Cortical development in typically developing children with symptoms of hyperactivity and impulsivity: support for a dimensional view of attention deficit hyperactivity disorder

Glymphatic system dysfunction in adult ADHD: Relationship to cognitive performance

OBJECTIVES

While attention-deficit/hyperactivity disorder (ADHD) persists into adulthood, the relationship between glymphatic system function and cognitive performance in adult ADHD remains unclear. This study investigated the association between glymphatic system markers and cognitive outcomes in adults with ADHD.

METHODS

This case-control study includes 41 adults with ADHD and 108 age-matched healthy controls (HCs). Glymphatic function was evaluated using choroid plexus volume (CPV), diffusion tensor imaging along the perivascular space (DTI-ALPS) index and coupling between blood‑oxygen-level-dependent signals and cerebrospinal fluid signals (BOLD-CSF coupling). Cognitive performance was measured using standardized neuropsychological tests.

RESULTS

Compared with HCs, adults with ADHD exhibited significantly lower bilateral and whole-brain ALPS indices (P < 0.05). Although CPV was increased in the ADHD group, this difference did not reach statistical significance, and no significant differences were observed in BOLD-CSF coupling between the two groups. Furthermore, whole-brain ALPS indices were positively associated with visual memory performance (r = 0.422, P = 0.005), an effect that was more pronounced in the right hemisphere (r = 0.458, P = 0.002).

LIMITATIONS

The cross-sectional design limits causal inferences, and the effects of medication were not fully accounted for.

CONCLUSIONS

These findings identify an association between glymphatic dysfunction and cognitive impairment in adults with ADHD. The observed correlation suggests that alterations in glymphatic function may underlie ADHD-related cognitive deficits. Targeting these pathways could provide novel therapeutic opportunities in the management of adult ADHD.

Neural basis of the association between future time perspective and ADHD characteristics: functional connectivity between Left inferior parietal lobule and mPFC

ADHD is a neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity, leading to ongoing challenges in academic, career, and social adaptation. Previous research indicated that individuals with higher levels of future time perspective (FTP) tend to exhibit lower ADHD traits. However, little is known about the neural substrates between the relationship of FTP and ADHD traits. To address this question, we adopted voxel-based morphometry (VBM) and resting-state functional connectivity (RSFC) analyses in a sample of 240 participants to investigate the neural substrates involved in the relationship between FTP and ADHD traits. Behavioral results demonstrated FTP was significantly negatively correlated with attention deficit (AD), hyperactivity-impulsivity disorder (HD) traits respectively. VBM analysis revealed a significant positive correlation between FTP and gray matter volume (GMV) in the superior medial frontal gyrus (SMFG) and left precentral gyrus (PG), while FTP was negatively related to GMV in the left inferior parietal lobule (IPL) and left superior temporal gyrus (STG). Furthermore, RSFC results indicated individuals with higher levels of FTP exhibited greater functional connectivity between the IPL and both the dorsomedial prefrontal cortex (dmPFC) and the ventromedial prefrontal cortex (vmPFC). More importantly, mediation analysis revealed that FTP fully mediated the relationship between the functional connectivity of IPL-dmPFC and IPL-vmPFC with AD traits, and the relationship between the functional connectivity of IPL-vmPFC and HD traits. Overall, this study highlights the crucial role of brain circuits involved in planning regulation, goal execution, and value evaluation in the relationship between FTP and ADHD symptoms.

Motor skills and neurological soft signs: Are they only clinical differences or reflection of distinct etiopathogenesis in tic disorder and primary stereotypic movement disorder?

BACKGROUND

While tic disorders and stereotypic movement disorder are commonly comorbid in pediatric clinics, their clinical and etiological differences remain poorly understood.

OBJECTIVES

We aimed to investigate the clinical features that differentiate between tic disorders and primary stereotypic movement disorder by evaluating neurological soft signs and motor skills.

METHODS

The Kiddie-Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version DSM-5 and Sociodemographic and Clinical Data Form were administered to the children. The clinician completed Yale Global Tic Severity Scale, Repetitive Behavior Scale-Revised and Neurological Evaluation Scale. Nine-Hole Peg Test was used for fine motor skills, 1-Minute Sit-to-Stand Test for gross motor skills, Flamingo Balance Test for static balance, Finger-to-Nose Test for bilateral coordination. Parents completed the Conners Parent Rating Scale-Revised Short Form and the Revised Developmental Coordination Disorder Questionnaire.

