPN) and the default mode (DMN) networks. A five-profile solution best fit the data. Two clusters, labeled Conventional and Conventional-steeper, exhibited a conventional reward discount with increased delay but differed in the discounting slope. Three clusters demonstrated altered discounting: Steep discounting (abrupt devaluation of the reward), Shallow discounting (shallow discounting), and Zero discounting (no devaluation across delay durations). 77.78% of ADHD-C children clustered into steep discounting profiles, while 41.67% of ADHD-IN children were found in Shallow and Zero profiles, showing a significant disparity in the distribution of categorical presentations. External validation showed no differences in clinical ratings. However, clusters showing Zero and Shallow discounting demonstrated hypoconnectivity within and between FPN and DMN nodes. Delay aversion in ADHD spans a continuum from decreased to increased discounting rather than being solely defined by steeper discounting. These findings highlight the relevance of dimensional approaches in capturing ADHD's motivational heterogeneity and identifying distinct neurobiological substrates, with implications for improving diagnostic protocols and intervention strategies through the incorporation of behavioral measures of reward processing.

ADHD, stress, and anxiety

Recent findings on stress and anxiety in attention deficit hyperactivity disorder (ADHD) suggest that specific processes related to brain developmental disorganization could create a vulnerable background that increases sensitivity to stress stimuli from the psychosocial environment. These basic neurodevelopmental processes are closely related to the developmental mechanisms of primitive functions and their integration or disintegration. In this context, the psychopathological processes that manifest in ADHD are linked to the mechanisms of disturbed inhibitory functions that may cause incongruent neural interactions ("neural interference") between the more primitive functions and the higher levels of attentional and cognitive neural processes. These disturbed developmental processes may also determine increased sensitivity to stressful experiences that, in ADHD cases, could lead to the manifestations of various psychopathological symptoms such as disturbed attentional and motor functions, anxiety, and depression, among other cognitive and affective disturbances. These findings, based on previous research, suggest novel framework and hypothesis on how this neurodevelopment-based increased sensitivity to stress stimuli could manifest in the etiopathogenesis of ADHD in its relationship with cognitive, affective, and motor deficits.

The Multidimensional Dynamic Feedback Model: A Comprehensive Framework for Understanding and Managing Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder characterized by persistent inattention, hyperactivity, and impulsivity. These symptoms can significantly impact academic performance, social interactions, and daily activities, often creating cycles that worsen long-term challenges. This review introduces the Multidimensional Dynamic Feedback Model (MDFM), which aids in understanding ADHD's development and guiding intervention strategies. The model emphasizes the dynamic interactions among genetic, environmental, cognitive, and behavioral factors. The MDFM consists of three key aspects: (1) the interplay between genetic and environmental factors in shaping ADHD's biological basis, (2) the role of cognitive and neural processes in driving core symptoms, and (3) the influence of behavioral feedback loops that reinforce negative behaviors and hinder adaptation. The model highlights the importance of personalized interventions and effective feedback systems, including early prevention, supportive family and school environments, and the impact of social and cultural backgrounds on treatment outcomes. As a comprehensive framework, the MDFM offers a holistic perspective for clinicians, aiming to enhance long-term outcomes and promote the health and well-being of individuals with ADHD across the lifespan. By addressing implementation challenges, the model seeks to improve ADHD prevention and management, ultimately supporting individuals and their communities.

Social cognition in autism and ADHD

Social cognition is a crucial capacity for social functioning. The last decades have seen a plethora of social cognition research in neurodevelopmental conditions, foremost autism and, to a lesser extent, ADHD, both characterized by social challenges. Social cognition is a multifaceted construct comprising various overlapping subdomains, such as Theory of Mind/mentalizing, emotion recognition, and social perception. Mechanisms underpinning social cognition are complex, including implicit and explicit, cognitive and affective, and hyper- and hypo-social information processing. This review explores the intricacies of social cognition in the context of autism and ADHD. Research indicates altered performance on social cognition tests in autism, compared to neurotypical groups, with social cognition alterations having a small but robust effect on the defining features of autism. The nature of such alterations in autism appears primarily in relation to implicit processing. ADHD groups show intermediate social cognition performance, appearing to be influenced by executive function difficulties. Social cognition varies with intellectual and verbal abilities and seems to improve with age in autism and ADHD. Social skills interventions in autism, and stimulant medication in ADHD have been shown to improve social cognition test performance, while mentalizing training effects in autism are less conclusive. A limitation of the field is that social cognition constructs and tests are not well delineated. Further, most research has been embedded in a nativist approach rather than a constructivist approach. The former has been questioned for ignoring environmental contributions, especially the dimension of mutual miscommunication between neurodivergent and neurotypical individuals.

Methylphenidate stabilizes dynamic brain network organization during tasks probing attention and reward processing in stimulant-naïve children with ADHD

Children with ADHD often exhibit fluctuations in attention and heightened reward sensitivity. Psychostimulants, such as methylphenidate (MPH), improve these behaviors in many, but not all, children with ADHD. Given the extent to which psychostimulants are prescribed for children, coupled with variable efficacy on an individual level, a better understanding of the mechanisms through which MPH changes brain function and behavior is necessary. MPH's primary action is on catecholamines, including dopamine and norepinephrine. Catecholaminergic signaling can influence the tradeoff between flexibility and stability of brain function, which is one candidate mechanism through which MPH may alter brain function and behavior. Time-varying functional connectivity, which models how functional brain networks reconfigure on short timescales, can be used to examine brain flexibility versus stability, and is thus well-suited to test how MPH impacts brain function. Here, we scanned stimulant-naïve children with ADHD (8-12 years) on and off a single dose of MPH. In the MRI machine, participants completed two attention-demanding tasks: 1) a standard go/no-go task and 2) a rewarded go/no-go task. For both tasks, using a within-subjects design, we compared the degree to which brain organization changed throughout the course of the MRI scan, termed whole brain flexibility, on and off MPH. We found that whole brain flexibility decreased on MPH. Further, individuals with greater decreases in whole brain flexibility on MPH exhibited greater improvements in task performance. Together, these results provide novel insights into the neurobiological mechanisms underlying the effectiveness of MPH administration for children with ADHD.

"I Found Comfort in Exercising": Exploring Experiences With Exercise for Adults With Attention-Deficit/Hyperactivity Disorder

Little is known about how adults with attention-deficit/hyperactivity disorder (ADHD) experience exercise, resulting in a lack of recommendations for supporting this population. We aimed to explore how adults with ADHD experience exercise as a management tool before and after diagnosis and how and why individuals experience issues related to exercise dependence. Fifteen active adults with a diagnosis of ADHD participated in semistructured interviews. Three overarching themes were identified: (a) exercise as a necessity for ADHD, reflecting the need to exercise before a formal ADHD diagnosis, and use of exercise as a management tool postdiagnosis; (b) goals and achievements to live by, reflecting how exercise patterns revolved around a need to make progress toward targets; and (c) activity or exercise: a roller coaster journey, covering the ups and downs of exercise journeys. This article highlights the importance of exercise for adults to manage ADHD and how this can be encouraged and supported.