RESULTS

Our sample consisted of 20 tic disorders, 20 primary stereotypic movement disorder, 13 attention deficit hyperactivity disorder patients, and 20 healthy controls. Sequencing of the complex motor acts scores of Neurological Evaluation Scale were significantly higher in the primary stereotypy group than in healthy controls. The primary stereotypy group demonstrated significantly lower dominant hand performance on the Nine-Hole Peg Test than the tic group. Children with stereotypy had significantly lower scores of 1-min sit-to-stand test; higher total and subscale scores of Revised Developmental Coordination Disorder Questionnaire. and higher developmental coordination disorder risk than healthy controls.

CONCLUSIONS

Our findings offer valuable insights into the distinct etiopathogenesis of tic disorders and primary stereotypic movement disorder, providing a foundation for future neurobiological research.

Psychometric Properties and Adaptation of the Parent-Report Version of the Barkley Deficits in Executive Functioning Short-Form Scale in Spanish Children

INTRODUCTION

Executive functioning (EF) encompasses essential cognitive abilities crucial for self-regulation and goal achievement. The Barkley Deficits in Executive Functioning Scale in Children and Adolescents (BDEFS-CA) is a widely utilized tool for assessing EF in youth, with the short-form parent-reported version comprising twenty items.

OBJECTIVE

This study aims to assess the psychometric properties of the Spanish version of the BDEFS-CA Short-Form in children, including factor structure, reliability, validity, and sex invariance.

METHOD

Following transcultural adaptation by bilingual experts, the Spanish version was administered to 377 parents of children aged 6-12. Convergent validity was assessed using the Childhood Executive Functioning Inventory (CHEXI).

RESULTS

Results from confirmatory factor analysis supported a bifactor model encompassing a general EF factor and specific subscales (Comparative Fit Index = 0.984; Root-Mean-Square Error of Approximation = 0.048; Standardized Root Mean Square Residual = 0.024): time management (TM), problem solving/organization (PS), inhibition (IN), motivation (MOT), and emotional regulation (ER). High internal consistency was observed for both the general EF factor (α/ω = 0.956) and its subscales (TM: α/ω > 0.89, PS: α/ω > 0.93, IN: α/ω > 0.94, MOT: α/ω > 0.91, ER: α/ω > 0.93). Convergent validity was confirmed through strong correlations between BDEFS-CA and CHEXI scores (r = 0.552-0.892, P < 0.001). Sex invariance analysis revealed similar factor structures for men and women.

CONCLUSIONS

The Spanish adaptation of the BDEFS-CA Short-Form demonstrates strong psychometric properties, making it a reliable tool for assessing EF in Spanish-speaking children. Its simplicity and suitability suggest potential use by adults for gathering children's information.

Is poor control over thoughts and emotions related to a higher tendency to delay tasks? The link between procrastination, emotional dysregulation and attentional control

A tendency to procrastinate has previously been linked to low attentional control and poor emotion regulation skills. Building upon these findings, in the present study we investigated whether the relationship between procrastination and attention can be corroborated and explained by emotion dysregulation and dispositional spontaneous mind-wandering. University students completed questionnaires along with the Attentional Networks Test for Interactions and Vigilance - executive and arousal components. The results showed that trait procrastination is inversely related to some indices of executive and arousal vigilance. Interestingly, the direct effects between trait procrastination and vigilance scores disappeared when emotion dysregulation or dispositional spontaneous mind-wandering were included in the model. Obtained findings suggest that difficulties in managing emotional reactions and poor control over the focus of one's thoughts might explain the relationship between low attentional control and increased chronic procrastination.

Exploring Virtual Reality and Exercise Simulator Interventions in Patients With Attention Deficit Hyperactivity Disorder: Comprehensive Literature Review

BACKGROUND

This review explores virtual reality (VR) and exercise simulator-based interventions for individuals with attention-deficit/hyperactivity disorder (ADHD). Past research indicates that both VR and simulator-based interventions enhance cognitive functions, such as executive function and memory, though their impacts on attention vary.

OBJECTIVE

This study aimed to contribute to the ongoing scientific discourse on integrating technology-driven interventions into the management and evaluation of ADHD. It specifically seeks to consolidate findings on how VR and exercise simulators may support individuals with ADHD, acknowledging associated challenges and implications inherent in both technological approaches.