Exploring the associations between symptom severity, metacognition, problematic social media use and cyberbullying in treatment naïve adolescents with Attention Deficit and Hyperactivity Disorder

This study investigates the relationship between ADHD symptom severity, metacognition, problematic social media use, and cyberbullying/cybervictimization in treatment-naïve adolescents. Understanding these relationships is vital for enhancing ADHD intervention strategies. Using a cross-sectional design, 97 adolescents meeting DSM-5 criteria for ADHD without any comorbidity and 97 healthy controls were assessed. Measures included the Metacognitions Questionnaire for Children, Social Media Disorder Scale, Revised Cyberbullying Inventory-II, and Revised Conners' Parent Rating Scale-Short. The comparisons were performed with independent samples' t tests and the associations were estimated by using Pearson's bivariate correlations and multiple regression analyses. Results revealed that adolescents with ADHD exhibited higher levels of dysfunctional metacognitions, problematic social media use, cyberbullying, and cybervictimization compared to controls. Regression analysis showed significant positive associations between ADHD symptoms, specific metacognitions (e.g., positive meta-worry, cognitive monitoring), and problematic social media use. This study, the first of its kind among treatment-naïve ADHD adolescents, provides valuable insights into the relationship between ADHD symptoms and particular metacognitions (i.e. positive meta-worry, cognitive monitoring) and problematic social media use. These findings contribute to a deeper understanding of ADHD in adolescence and may inform the development of targeted prevention and treatment strategies, particularly relevant given adolescents' susceptibility to social media's influence and their potential for cognitive flexibility in rehabilitation contexts.

Transcranial direct current stimulation improves time perception in children with ADHD

Individuals with ADHD struggle with time perception. The ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) are two distinct cortical areas that are involved in the psychopathology of ADHD, including time perception. In the present study, we aimed to explore if modulation of the excitability of these areas with non-invasive brain stimulation alters time perception in ADHD. Twenty-six children with ADHD performed time discrimination and time estimation/reproduction tasks in five sessions with one week interval and specific tDCS conditions. The tDCS conditions were anodal left dlPFC/cathodal right vmPFC, the reversed electrode positioning, isolated anodal left dlPFC, right vmPFC stimulation with extracranial return electrodes, and sham stimulation. An improved time discrimination was observed in all real stimulation conditions compared to sham stimulation, however the results did not differ between real stimulation conditions. For the time reproduction/estimation task, anodal vmPFC/cathodal dlPFC, isolated anodal dlPFC stimulation and isolated anodal vmPFC stimulation with extracranial return electrodes improved time reproduction, but not estimation, compared to sham stimulation. These results imply that the left dlPFC and right vmPFC are involved in time estimation, whereas the right vmPFC might be more critical for time reproduction. This finding is discussed in light of task and stimulus properties.

Facial Affect Recognition and Executive Function Abnormalities in ADHD Subjects: An ERP Study

Attention-deficit/hyperactivity disorder (ADHD) affects approximately 12% of children worldwide. With a 50% chance of persistence into adulthood and associations with impairments in various domains, including social and emotional ones, early diagnosis is crucial. The exact neural substrates of ADHD are still unclear. This study aimed to reassess the behavioral and neural metrics of executive functions and neural substrates of facial affect recognition. A total of 117 ADHD patients and 183 healthy controls were evaluated by two Go/NoGo tasks: the classic visual continuous performance test and the emotional continuous performance test, which requires facial affect encoding. Group differences between ADHD subjects and healthy controls were assessed using analysis of covariance (ANCOVA), with age and sex included as covariates. Dependent variables comprised behavioral (number of omission and commission errors, reaction time, and reaction time variability) and neurophysiological measures (event-related potentials [ERPs]). As the main result, we identified significant differences between ADHD patients and healthy controls in all behavioral metrics, one neural marker of action inhibition (P3d) and the facial processing marker (N170). The differences were moderate-to-large when expressed as effect size measures in behavioral variables and small-to-moderate for neurophysiological variables. The small-to-moderate effect sizes obtained from the neurophysiological measures suggest that ERPs are insufficient as sole markers for effectively screening emotion and face processing abnormalities in ADHD.

Exploring the potential of Braingame Brian for executive function improvement in Spanish-speaking children with ADHD: A pilot study

Considering the implications of executive function (EF) in the core symptoms of attention deficit hyperactivity disorder (ADHD), further research is required on strategies such as therapies, treatments, and rehabilitation programs focused on improving EF. This study aimed to assess the potential of an EF training program called "Braingame Brian" in improving working memory, inhibition, and cognitive flexibility in children with ADHD. The programme was developed in the Netherlands and has been shown to be effective in pilot studies of ADHD populations conducted in this country. However, it has not been used before in the Spanish-speaking population. A total of 41 children (aged 8-12 years) were assigned to the EF training or waitlist control groups. The intervention consisted of a 25-session training programme of approximately 45 min per day for nine consecutive weeks. Treatment outcomes were assessed using cognitive tasks of the trained EF, as well as evaluations of EF behaviors by parents and teachers. The initial findings suggest that the implementation of the Braingame Brian programme may be associated with improvements in working memory, inhibition, and cognitive flexibility. These preliminary results also indicate the potential for enhancements in parents' and teachers' perceptions of EF difficulties in children with ADHD.

Incremental Validity of ADHD Dimensions in the Predictions of Emotional Symptoms, Conduct Problems, and Peer Problems in Adolescents Based on Parent, Teacher, and Self-Ratings

Background: The present study investigated the incremental validity of the ADHD dimensions of inattention (IA), hyperactivity (HY), and impulsivity (IM) in the predictions of emotion symptoms (ESs), conduct problems (CPs), and peer problems (PPs) in adolescents based on parent, teacher, and self- ratings. Method: A total of 214 ratings were collected from adolescents, their parents, and teachers in Australia. A structural equation modeling approach was employed to evaluated incremental validity. Results: The findings revealed that, controlling for gender, IM contributed moderate, low, and low levels of variance in predicting ESs based on parent, teacher, and self-ratings, respectively. Additionally, IM contributed moderate, substantial, and moderate levels of variance to CP predictions based on parent, teacher, and self-ratings, respectively. Furthermore, after controlling for gender, IM, and HY, parent-rated IA contributed a low level of variance to the prediction of ESs, while teacher and self-rated IA did not contribute significantly to the prediction of ESs, CPs, or PPs. Conclusions: The findings underscore the differential predictive validity of ADHD dimensions across informants and outcomes, highlighting impulsivity's stronger association with conduct problems and emotional symptoms. These results have theoretical and practical implications for understanding ADHD-related risks in adolescence and tailoring interventions accordingly.

Behavioral and Emotional Responding to Punishment in ADHD: Is Increased Emotionality Related to Altered Behavioral Responding?

Children with ADHD are theorized to experience increased negative emotional responses to punishment, compared to typically developing (TD) children, resulting in altered behavioral responding (Amsel, 1992). However, this has not been empirically tested. The current study evaluated the effects of punishment and reward on the behavioral and emotional responding of children with and without ADHD. Fifty-three children with ADHD (64.15% boys) and 46 TD children (47.83% boys), age 6-12, completed a task in which they chose between playing two simultaneously available games. Reward was arranged symmetrically across the games; responses on one game were punished four times as often as responses on the other game. Children's negative and positive emotional expressions were assessed during task completion with facial expression coding. Results indicated both groups showed a preference for playing the less punished game. Children with ADHD took longer to respond after punishment and reward compared to TD children. Negative emotional expressions increased with time on task for those with ADHD, the opposite pattern was seen in TD children. Children with ADHD showed more positive emotional expressions overall. The effect of ADHD on increased response times after reward was statistically fully mediated by increased positive facial expressions. Findings indicate children with ADHD do not show an altered response bias under punishment compared to TD children, but their cumulative negative emotional responding may indicate problems with building frustration tolerance as hypothesized by Amsel (1992). Results are theoretically important as they suggest increased emotional responding in ADHD is associated with slower responding.