METHODS

This research looks at existing literature to examine the potential efficacy of VR and exercise simulator-based interventions for individuals with ADHD. It evaluates the capacity of these interventions to address specific challenges along with an emphasis on the adjustments for accommodating unique user behaviors. Additionally, it underscores the limited exploration of user perceptions of exercise simulator-based interventions and the undervalued role of motor function in both ADHD assessment and symptom management.

RESULTS

The findings of this scoping review reveal that, while these interventions enhance user motivation and enjoyment, certain challenges resist modification through technology. Furthermore, this study explores the intricate complexities involved in customizing these technologies to accommodate the diverse aspects of user behavior and highlights the potential limitations in the use of VR.

CONCLUSIONS

This scoping review contributes to the ongoing research on enhancing interventions to support individuals with ADHD. It advocates for participant-centric approaches that aim to optimize both cognitive and motor outcomes while prioritizing the enhancement of user experiences. This study emphasizes the need for a comprehensive approach to interventions, recognizing the relationship between cognitive and motor abilities, and calls for improving technological interventions to address the varied needs of individuals with ADHD.

Rare Variant Analyses in Ancestrally Diverse Cohorts Reveal Novel ADHD Risk Genes

Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder, but its genetic architecture remains incompletely characterized. Rare coding variants, which can profoundly impact gene function, represent an underexplored dimension of ADHD risk. In this study, we analyzed large-scale DNA sequencing datasets from ancestrally diverse cohorts and observed significant enrichment of rare protein-truncating and deleterious missense variants in highly evolutionarily constrained genes. This analysis identified 15 high-confidence ADHD risk genes, including the previously implicated KDM5B. Integrating these findings with genome-wide association study (GWAS) data revealed nine enriched pathways, with strong involvement in synapse organization, neuronal development, and chromatin regulation. Protein-protein interaction analyses identified chromatin regulators as central network hubs, and single-cell transcriptomic profiling confirmed their expression in neurons and glial cells, with distinct patterns in oligodendrocyte subtypes. These findings advance our understanding of the genetic architecture of ADHD, uncover core molecular mechanisms, and provide promising directions for future therapeutic development.

Adolescent Impulsivity and Emotion Dysregulation: The Moderating Role of Parental Socialization of Negative Emotions

This study investigated whether parental socialization of negative emotions moderated the relationship between adolescents' low executive function or high impulsivity and their current or subsequent emotion dysregulation. Emotion dysregulation, characterized by difficulties in managing the intensity and duration of emotions, is a transdiagnostic factor linked to adverse outcomes. Youth with poor executive functioning and/or high impulsivity are at risk for emotion dysregulation; however, the role of parenting in influencing this trajectory warrants exploration. Self-report and parent-report measures were collected from 116 adolescents and their parents, assessing adolescent executive function (BRIEF), adolescent impulsivity (S-UPP-S), adolescents' perceptions of their parent's responses to negative emotions (CCNES-AP), and adolescent emotion regulation difficulties (DERS). Moderation analyses revealed that high levels of unsupportive parental responses significantly moderated the effect of high impulsivity on emotion dysregulation (b = 10.27, p = .031) cross-sectionally.

Neural markers of error processing relate to task performance, but not to substance-related risks and problems and externalizing problems in adolescence and emerging adulthood

Detecting errors and adapting behavior accordingly constitutes an integral aspect of cognition. Previous studies have linked neural correlates of error processing (e.g., error-related negativity (ERN) and error-related positivity (Pe)) to task performance and broader behavioral constructs, but few studies examined how these associations manifest in adolescence. In this study, we examined neural error processing markers and their behavioral associations in an adolescent/emerging adult sample (N = 143, Mage = 18.0 years, range 11-25 years), employing a stop-signal task. Linear regressions were conducted using bootstrap resampling to explore associations between ERN/Pe peak amplitudes and latencies, stop accuracy, stop-signal reaction time (SSRT), and post-error slowing, as well as self-reported substance-related risks and problems and externalizing problems. After adjusting for age and sex, smaller frontocentral Pe amplitude and later Pe latency were associated with longer SSRT, and later Pe latency was associated with lower stop accuracy. This might indicate that the Pe, which is thought to reflect conscious error processing, reflects task performance on a response inhibition task better than the ERN, which reflects subconscious error processing. After correcting for multiple testing, there were no associations between ERN/Pe parameters and substance-related or externalizing problems, and no age interactions for these associations were detected.