PENDAH program for parents with children with attention deficit hyperactivity disorder. French adaptation of a behavioral parent training group: pilot study

Behavioral parent training (BPT) is recognized as an effective part of the care offered to children with attention deficit hyperactivity disorder (ADHD). The aim of this pilot study was to objectively examine the effect that this intervention may have on motor activity, in addition to the measures classically found in this type of study. Parents of 24 school-aged children (6-12 year) with ADHD who met eligibility criteria were enrolled in the study. Before, after and five months after the intervention, we used three-dimensional accelerometers over one-week periods to measure the children's motor activity, and questionnaires for parental stress, quality of life, ADHD symptoms, anxiety and sensory disorders. To measure motor activity, a control group of normotypic children matched for age, sex and socio-professional category was set up. The experimental group showed slight decreases in motor activity compared with the control group, particularly in the classroom. The intervention showed improvements for parents in average stress and quality of life, and for children in average intensity global ADHD symptom, inattention, opposition and aggression, in line with previous studies on the effectiveness of BPT. The trial is the first clinical study to assess the effects of BPT on motor activity in children with ADHD.

Attention Deficit Hyperactivity Disorder, Cannabis Use, and the Endocannabinoid System: A Scoping Review

There is emerging evidence that the endocannabinoid system (ECS) plays a significant role in the pathophysiology of many psychiatric disorders, including attention deficit hyperactivity disorder (ADHD). Increasing evidence suggests that a number of neurobiological correlates between endogenous cannabinoid function and cognitive dysfunction are seen in ADHD, making the ECS a possible target for therapeutic interventions. Cannabis use and cannabis use disorder are more prevalent in individuals with ADHD, compared to the general population, and there is growing popular perception that cannabis is therapeutic for ADHD. However, the relationship between cannabis use and ADHD symptomology is poorly understood. Further understanding of the role of the ECS in ADHD pathophysiology and the molecular alterations that may be a target for treatment is needed. To further the science on this emerging area of research, this scoping review describes the preclinical and clinical evidence seeking to understand the relationship between the ECS and ADHD.

The apple does not fall far: stable predictive relationships between parents' ratings of their own and their children's self-regulatory abilities

Having control over your own behavior and impulses is a critical skill that influences children's academic, social, and emotional development. This study investigates the stability and predictive relationships between parents' ratings of their own and their children's executive function and delay aversion. Using data from approximately 1700 families collected during the COVID-19 pandemic, we employed hierarchical structural equation models and cross-lagged panel models to analyze the temporal stability and directional influences of executive function and delay aversion assessments.Our analysis revealed a substantial latent correlation (r = 0.48, p < 0.001) between parents' and children's executive function problems, indicating a shared variance of approximately 23%. Significant cross-lagged effects were found, with parental executive functions at T1 predicting child executive functions at T2 (β = 0.16, p = 0.005). For delay aversion, we found a latent correlation of r = 0.53 (p < 0.001) and significant within-timepoint and temporal stability, but no cross-lagged effects.These findings suggest that higher levels of executive function problems reported by parents at T1 correspond to an increased perception of similar problems in their children at T2. This highlights the importance of parental self-perception in assessing children's abilities. Our results highlight the importance of incorporating family dynamics into interventions targeting executive function difficulties and delay aversion in children, and understanding this interplay enables the development of more effective, individualized approaches to support positive developmental outcomes.

Social functioning in children with ADHD: an examination of inhibition, self-control, and working memory as potential mediators

Children with attention-deficit/hyperactivity disorder (ADHD) experience a host of social problems, in addition to significant impairments in behavioral inhibition, working memory, and self-control. Behavioral inhibition and working memory difficulties have been linked with social functioning deficits, but to date, most studies have examined these neurocognitive problems either in isolation or as an aggregate measure in relation to social problems, and none has considered the role of self-control. Thus, it remains unclear whether all of these executive functions are linked with social problems or if the link can be more parsimoniously explained by construct overlap. Fifty-eight children with ADHD and 63 typically developing (TD) children completed tests assessing self-control, behavioral inhibition, and working memory; parents and teachers rated children's social functioning. Examination of potential indirect effects with the bootstrapping procedure indicated that working memory mediated the relation between group membership (ADHD, TD) and child social functioning based on teacher but not parent ratings. Behavioral inhibition and self-control did not have direct relations with either parent- or teacher-rated social functioning. These findings point to important differences regarding how executive functioning difficulties manifest at school compared to home, as well as the specific executive function components that predict ADHD-related social difficulties.

Acute aerobic exercise modulates cognition and cortical excitability in adults with attention-deficit hyperactivity disorder (ADHD) and healthy controls

Evidence suggests aerobic exercise has beneficial effects on cognitive performance in adults with attention-deficit hyperactivity disorder (ADHD). The underlying mechanisms might depend on mechanisms of exercise-mediated brain physiology. The study aims to investigate the effects of acute aerobic exercise on cortical excitability and cognitive performance, and the correlation between these phenomena in adults with ADHD. Twenty-six drug-naïve ADHD adults, and twenty-six age-, and gender-matched healthy controls were assessed with respect to cortical excitability and cognitive performance before and after acute aerobic exercise (a single session for 30 min) or a control intervention. The results show significantly enhanced intracortical facilitation (ICF) and decreased short intracortical inhibition (SICI) after aerobic exercise in healthy subjects. In contrast, SICI was significantly enhanced following acute aerobic exercise in ADHD. In ADHD, furthermore inhibitory control and motor learning were significantly improved after the acute aerobic exercise intervention. Alterations of SICI induced by aerobic exercise, and inhibitory control and motor learning improvement were significantly positively correlated in the ADHD group. Aerobic exercise had partially antagonistic effects in healthy controls, and ADHD patients. Furthermore, aerobic exercise-induced cognition-enhancing effects in ADHD depend on specific alterations of brain physiology, which differ from healthy humans.

Differential neurocognitive profiles in adult attention-deficit/hyperactivity disorder subtypes revealed by the Cambridge Neuropsychological Test Automated Battery

Adult attention-deficit/hyperactivity disorder (aADHD) represents a heterogeneous entity incorporating different subgroups in terms of symptomatology, course, and neurocognition. Although neurocognitive dysfunction is generally associated with aADHD, its severity, association with self-reported symptoms, and differences between subtypes remain unclear. We investigated 61 outpatients (65.6% male, mean age 31.5 ± 9.5) diagnosed using DSM-5 criteria together with age-, sex-, and education-matched healthy controls (HC) (n = 58, 63.8% male, mean age 32.3 ± 9.6). Neurocognitive alterations were assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB) and compared between groups using the generalized linear model (GLM) method. Multivariate effects were tested by principal component analysis combined with multivariate pattern analysis. Self-reported symptom severity was tested for correlations with neurocognitive performance. GLM analyses revealed nominally significant differences between the aADHD and HC groups in several domains, however, only the Rapid Visual Information Processing measures survived correction, indicating impaired sustained attention and response inhibition in the aADHD group. Comparison of the predominantly inattentive and the hyperactive-impulsive/combined subtypes yielded nominally significant differences with higher levels of dysfunction in the inattentive group. In the stepwise discriminant analysis aADHD and HC groups were best separated with 2 factors representing sustained attention and reaction time. We found only weak correlations between symptom severity and CANTAB factors. aADHD patients are neuropsychologically heterogeneous and subtypes show different neurocognitive profiles. Differences between the aADHD and HC groups were driven primarily by the inattentive subtype. Sustained attention and its factor derivative showed the most significant alterations in aADHD patients.