Current Perspectives on Attention-deficit Hyperactivity Disorder

Attention-deficit hyperactivity disorder (ADHD) is a neurobiological and neurodevelopmental disorder with an idiosyncratic genetic base. ADHD presents various characteristics, such as inattention, hyperactivity, and impulsivity. Over the period, ADHD leads to noticeable functional disability. A five- to ten-fold progressed risk of disorder development is observed in the populations with familial history of ADHD. The abnormal structure of the brain in ADHD results in altered neural mechanisms, such as cognition, attention, and memorial function. The mesolimbic, nigrostriatal, and mesocortical pathways in the brain get affected by the deterioration of the levels of dopamine. The hypothesis of dopamine in ADHD and its etiopathology suggests that detained attention and impaired arousal functions are due to reduced levels of dopamine. The quickest way to improve strategical treatment is by clarifying the etiological aspects of ADHD and identifying the underlying mechanisms of pathophysiology, which will assist in exploring the biomarkers for better diagnosis. The implementation of life course theory is a very important research principle announced by Grand Challenges in Global Health Initiative (GCMHI). Long-term research is needed to define the progression of ADHD. Interdisciplinary collaborations promise a great future for research innovations in ADHD.

Effects of mind-body exercise on individuals with ADHD: a systematic review and meta-analysis

Objective

To explore the effects of mind-body exercise (MBE) on ADHD through a systematic review and meta-analysis.

Methods

After identifying relevant search keywords based on the study's technical terminology, research articles were retrieved from five databases. Two researchers independently screened the results to select studies that met the inclusion criteria. A random-effects model was used to conduct a meta-analysis on the included studies.

Results

The findings indicate that MBE interventions significantly improved attention in individuals with ADHD [SMD=-0.97, 95% CI (-1.56, -0.39), P < 0.05]. However, the meta-analysis found no evidence that MBE improved executive function, emotional issues, or hyperactivity/impulsivity in ADHD patients.

Conclusions

MBE is beneficial for attention improvement in ADHD patients. However, further evidence is needed to support its efficacy as an adjunctive treatment for other symptoms.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023447510.

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.

Attention-deficit/hyperactivity disorder (ADHD) in adults: a multilayered approach to a serious disorder of inattention to the future

Attention-deficit/hyperactivity disorder (ADHD) affects people of all ages, yet its presentation varies as the person matures and social demands increase from childhood into adulthood. Interestingly, when analyzing the disorder in adults, it is not immediately clear what the 'attention deficit' in the ADHD denomination exactly means. Adults with ADHD have a broad range of difficulties, far beyond an attentional deficit, that impact negatively their social functioning and often lead to failures in all walks of life. Therefore, in this review, I attempt to reconcile the notion of attention deficit with the protean manifestations of ADHD in adults through a proposal that ADHD symptoms have as a common denominator an inattention to the future. I build this construct through a multilayered approach, progressing from the epidemiological and clinical considerations for Diagnostic and Statistical Manual of Mental Disorders (DSM) diagnosis, to a deeper understanding of the disorder, discussing how these patients fail to anchor the present into the future (i.e., to be attentive to future consequences), thus failing to approximate future goals from present action. Integrating cognitive observations with imaging abnormalities, it is possible to propose that ADHD in adults is perhaps the most prevalent frontal lobe disorder in humans, ultimately impacting upon psychosocial management and treatment strategies.

Cortical grey matter volume differences in children with developmental coordination disorder compared to typically developing children

Introduction

The cause of Developmental Coordination Disorder (DCD) is unknown, but neuroimaging evidence suggests that DCD may be related to altered brain development. Children with DCD show less structural and functional connectivity compared to typically developing (TD) children, but few studies have examined cortical volume in children with DCD. The purpose of this study was to investigate cortical grey matter volume using voxel-based morphometry (VBM) in children with DCD compared to TD children.

Methods

This cross-sectional study was part of a larger randomized-controlled trial (ClinicalTrials.gov ID: NCT02597751) that involved various MRI scans of children with/without DCD. This paper focuses on the anatomical scans, performing VBM of cortical grey matter volume in 30 children with DCD and 12 TD children. Preprocessing and VBM data analysis were conducted using the Computational Anatomy Tool Box-12 and a study-specific brain template. Differences between DCD and TD groups were assessed using a one-way ANOVA, controlling for total intracranial volume. Regression analyses examined if motor and/or attentional difficulties predicted grey matter volume. We used threshold-free cluster enhancement (5,000 permutations) and set an alpha level of 0.05. Due to the small sample size, we did not correct for multiple comparisons.