Maternal psychopathology is differentially associated with adolescent offspring neural response to reward given offspring ADHD risk

Reinforcement sensitivity is a hypothesized attention-deficit/hyperactivity disorder (ADHD) intermediate phenotype but its role in transgenerational transmission of ADHD-linked psychopathology risk is largely unknown. We examined, in a carefully phenotyped, N = 123 sample of adolescents (Mage = 15.27 years, SD = 0.984; 61.78% boys), whether (1) parental psychopathology is differentially associated with fMRI-indexed neural response to reward receipt and (2) both maternal and paternal psychopathology are associated with neural response to reward; across adolescents at-risk for and not at-risk for ADHD. Indices of parental psychopathology were differentially associated with adolescent offspring neural response to reward such that across measures, parental psychopathology was negatively or not associated with offspring superior frontal gyrus (SFG) response to reward receipt in adolescents at-risk for ADHD, but parental psychopathology was positively associated with offspring SFG response in adolescents not at-risk. Further, across measures, greater maternal psychopathology was associated with blunted adolescent SFG response to reward in adolescents at-risk for ADHD whereas greater maternal externalizing problems were linked to enhanced adolescent SFG response in adolescents not at-risk. Across measures, paternal psychopathology was not associated with adolescent response to reward, in either group. ADHD risk confers differential reward-related susceptibility to the effects of parental psychopathology. Results also show this association is nonspecific in terms of parental psychopathology type but is specific to maternal psychopathology.

Comparison of Cold and Cool Cognition in Children With and Without Attention Deficit-Hyperactivity Disorder (ADHD)

Children with ADHD suffer from impaired attentional, executive, and emotional processing. This study aimed to compare attentional and executive processing using (non)emotional stimuli in children with and without ADHD. Eighty-five children with ADHD and 72 matched typically developing children performed the Stroop, continuous performance, and Go/No-Go tasks using (non)emotional stimuli. Greater performance in selective attention, inhibitory control, and sustained attention was found in emotional stimuli compared to non-emotional stimuli in both groups. Emotional stimuli facilitated attentional and executive functions in children with and without ADHD. Impaired attentional and executive functions in children with ADHD are not valence-sensitive.

Hot and cold executive function among pediatric attention deficit hyperactivity disorder with and without coexisting oppositional defiant disorder

BACKGROUND

Executive function is a high-level set of cognitive processes related to goal-directed behaviors including two conceptual subtypes of hot (emotional) and cold (cognitive) executive function (to abbreviate EF). EF deficits in attention deficit hyperactivity disorder (ADHD) leads to significant social impairments in the home, school, and community. Today the type and the extent of executive function defects in ADHD are still debated in studies. We aimed to evaluate hot and cold executive function among medication-naive children with ADHD, with and without oppositional defiant disorder (ODD).

METHODS

Forty-five children including suffering ADHD with ODD (n = 15), without ODD (n = 15), or typically developed (TD, n = 15) participated in this cross-sectional study (the age of children was between 7 and 12 years old). The Child Symptom Inventory-4 (CSI-4) was used to screen behavioral and emotional symptoms. Wechsler Adult Intelligence Scale-Revised-Digit Span Task (WAIS-R-DST), Corsi Block Task (CBT), and Wisconsin Card Sorting Test (WCST) were used for assessing cold executive function. Assessing hot executive function was done with Delay Discounting Task (DDT) and Iowa Gambling Task (IGT).

RESULTS

Evaluating the cold executive function, total WAIS-R-DST score, Backward DST, total CBT score, and Backward CBT were significantly lower among ADHD than TD groups (p < 0.05). Assessing the hot executive function showed that the score of DDT and IGT was significantly lower among ADHD than TD groups (p < 0.05).

CONCLUSION

Both hot and cold executive functions are defective in children with ADHD, while the comorbid of ODD has no significant effect. We suggest the clinicians to consider cognitive rehabilitation interventions as a necessary treatment modality for ADHD patients.

Transcranial direct current stimulation enhances effort maintenance in ADHD

BACKGROUND

Youth with attention-deficit/hyperactivity disorder (ADHD) exhibit increased effort aversion, likely due to deficits in anticipatory dopamine firing. Previous research has shown that transcranial direct current stimulation (tDCS) targeting the right prefrontal cortex can enhance activity in dopaminergic meso-striatal regions. However, the extent to which this specific tDCS configuration effectively modulates effort behavior in anticipation of rewards in ADHD remains uncertain.

HYPOTHESIS

We expected an increase of effort maintenance and invigoration during and following our tDCS set-up compared to sham in subjects with ADHD.

METHODS

Twenty-four children and adolescents with ADHD (mean age: 11.6 years; 95 % CI [10.7, 12.4]) received 2 mA and sham tDCS for 20 min each. The anode was positioned over the ventromedial prefrontal cortex (PFC), while the cathode was placed over the right dorsolateral PFC, generating an electrical field with maximal strength in the right PFC. During and after the tDCS sessions, participants performed a button-pressing task aimed at earning delayed monetary rewards. Primary outcomes were effort maintenance (frequency of button presses) and invigoration (slopes of button presses), measuring motor task performance.

RESULTS

We observed a significant increase in effort maintenance both during (b = 2.66; p < 0.001) and after tDCS (b = 2.04; p= .007) compared to sham. No significant difference was found for invigoration during stimulation, while after bonferroni correction (p = 0.025) a non-significant decrease was found after tDCS compared to sham (b = -5.18; p = 0.041).

CONCLUSION

tDCS targeting the ventromedial PFC (anodal) and right dorsolateral PFC (cathodal) increases effort maintenance in children and adolescents with ADHD.

Computerized cognitive retraining (ReadON.ai) among children diagnosed with attention deficit hyperactivity disorder

Background

ADHD affects 8% of children and adolescents globally, marked by significant deficits in cognitive abilities, which leads to various emotional, behavioral, and adjustment issues. Traditional methods like medication and behavior therapy fall short in managing ADHD's cognitive domains, urging the adoption of innovative approaches like cognitive training programs specifically adopting the emerging technology such as ReadON.ai. However, the precise influence of computerized cognitive retraining on ADHD remains understudied.

Aim

To study the feasibility of computerized cognitive retraining (ReadON.ai) in enhancing cognitive abilities in children diagnosed with attention deficit hyperactivity disorder.

Materials and Methods

The study employs a pre- and post-intervention design including six participants (7-11 years), diagnosed with ADHD according to DSM-5 criteria. Each participant underwent 30 hours of computerized cognitive retraining (ReadON.ai) over ten weeks, targeting attention and concentration, working memory, memory and learning, perceptual abilities, and reasoning skills. Assessments before and after intervention included tools like Conners' 4TM Parent version and ReadON.ai CSA. Statistical analysis was conducted using IBM SPSS version 28.

Results

Paired t-test results revealed a significant difference in pre-test and post-test means of attention and concentration (t = -6.873, P < 0.001), working memory (t = -5.771, P < 0.001), learning and memory (t = -12.491, P < 0.001), perception (t = 14.398, P < 0.004), reasoning (t = -3.464, P < 0.018), hyperactivity (t = 11.073, P < 0.001), impulsivity (t = 11.948, P < 0.001), emotional dysregulation (t = 8.242, P < 0.001), anxious thoughts (t = 2.67 P = 0.219), depressed mood (t = 2.924, P = 0.020), school work (t = 7.387, P = 0.001) and peer interaction (t = 4.632, P = 0.006) with medium to large effect size.

Conclusion

Computerized cognitive retraining through ReadON.ai is feasible in enhancing cognitive abilities like attention and concentration, working memory, memory and learning, perception, and reasoning among children with ADHD.

Amygdala Volume is Associated with ADHD Risk and Severity Beyond Comorbidities in Adolescents: Clinical Testing of Brain Chart Reference Standards

Understanding atypicalities in ADHD brain correlates is a step towards better understanding ADHD etiology. Efforts to map atypicalities at the level of brain structure have been hindered by the absence of normative reference standards. Recent publication of brain charts allows for assessment of individual variation relative to age- and sex-adjusted reference standards and thus estimation not only of case-control differences but also of intraindividual prediction.

METHODS

Aim was to examine, whether brain charts can be applied in a sample of adolescents (N = 140, 38% female) to determine whether atypical brain subcortical and total volumes are associated with ADHD at-risk status and severity of parent-rated symptoms, accounting for self-rated anxiety and depression, and parent-rated oppositional defiant disorder (ODD) as well as motion.

RESULTS

Smaller bilateral amygdala volume was associated with ADHD at-risk status, beyond effects of comorbidities and motion, and smaller bilateral amygdala volume was associated with inattention and hyperactivity/impulsivity, beyond effects of comorbidities except for ODD symptoms, and motion.

CONCLUSIONS

Individual differences in amygdala volume meaningfully add to estimating ADHD risk and severity. Conceptually, amygdalar involvement is consistent with behavioral and functional imaging data on atypical reinforcement sensitivity as a marker of ADHD-related risk. Methodologically, results show that brain chart reference standards can be applied to address clinically informative, focused and specific questions.

Stimulant medications in children with ADHD normalize the structure of brain regions associated with attention and reward

Children with ADHD show abnormal brain function and structure. Neuroimaging studies found that stimulant medications may improve brain structural abnormalities in children with ADHD. However, prior studies on this topic were conducted with relatively small sample sizes and wide age ranges and showed inconsistent results. In this cross-sectional study, we employed latent class analysis and linear mixed-effects models to estimate the impact of stimulant medications using demographic, clinical measures, and brain structure in a large and diverse sample of children aged 9-11 from the Adolescent Brain and Cognitive Development Study. We studied 273 children with low ADHD symptoms and received stimulant medication (Stim Low-ADHD), 1002 children with high ADHD symptoms and received no medications (No-Med ADHD), and 5378 typically developing controls (TDC). After controlling for the covariates, compared to Stim Low-ADHD and TDC, No-Med ADHD showed lower cortical thickness in the right insula (INS, d = 0.340, PFDR = 0.003) and subcortical volume in the left nucleus accumbens (NAc, d = 0.371, PFDR = 0.003), indicating that high ADHD symptoms were associated with structural abnormalities in these brain regions. In addition, there was no difference in brain structural measures between Stim Low-ADHD and TDC children, suggesting that the stimulant effects improved both ADHD symptoms and ADHD-associated brain structural abnormalities. These findings together suggested that children with ADHD appear to have structural abnormalities in brain regions associated with saliency and reward processing, and treatment with stimulant medications not only improve the ADHD symptoms but also normalized these brain structural abnormalities.

Cognitive Correlates of Risky Decision-Making in Individuals with and without ADHD: A Meta-analysis

This meta-analytic study aims to investigate the cognitive correlates of risky decision-making in individuals with attention-deficit/hyperactivity disorder (ADHD) and typically developing (TD) individuals. A systematic analysis of existing literature was conducted, encompassing 38 studies (496 ADHD and 1493 TD). Findings revealed a consistent propensity for riskier decision-making in individuals with ADHD, supported by significant correlations with attention, cognitive flexibility, inhibitory control, time perception, and working memory. The study underscores the relevance of these cognitive functions in shaping decision-making tendencies, with nuanced patterns observed within the ADHD and TD subgroups. Individuals with ADHD often demonstrate altered patterns of correlation, reflecting the specific cognitive challenges characteristic of the disorder.

Transcranial direct current stimulation (tDCS) improves emotion regulation in children with attention-deficit hyperactivity disorder (ADHD)

Children with attention deficit/hyperactivity disorder (ADHD) typically exhibit difficulties in emotion regulation. It has been shown that the dorsolateral prefrontal cortex (dlPFC) and ventromedial prefrontal cortex (vmPFC) are crucially involved in these deficient processes. In this study, we aimed to explore the impact of electrical stimulation over the left dlPFC and right vmPFC on emotion regulation in children with ADHD. Twenty-four children with ADHD completed the Emotional Go/No-Go and Emotional 1-Back tasks while undergoing transcranial direct current stimulation (tDCS) in three separate sessions, each with a different electrode placement: anodal dlPFC (F3)/cathodal vmPFC (Fp2), anodal vmPFC (Fp2)/cathodal dlPFC (F3), and sham stimulation. During both real tDCS conditions, the accuracy of pre-potent inhibitory control and working memory performance improved, but not speed. This study provides evidence that the left dlPFC and the right vmPFC are involved in emotion regulation in ADHD.

Environmental predictors of children's executive functioning development

Executive functioning (EF) abilities develop through childhood, but this development can be impacted by various psychosocial environmental influences. Using longitudinal data from the Health Outcome and Measures of the Environment (HOME) Study, a prospective pregnancy and birth cohort study, we examined if psychosocial environmental factors were significant predictors of EF development. Study participants comprised 271 children and their primary caregivers (98.5% mothers) followed from birth to age 12. We identified four distinct EF developmental trajectory groups comprising a consistently impaired group (13.3%), a descending impairment group (27.7%), an ascending impairment group (9.95%), and a consistently not impaired group (49.1%). Higher levels of maternal ADHD and relational frustration appear to be risk factors for increased EF difficulty over time, while higher family income may serve as a protective factor delaying predisposed EF impairment. Important intervention targets might include teaching positive and effective parenting strategies to mothers whose children are at risk for EF dysfunction.

Brain iron concentration in childhood ADHD: A systematic review of neuroimaging studies

Iron deficiency may play a role in the pathophysiology of Attention Deficit/Hyperactivity Disorder (ADHD). Due to its preponderant function in monoamine catecholamine and myelin synthesis, brain iron concentration may be of primary interest in the investigation of iron dysregulation in ADHD. This study reviewed current evidence of brain iron abnormalities in children and adolescents with ADHD using magnetic resonance imaging methods, such as relaxometry and quantitative susceptibility mapping, to assess brain iron estimates. The study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A literature search was performed for studies published between January 1, 2008 and July 7, 2023 in Medline, Scopus and Proquest. Regions of interest, brain iron index values and phenotypical information were extracted from the relevant studies. Risk of bias was assessed using a modified version of the National Heart, Lung, and Blood Institute quality assessment tool. Seven cross-sectional studies comparing brain iron estimates in children with ADHD with neurotypical children were included. Significantly reduced brain iron content in medication-naïve children with ADHD was a consistent finding. Two studies found psychostimulant use may increase and normalize brain iron concentration in children with ADHD. The findings were consistent across the studies despite differing methodologies and may lay the early foundation for the recognition of a potential biomarker in ADHD, although longitudinal prospective neuroimaging studies using larger sample sizes are required. Lastly, the effects of iron supplementation on brain iron concentration in children with ADHD need to be elucidated.