Results

Compared to the TD group, children with DCD had significantly greater grey matter in the left superior frontal gyrus. Lower motor scores (meaning greater impairment) were related to greater grey matter volume in left superior frontal gyrus, frontal pole, and right middle frontal gyrus. Greater grey matter volume was also significantly correlated with higher scores on the Conners 3 ADHD Index in the left superior frontal gyrus, superior parietal lobe, and precuneus. These results indicate that greater grey matter volume in these regions is associated with poorer motor and attentional skills.

Discussion

Greater grey matter volume in the left superior frontal gyrus in children with DCD may be a result of delayed or absent healthy cortical thinning, potentially due to altered synaptic pruning as seen in other neurodevelopmental disorders. These findings provide further support for the hypothesis that DCD is related to altered brain development.

The interplay between ADHD and school shift on educational outcomes in children and adolescents: A cross-sectional and longitudinal analysis

Many countries implement a double-shift schooling system, offering morning or afternoon shifts, driven by diverse factors. Young people with ADHD may face educational problems attending morning shifts compared to afternoon shifts. To investigate this, we used data from a Brazilian school-based cohort (n = 2.240, 6-14 years old, 45.6% female; 50.2% in the morning shift; 11.2% with ADHD). ADHD was determined by child psychiatrists using semi-structured interview. Educational outcomes were measured cross-sectionally and three years later (80% retention) and included reading and writing ability, performance in school subjects, and any negative school events (repetition, suspension, or dropout). Generalized regression models tested the interaction between ADHD and school shift and were adjusted for age, sex, race/ethnicity, intelligence, parental education, socioeconomic status, and site. Attrition was adjusted with inverse probability weights. We used two dimensional measures of attentional problems as sensitivity analysis. ADHD and morning shift were independently associated with lower reading and writing ability and with higher odds for negative school events cross sectionally. ADHD independently predicted lower performance in school subjects and higher negative school events at follow-up. Interaction was found only at the cross-sectional level in a way that those studying in the afternoon present better educational outcomes compared with those studying in the morning only if they have lower ADHD symptom. Thus, ADHD was not associated with poorer educational outcomes among those studying in the morning. However, participants studying in the afternoon with lower levels of attentional problems presented better educational, despite these associations fade away over time.

The effects of chiropractic adjustment on inattention, hyperactivity, and impulsivity in children with attention deficit hyperactivity disorder: a pilot RCT

Background

Attention deficit hyperactivity disorder (ADHD) is a neurobiological disorder characterized by inattention, hyperactivity, and impulsivity. We hypothesized that chiropractic adjustments could improve these symptoms by enhancing prefrontal cortex function. This pilot study aimed to explore the feasibility and efficacy of 4 weeks of chiropractic adjustment on inattention, hyperactivity, and impulsivity in children with ADHD.

Methods

67 children with ADHD were randomly allocated to receive either chiropractic adjustments plus usual care (Chiro+UC) or sham chiropractic plus usual care (Sham+UC). The Vanderbilt ADHD Diagnostic Teacher Rating Scale (VADTRS), Swanson, Nolan and Pelham Teacher and Parents Rating Scale (SNAP-IV), and ADHD Rating Scale-IV were used to assess outcomes at baseline, 4 weeks, and 8 weeks. Feasibility measures such as recruitment, retention, blinding, safety, and adherence were recorded. Linear mixed regression models were used for data analysis.

Results

56 participants (mean age ± SD: 10.70 ± 3.93 years) were included in the analysis. Both the Chiro+UC and Sham+UC groups showed significant improvements in total and subscale ADHD scores at 4 weeks and 8 weeks. However, there were no significant differences between the two groups.

Conclusion

This pilot study demonstrated that it was feasible to examine the effects of chiropractic adjustment when added to usual care on ADHD outcomes in children. While both groups showed improvements, the lack of significant between-group differences requires caution in interpretation due to the small sample size. Further research with larger samples and longer follow-up periods is needed to conclusively evaluate the effects of chiropractic adjustments on ADHD in children.

Examining the interaction between prenatal stress and polygenic risk for attention-deficit/hyperactivity disorder on brain growth in childhood: Findings from the DREAM BIG consortium

This study explored the interactions among prenatal stress, child sex, and polygenic risk scores (PGS) for attention-deficit/hyperactivity disorder (ADHD) on structural developmental changes of brain regions implicated in ADHD. We used data from two population-based birth cohorts: Growing Up in Singapore Towards healthy Outcomes (GUSTO) from Singapore (n = 113) and Generation R from Rotterdam, the Netherlands (n = 433). Prenatal stress was assessed using questionnaires. We obtained latent constructs of prenatal adversity and prenatal mood problems using confirmatory factor analyses. The participants were genotyped using genome-wide single nucleotide polymorphism arrays, and ADHD PGSs were computed. Magnetic resonance imaging scans were acquired at 4.5 and 6 years (GUSTO), and at 10 and 14 years (Generation R). We estimated the age-related rate of change for brain outcomes related to ADHD and performed (1) prenatal stress by sex interaction models, (2) prenatal stress by ADHD PGS interaction models, and (3) 3-way interaction models, including prenatal stress, sex, and ADHD PGS. We observed an interaction between prenatal stress and ADHD PGS on mean cortical thickness annual rate of change in Generation R (i.e., in individuals with higher ADHD PGS, higher prenatal stress was associated with a lower rate of cortical thinning, whereas in individuals with lower ADHD PGS, higher prenatal stress was associated with a higher rate of cortical thinning). None of the other tested interactions were statistically significant. Higher prenatal stress may promote a slower brain developmental rate during adolescence in individuals with higher ADHD genetic vulnerability, whereas it may promote a faster brain developmental rate in individuals with lower ADHD genetic vulnerability.

Is Attention-Deficit/Hyperactivity Disorder (ADHD) a Dimension or a Category? What Does the Relationship Between ADHD Traits and Psychosocial Quality of Life Tell Us?

OBJECTIVE

The question of whether attention-deficit/hyperactivity disorder (ADHD) is a discrete category or a continuous dimension remains clinically relevant. We report the first examination of this question from the viewpoint of the relationship between ADHD traits and psychosocial quality of life (QoL), and whether the level of QoL declines markedly around a certain high ADHD trait range suggestive of a categorical boundary.

METHODS

Parents/caregivers of 1,967 schoolchildren aged 6 to 11 from the general population completed the Pediatric Quality of Life Inventory and the ADHD-Rating Scale IV. Piecewise linear and non-linear regression analyses were performed.

RESULTS

No evidence for a non-linear association or an abrupt change in the rate of decrease in QoL was observed in the high end of the ADHD traits continuum. Instead, the relationship was consistent with linearity.

CONCLUSION

Psychosocial QoL gradually declines in a linear manner as ADHD trait levels increase providing further support for a dimensional model.

Functional connectivity development along the sensorimotor-association axis enhances the cortical hierarchy

Human cortical maturation has been posited to be organized along the sensorimotor-association axis, a hierarchical axis of brain organization that spans from unimodal sensorimotor cortices to transmodal association cortices. Here, we investigate the hypothesis that the development of functional connectivity during childhood through adolescence conforms to the cortical hierarchy defined by the sensorimotor-association axis. We tested this pre-registered hypothesis in four large-scale, independent datasets (total n = 3355; ages 5-23 years): the Philadelphia Neurodevelopmental Cohort (n = 1207), Nathan Kline Institute-Rockland Sample (n = 397), Human Connectome Project: Development (n = 625), and Healthy Brain Network (n = 1126). Across datasets, the development of functional connectivity systematically varied along the sensorimotor-association axis. Connectivity in sensorimotor regions increased, whereas connectivity in association cortices declined, refining and reinforcing the cortical hierarchy. These consistent and generalizable results establish that the sensorimotor-association axis of cortical organization encodes the dominant pattern of functional connectivity development.

Transdiagnostic symptom of depression and anxiety associated with reduced gray matter volume in prefrontal cortex

Dimensional models of psychopathology may provide insight into mechanisms underlying comorbid depression and anxiety and improve specificity and sensitivity of neuroanatomical findings. The present study is the first to examine neural structure alterations using the empirically derived Tri-level Model. Depression and anxiety symptoms of 269 young adults were assessed using the Tri-level Model dimensions: General Distress (transdiagnostic depression and anxiety symptoms), Anhedonia-Apprehension (relatively specific depression symptoms), and Fears (specific anxiety symptoms). Using structural MRI, gray matter volumes were extracted for emotion generation (amygdala, nucleus accumbens) and regulation (orbitofrontal, ventrolateral, and dorsolateral prefrontal cortex) regions, often implicated in depression and anxiety. Each Tri-level symptom was regressed onto each region of interest, separately, adjusting for relevant covariates. General Distress was significantly associated with smaller gray matter volumes in bilateral orbitofrontal cortex and ventrolateral prefrontal cortex, independent of Anhedonia-Apprehension and Fears symptom dimensions. These results suggests that prefrontal alterations are associated with transdiagnostic dysphoric mood common across depression and anxiety, rather than unique symptoms of these disorders. Additionally, no regions of interest were associated with Anhedonia-Apprehension or Fears, highlighting the importance of studying transdiagnostic features of depression and anxiety. This has implications for understanding mechanisms of and interventions for depression and anxiety.