The impact of time perception remediation on cold and hot executive functions and behavioral symptoms in children with ADHD

Children with ADHD struggle with impaired time management, indicating premature and temporally inadequate behavioral style. This study aimed to evaluate the impact of time perception remediation on hot and cold executive functions (EFs) and behavioral symptoms in children with ADHD. In this pilot study, an RCT design was employed to investigate the effects of the intervention on children with ADHD. The participants were assigned to either the control group (n = 15) or the intervention group (n = 13). The intervention group receive 10-12 sessions of program for attentive remediation of time perception (PART). Time perception, N-back, Wisconsin card sorting, Go/No-Go, balloon analog risk, Iowa gambling tasks, and Conner's parental rating scale were used for the assessment in three baseline, post-intervention, and follow-up sessions. Repeated measures ANOVAs were used for analysis. The results suggest improved time perception and risky decision making in intervention group. Working memory, inhibitory control, and cognitive flexibility did not improve after intervention. The behavioral symptoms ameliorated after intervention. Time perception is trainable in children with ADHD. This training effect transfers to hot EFs and behavioral symptoms, but not cold EFs. A cognitive model has been proposed based on the results of this studies and other cognitive training studies.

Dorsal Striatal Functional Connectivity and Repetitive Behavior Dimensions in Children and Youths With Neurodevelopmental Disorders

BACKGROUND

Impairing repetitive behaviors are one of the core diagnostic symptoms in autism spectrum disorder and obsessive-compulsive disorder, but they also manifest in attention-deficit/hyperactivity disorder. Although the dorsal striatal circuit has been implicated in repetitive behaviors, extensive heterogeneity in and cross-diagnostic manifestations of these behaviors have suggested phenotypic and likely neurobiological heterogeneity across neurodevelopmental disorders (NDDs).

METHODS

Intrinsic dorsal striatal functional connectivity was examined in 3 NDDs (autism spectrum disorder, obsessive-compulsive disorder, and attention-deficit/hyperactivity disorder) and typically developing control participants in a large single-cohort sample (N = 412). To learn how diagnostic labels and overlapping behaviors manifest in dorsal striatal functional connectivity measured with functional magnetic resonance imaging, the main and interaction effects of diagnosis and behavior were examined in 8 models (2 seed functional connectivity [caudate and putamen] × 4 sub-behavioral domains [sameness/ritualistic, self-injury, stereotypy, and compulsions]).

RESULTS

The obsessive-compulsive disorder group demonstrated distinctive patterns in visual and visuomotor coordination regions compared with the other diagnostic groups. Lower-order repetitive behaviors (self-injury and stereotypy) manifesting across all participants were implicated in regions involved in motor and cognitive control, although the findings did not survive effects of multiple comparisons, suggesting heterogeneity in these behavioral domains. An interaction between self-injurious behavior and an attention-deficit/hyperactivity disorder diagnosis were observed on caudate-cerebellum functional connectivity.

CONCLUSIONS

These findings confirmed high heterogeneity and overlapping behavioral manifestations in NDDs and their complex underlying neural mechanisms. A call for diagnosis-free symptom measures that can capture not only observable symptoms and severity across NDDs but also the underlying functions and motivations of such behaviors across diagnoses is needed.

Transcranial random noise stimulation (tRNS) improves hot and cold executive functions in children with attention deficit-hyperactivity disorder (ADHD)

Children with attention deficit-hyperactivity disorder (ADHD) have impaired hot and cold executive functions, which is thought to be related to impaired ventromedial and dorsolateral prefrontal cortex (vmPFC and dlPFC) functions. The present study aimed to assess the impact concurrent stimulation of dlPFC and vmPFC through transcranial random noise stimulation (tRNS), a non-invasive brain stimulation tool which enhances cortical excitability via application of alternating sinusoidal currents with random frequencies and amplitudes over the respective target regions on hot and cold executive functions. Eighteen children with ADHD received real and sham tRNS over the left dlPFC and the right vmPFC in two sessions with one week interval. The participants performed Circle Tracing, Go/No-Go, Wisconsin Card Sorting, and Balloon Analogue Risk Tasks during stimulation in each session. The results showed improved ongoing inhibition, prepotent inhibition, working memory, and decision making, but not set-shifting performance, during real, as compared to sham stimulation. This indicates that simultaneous stimulation of the dlPFC and the vmPFC improves hot and cold executive functions in children with ADHD.

Suboptimal decision making and interpersonal problems in ADHD: longitudinal evidence from a laboratory task

Over half of children with Attention-Deficit/Hyperactivity Disorder (ADHD) display interpersonal and social problems. Several lines of research suggest that suboptimal decision making, the ability to adjust choices to different risk-varying options, influences poorer choices made in social interactions. We thus measured decision making and its prediction of social problems longitudinally with the Cambridge Gambling Task in children with ADHD over four years. Children with ADHD had shown suboptimal decision making driven mainly by delay aversion at baseline and we expected this to be a stabile trait which would predict greater parent-reported social problems. From the baseline assessment (n = 70), 67% participated at the follow-up assessment, 21 from the ADHD group and 26 from the typically developing group. The mean age at the follow-up was 14.5 years old. The results confirmed our expectations that suboptimal decision making was a stabile trait in children and adolescents with ADHD. Although delay aversion did not differ from controls at follow-up it still proved to be the main longitudinal predictor for greater social problems. Our findings indicate that impulsivity in social interactions may be due to a motivational deficit in youth with ADHD.

Reduced dopamine transporter availability in drug-naive adult attention-deficit/hyperactivity disorder

Aim

This study aimed to clarify the abnormalities in dopamine transporter (DAT) availability in drug-naive adult patients with attention-deficit/hyperactivity disorder (ADHD) and the relationship between ADHD symptoms and abnormalities in DAT availability.

Methods

Single-photon emission tomography (SPECT) was performed using iodine-123-β-carbomethoxy-3β-(4-iodophenyltropane) (I-123 β CIT) as a tracer to measure in vivo DAT availability in 20 drug-naive patients with ADHD [mean age ± standard deviation (SD)]: 25 ± 3.44 years; male:female = 11:9] and 20 age- and sex-matched healthy controls (HCs) (mean age ± SD: 23.9 ± 2.27 years). Comparisons of DAT availability between HCs and adult patients with ADHD and the association between symptom severity and DAT availability within the ADHD group were analyzed using Statistical Parametric Mapping 12.

Results

Drug-naive adults with ADHD showed significantly reduced DAT availability in the bilateral nucleus accumbens compared with HCs. Correlation analyses revealed a negative correlation between the severity of inattentive symptoms in adult patients with ADHD and DAT availability in the bilateral heads of the caudate nucleus, indicating the association between severe inattentive symptoms and lower DAT availability in the caudate nucleus.

Conclusion

In drug-naive adult patients with ADHD, DAT availability was reduced in the nucleus accumbens, an important part of the reward system. This finding indicates the importance of the DAT in the reward system in the pathogenesis of ADHD. Inattentiveness was associated with DAT availability in the caudate nucleus, suggesting involvement of the cortico-striato-thalamo-cortical circuit.