Adult ADHD: it is old and new at the same time - what is it?

Even though the number of studies aiming to improve comprehension of ADHD pathology has increased in recent years, there still is an urgent need for more effective studies, particularly in understanding adult ADHD, both at preclinical and clinical levels, due to the increasing evidence that adult ADHD is highly distinct and a different entity from childhood ADHD. This review paper outlines the symptoms, diagnostics, and neurobiological mechanisms of ADHD, with emphasis on how adult ADHD could be different from childhood-onset. Data show a difference in the environmental, genetic, epigenetic, and brain structural changes, when combined, could greatly impact the behavioral presentations and the severity of ADHD in adults. Furthermore, a crucial aspect in the quest to fully understand this disorder could be through longitudinal analysis. In this way, we will determine if and how the pathology and pharmacology of ADHD change with age. This goal could revolutionize our understanding of the disorder and address the weaknesses in the current clinical classification systems, improving the characterization and validity of ADHD diagnosis, specifically those in adults.

Prefrontal cortex structural and developmental associations with callous-unemotional traits and aggression

Youths with high levels of callous-unemotional (CU) traits and aggression are at an increased risk for developing antisocial behaviours into adulthood. In this population, neurostructural grey matter abnormalities have been observed in the prefrontal cortex. However, the directionality of these associations is inconsistent, prompting some to suggest they may vary across development. Although similar neurodevelopmental patterns have been observed for other disorders featuring emotional and behavioural dysregulation, few studies have tested this hypothesis for CU traits, and particularly not for aggression subtypes. The current study sought to examine grey matter correlates of CU traits and aggression (including its subtypes), and then determine whether these associations varied by age. Fifty-four youths (10-19 years old) who were characterized for CU traits and aggression underwent MRI. Grey matter volume and surface area within the anterior cingulate cortex was positively associated with CU traits. The correlation between CU traits and medial orbitofrontal cortex (mOFC) volume varied significantly as a function of age, as did the correlation between reactive aggression and mOFC surface area. These associations became more positive with age. There were no significant findings for proactive/total aggression. Results are interpreted considering the potential for delayed cortical maturation in youths with high CU traits/aggression.

Comparing mental health semi-structured diagnostic interviews and symptom checklists to predict poor life outcomes: an 8-year cohort study from childhood to young adulthood in Brazil

BACKGROUND

Semi-structured diagnostic interviews and symptom checklists present similar internal reliability. We aim to investigate whether they differ in predicting poor life outcomes in the transition from childhood to young adulthood.

METHODS

For this longitudinal study, we used data from the Brazilian High Risk Cohort Study for Childhood Mental Health Conditions. Eligible participants were aged 6-14 years on the day of study enrolment (January to February, 2010) and were enrolled in public schools by a biological parent in Porto Alegre and São Paulo, Brazil. 2511 young people and their caregivers were assessed at baseline in 2010-11, and 1917 were assessed 8 years later (2018-19; 76·3% retention). Clinical thresholds were derived using semi-structured parent-report interview based on the Diagnostic and Statistical Manual of Mental Disorders, according to the Developmental and Well-being Assessment (DAWBA), and clinical scores as defined by the Child Behavior Checklist (CBCL; T-score ≥70 considered positive caseness). At 8 years, participants were assessed for a composite life-threatening outcome (a composite of death, suicide attempts, severe self-harm, psychiatric inpatient admission, or emergency department visits) and a composite poor life chances outcome (a composite of any criminal conviction, substance misuse, or school dropout). We evaluated the accuracy of DAWBA and CBCL to predict these outcomes. Logistic regression models were adjusted for age, sex, race or ethnicity, study site, and socioeconomic class.