Effectiveness of applied and casual games for young people's mental health: A systematic review of randomised controlled studies

Many youth experience mental health problems and digital games hold potential as mental health interventions. This systematic review provides an overview of randomised controlled studies assessing the effectiveness of digital applied and casual games for improving mental health in youth aged 6-24 years. A systematic search of PsycINFO, Web of Science and Pubmed yielded 145 eligible studies. Studies on (sub)clinical participant samples (n = 75) most often focused on attention-deficit/hyperactivity disorder (ADHD), autism and anxiety. Applied games were found most effective for improving social skills, verbal memory and anxiety, whereas casual games were found most effective for improving depression, anxiety and ADHD. Studies involving healthy youth (n = 70) were grouped into papers examining anxiety in medical settings, momentary effects on positive and negative affect, and papers employing a longitudinal design measuring mental health trait outcomes. Promising results were found for the use of games as distraction tools in medical settings, and for applied and casual games for improving momentary affect. Overall, our findings demonstrate the potential of digital games for improving mental health. Implications and recommendations for future research are discussed, such as developing evaluation guidelines, clearly defining applied games, harmonising outcome measures, including positive outcomes, and examining nonspecific factors that may influence symptom improvement as well.

Attention Training Improves Executive Functions and Ameliorates Behavioral Symptoms in Children with Attention-Deficit Hyperactivity Disorder: Implication of Tele-Cognitive-Rehabilitation in the Era of Coronavirus Disease

Background: Children with attention-deficit hyperactivity disorder (ADHD) struggle with impaired attention, leading to impaired executive function and behavioral symptoms. In this study, we aimed to evaluate the effect of attention training on executive functions and behavioral symptoms in children with ADHD, in a tele-cognitive-rehabilitation setting. Methods: Thirty children (mean age: 9.93 ± 1.68 years, 21 boys) with ADHD were randomly assigned to 2 equal groups of attention training and active control group. Attentive Rehabilitation and Improvement of Attention (ARIA) and a class of storytelling were used for intervention in two groups, in an online platform. Continuous performance test, one-back test, Wisconsin card sorting test (WCST), Conner's parent rating scale, and behavioral rating inventory of executive function (BRIEF) were used for assessment in three-baseline, postintervention, and follow-up sessions. Repeated measures analysis of variances were used for analysis. Results: ARIA leads to significant improvement in omission error (P < 0.001), commission error (P = 0.006), and response time (P = 0.005) of continuous performance test, cluster (P = 0.001), but not preservation error (P = 0.110) of WCST, accuracy of NBT (P = 0.004) and the score of Conner's parent rating scale (P < 0.001) and BRIEF (P < 0.001). These results indicate improved attention and executive functions, amelioration of ADHD symptoms, and improved behavioral performance. Conclusion: This study suggests that attention can be trained through tele-cognitive rehabilitation using a remediation program in children with ADHD. The effectiveness of this training can be confirmed by examining the transfer of training effects to other untrained cognitive domains, executive functions, symptoms of ADHD, and behavioral performance.

Brain mechanisms of temporal processing in impulsivity: Relevance to attention-deficit hyperactivity disorder

In this article, we critique the hypothesis that different varieties of impulsivity, including impulsiveness present in attention-deficit hyperactivity disorder, encompass an accelerated perception of time. This conceptualisation provides insights into how individuals with attention-deficit hyperactivity disorder have the capacity to maximise cognitive capabilities by more closely aligning themselves with appropriate environmental contexts (e.g. fast paced tasks that prevent boredom). We discuss the evidence for altered time perception in attention-deficit hyperactivity disorder alongside putative underlying neurobiological substrates, including a distributed brain network mediating time perception over multiple timescales. In particular, we explore the importance of temporal representations across the brain for time perception and symptom manifestation in attention-deficit hyperactivity disorder, including a prominent role of the hippocampus and other temporal lobe regions. We also reflect on how abnormalities in the perception of time may be relevant for understanding the aetiology of attention-deficit hyperactivity disorder and mechanism of action of existing medications.

Review of spatial disability in individuals with attention deficit-hyperactivity disorder: Toward spatial cognition theory

Spatial cognition is the ability to detect, process, integrate, and formulate the spatial aspects of the environment. Spatial abilities, as perceptual doorway of information processing, influence on higher cognitive functions. This systematic review aimed to explore impaired spatial ability in individuals with Attention Deficit-Hyperactivity Disorders (ADHD). The data from 18 empirical experiments that explored at least one factor of spatial ability in individuals with ADHD was collected in accordance with the PRISMA approach. This study discussed several determinants of impaired spatial ability, including factors, domains, tasks, and measures of spatial ability. Furthermore, the impact of age, gender, and comorbidities are discussed. Finally, a model was proposed to explain the impaired cognitive functions in children with ADHD based on spatial abilities.

Cardiovascular risk in adults with Delayed Sleep Phase Syndrome (DSPS) and Attention-Deficit/Hyperactivity Disorder (ADHD)

TRIAL REGISTRATION

FASE, https://www.trialregister.nl/, #NTR3831.

Fifty years of executive control research in attention-deficit/hyperactivity disorder:What we have learned and still need to know

For 50 years, attention-deficit/hyperactivity disorder (ADHD) has been considered a disorder of executive control (EC), the higher-order, cognitive skills that support self-regulation, goal attainment and what we generally call "attention." This review surveys our current understanding of the nature of EC as it pertains to ADHD and considers the evidence in support of eight hypotheses that can be derived from the EC theory of ADHD. This paper provides a resource for practitioners to aid in clinical decision-making. To support theory building, I draw a parallel between the EC theory of ADHD and the common gene-common variant model of complex traits such as ADHD. The conclusion offers strategies for advancing collaborative research.

Executive Functioning as a Predictor of Adverse Driving Outcomes in Teen Drivers With ADHD

OBJECTIVE

The present study examined the association between executive functioning (EF) and risky driving behaviors in teens with ADHD.

METHOD

Teens diagnosed with ADHD (n = 179; Mage = 17.4 years) completed two 15-min drives in a fixed-base driving simulator. EF was assessed using parent- and self-report Behavior Rating Inventory of Executive Functioning (BRIEF-2), a temporal reproduction task, and a Go/No-Go task (GNG). Driving outcomes included known predictors of crashes: count of long (>2 s) off-road glances, standard deviation (SD) of lane position (SDLP), mean speed, and SD speed. Generalized linear mixed models, controlling for intelligence and driving experience, were conducted.

RESULTS

Higher rates of GNG commission errors predicted higher rates of long off-road glances. Lower parent-rated EF and increased rates of GNG omission errors predicted SDLP. Higher rates of GNG commission errors also predicted faster average driving speed.

CONCLUSION

Heterogeneity in EF is associated with differences in teen ADHD risky driving behaviors.

Instrumental learning and behavioral persistence in children with attention-deficit/hyperactivity-disorder: does reinforcement frequency matter?

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.

Amphetamines Improve the Motivation to Invest Effort in Attention-Deficit/Hyperactivity Disorder

Prevailing frameworks propose that a key feature of attention-deficit/hyperactivity disorder (ADHD) is lower motivation. An important component of motivation is the willingness to engage in cognitively or physically effortful behavior. However, the degree to which effort sensitivity is impaired in ADHD has rarely been tested, and the efficacy of stimulant medication in ameliorating any such impairments is unclear. Here, we tested 20 individuals with ADHD (11 males, 9 females) who were managed with amphetamine-based medication (dexamfetamine, lisdexamfetamine), and 24 controls (8 males, 16 females). Individuals with ADHD were tested over two counterbalanced sessions, ON and OFF their usual amphetamine-based medication. In each session, participants performed an effort-based decision-making task, in which they were required to choose how much cognitive or physical effort they were willing to engage in return for reward. Our results revealed three main findings. First, individuals with ADHD had lower motivation relative to controls to invest effort in both the cognitive and physical domains. Second, amphetamine increased motivation uniformly across both domains. Finally, the net effect of amphetamine treatment was to mostly restore motivation across both domains of effort relative to healthy controls. These data provide clear evidence for a heightened sensitivity to both cognitive and physical effort in ADHD, and reveal the efficacy of amphetamine-based drugs in restoring effort sensitivity to levels similar to controls. These findings confirm the existence of reduced motivational drive in ADHD, and more broadly provide direct causal evidence for a domain-general role of catecholamines in motivating effortful behavior.SIGNIFICANCE STATEMENT A core feature of attention-deficit/hyperactivity disorder (ADHD) is thought to be a heightened aversion to effort. Surprisingly, however, the degree to which effort sensitivity is impaired in ADHD has rarely been tested. More broadly, the relative efficacy of catecholamines in motivating the investment of cognitive and physical effort is unclear. We tested 20 individuals with ADHD ON and OFF amphetamines, and compared their behavior on an effort-based decision-making task to 24 controls. When tested OFF medication, the ADHD group was less cognitively and physically motivated than controls. However, amphetamines led to a comparable increase in motivation across both domains. This demonstrates the efficacy of catecholamines in facilitating domain-general effort, and highlights the broader potential of such drugs to treat disorders of motivation.

Mechanisms of cognitive disinhibition explain individual differences in adult attention deficit hyperactivity disorder traits

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) in adults is strongly associated with psychiatric comorbidity and functional impairment. Here, we aimed to use a newly developed online cognitive battery with strong psychometric properties for measuring individual differences in three cognitive mechanisms proposed to underlie ADHD traits in adults: 1) attentional control - the ability to mobilize cognitive resources to stop a prepotent motor response; 2) information sampling/gathering - adequate sampling of information in a stimulus detection task prior to making a decision; and 3) shifting - the ability to adapt behavior in response to positive and negative contingencies.

METHODS

This cross-sectional and correlational study recruited 650 adults (330 males) aged 18-69 years (M = 33.06; MD = 31.00; SD = 10.50), with previously diagnosed ADHD (n = 329) and those from the general community without a history of ADHD (n = 321). Self-report measures of ADHD traits (i.e., inattention/disorganization, impulsivity, hyperactivity) and the cognitive battery were completed online.

RESULTS

Latent class analysis, exploratory structural equation modeling and factor mixture modeling revealed self-reported ADHD traits formed a unidimensional and approximately normally distributed phenotype. Bayesian structural equation modeling demonstrated that all three mechanisms measured by the cognitive battery, explained unique, incremental variance in ADHD traits, with a total of 15.9% explained in the ADHD trait factor.

CONCLUSIONS

Attentional control and shifting, as well as the less researched cognitive process of information gathering, explain individual difference variance in self-reported ADHD traits with potential to yield genetic and neurobiological insights into adult ADHD.

Neural symphony of risky decision making in children with ADHD: Insights from transcranial alternating current stimulation and cognitive modeling

BACKGROUND

The ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) are key brain regions involved in risky decision making, affected in individuals with attention deficit hyperactivity disorder (ADHD). This study aims to examine how entrainment of these areas impacts the process and outcome of risky decision making in children with ADHD.

METHODS

Eighteen children with ADHD performed the balloon analogue risk-taking task (BART) during five different sessions of tACS (1.5 mA, 6 Hz), separated by one-week intervals, via (1) two channels with synchronized stimulation over the left dlPFC and right vmPFC, (2) the same electrode placement with anti-phase stimulation, (3) stimulation over the left dlPFC only, (4) stimulation over right vmPFC only, and (5) sham stimulation. Four-parameter and constant-sensitivity models were used to model the data.

RESULTS

The study showed that synchronized stimulation was associated with a reduction in positive prior belief, risk propensity, and deterministic selection. Desynchronized stimulation was associated with accelerated learning from initial selections. Isolated stimulation of the dlPFC leads to riskier decision enhanced learning updates and risk propensity, whereas isolated stimulation of the vmPFC facilitated faster learning and increased probabilistic selection.

CONCLUSION

The results highlight the important roles of the dlPFC and vmPFC and their communication in decision making, showcasing their impact on various aspects of the decision-making process. The findings provide valuable insights into the complex interplay between cognitive and emotional factors in shaping our choices.

Default mode network connectivity and social dysfunction in children with Attention Deficit/Hyperactivity Disorder

Objective

Attention Deficit/Hyperactivity Disorder (ADHD) negatively affects social functioning; however, its neurological underpinnings remain unclear. Altered Default Mode Network (DMN) connectivity may contribute to social dysfunction in ADHD. We investigated whether DMN's dynamic functional connectivity (dFC) alterations were associated with social dysfunction in individuals with ADHD.

Methods

Resting-state fMRI was used to examine DMN subsystems (dorsal medial prefrontal cortex (dMPFC), medial temporal lobe (MTL)) and the midline core in 40 male ADHD patients (7-10 years) and 45 healthy controls (HCs). Connectivity correlations with symptoms and demographic data were assessed. Group-based analyses compared rsFC between groups with two-sample t-tests and post-hoc analyses.

Results

Social dysfunction in ADHD patients was related to reduced DMN connectivity, specifically in the MTL subsystem and the midline core. ADHD patients showed decreased dFC between parahippocampal cortex (PHC) and left superior frontal gyrus, and between ventral medial prefrontal cortex (vMPFC) and right middle frontal gyrus compared to HCs (MTL subsystem). Additionally, decreased dFC between posterior cingulate cortex (PCC), anterior medial prefrontal cortex (aMPFC), and right angular gyrus (midline core) was observed in ADHD patients relative to HCs. No abnormal connectivity was found within the dMPFC.

Conclusion

Preliminary findings suggest that DMN connectional abnormalities may contribute to social dysfunction in ADHD, providing insights into the disorder's neurobiology and pathophysiology.

Study protocol of a randomized trial of STRIPES: a schoolyear, peer-delivered high school intervention for students with ADHD

BACKGROUND

Youth with ADHD are at risk of academic impairments, dropping out of high school, and dysfunction in young adulthood. Interventions delivered early in high school could prevent these harmful outcomes, yet few high school students with ADHD receive treatment due to limited access to intervention providers. This study will test a peer-delivered intervention (STRIPES) for general education 9th grade students with impairing ADHD symptoms.

METHODS

A type 1 hybrid effectiveness-implementation design will be used to evaluate the effectiveness of STRIPES and explore the intervention's implementability. Analyses will test the impact of STRIPES vs. enhanced school services control on target mechanisms and determine whether differences in basic cognitive profiles moderate intervention response. The acceptability and feasibility of STRIPES and treatment moderators will also be examined.

DISCUSSION

This study will generate knowledge about the effectiveness and implementability of STRIPES, which will inform dissemination efforts in the future. A peer-delivered high school intervention for organization, time management, and planning skills can provide accessible and feasible treatment targeting declines in academic motivation, grades, and attendance during the ninth-grade year.

TRIAL REGISTRATION

This study is registered on OSF Registries (10.17605/OSF.IO/Q8V6S).