FINDINGS

DAWBA and CBCL had similar sensitivity, specificity, predictive values, and test accuracy for both composite outcomes and their components. Any mental health problem, as classified by DAWBA and CBCL, was independently associated with the composite life-threatening outcome (DAWBA adjusted odds ratio 1·62, 95% CI 1·20-2·18; CBCL 1·66, 1·19-2·30), but only CBCL independently predicted poor life chances (1·56, 1·19-2·04). Participants classified by both approaches did not have higher odds of the life-threatening outcome when compared with participants classified by DAWBA or CBCL alone, nor for the poor life chances outcome when compared with those classified by CBCL alone.

INTERPRETATION

Classifying children and adolescents based on a semi-structured diagnostic interview was not statistically different to symptom checklist in terms of test accuracy and predictive validity for relevant life outcomes. Classification based on symptom checklist might be a valid alternative to costly and time-consuming methods to identify young people at risk for poor life outcomes.

FUNDING

Conselho Nacional de Desenvolvimento Científico e Tecnológico; Fundação de Amparo à Pesquisa do Estado de São Paulo; and Medical Research Council, European Research Council.

TRANSLATION

For the Portuguese translation of the abstract see Supplementary Materials section.

Distinct developmental changes in regional gray matter volume and covariance in individuals with attention-deficit hyperactivity disorder: A longitudinal voxel-based morphometry study

BACKGROUND

Very few studies have investigated longitudinal clinical cohorts of attention-deficit/hyperactivity disorder (ADHD). Moreover, how baseline brain changes could affect the development of ADHD symptoms later in life remains elusive. Therefore, we aimed to fill this gap by exploring brain and clinical changes in youth with ADHD using a longitudinal design.

METHODS

This prospective study consisted of 74 children and adolescents with ADHD and 50 age-, sex-, intelligence-matched typically developing controls (TDC), evaluated at baseline (aged 7-19 years) and re-evaluated 5.3 years later (a mean follow-up latency). We applied voxel-based morphometry to characterize brain structures, followed by both mass-univariate and multivariate structural covariance statistics to identify brain regions with significant diagnosis-by-time interactions from late childhood/adolescence to early adulthood. We used the cross-lagged panel model to investigate the longitudinal association between structural brain metrics and core ADHD symptoms.

RESULTS

The mass-univariate statistic revealed significant diagnosis-by-time interactions in the right striatum and the sixth lobule of the cerebellum. This was expressed by increased striatal and decreased cerebellar volume in ADHD, while TDC showed inverse volume changes over time. The multivariate method showed significant diagnosis-by-time interactions in a structural covariance network consisting of the regions involved in the functional sensory-motor and default-mode networks. Higher baseline right striatal and cerebellar volumes were associated with elevated ADHD symptoms at follow-up.

CONCLUSIONS

Our findings suggest a temporal association between the divergent development of striatal and cerebellar regions and dynamical ADHD phenotypic expression through young adulthood. These results highlight a potential brain marker of future outcomes.

Differential associations of adolescent versus young adult cannabis initiation with longitudinal brain change and behavior

Leveraging ~10 years of prospective longitudinal data on 704 participants, we examined the effects of adolescent versus young adult cannabis initiation on MRI-assessed cortical thickness development and behavior. Data were obtained from the IMAGEN study conducted across eight European sites. We identified IMAGEN participants who reported being cannabis-naïve at baseline and had data available at baseline, 5-year, and 9-year follow-up visits. Cannabis use was assessed with the European School Survey Project on Alcohol and Drugs. T1-weighted MR images were processed through the CIVET pipeline. Cannabis initiation occurring during adolescence (14-19 years) and young adulthood (19-22 years) was associated with differing patterns of longitudinal cortical thickness change. Associations between adolescent cannabis initiation and cortical thickness change were observed primarily in dorso- and ventrolateral portions of the prefrontal cortex. In contrast, cannabis initiation occurring between 19 and 22 years of age was associated with thickness change in temporal and cortical midline areas. Follow-up analysis revealed that longitudinal brain change related to adolescent initiation persisted into young adulthood and partially mediated the association between adolescent cannabis use and past-month cocaine, ecstasy, and cannabis use at age 22. Extent of cannabis initiation during young adulthood (from 19 to 22 years) had an indirect effect on psychotic symptoms at age 22 through thickness change in temporal areas. Results suggest that developmental timing of cannabis exposure may have a marked effect on neuroanatomical correlates of cannabis use as well as associated behavioral sequelae. Critically, this work provides a foundation for neurodevelopmentally informed models of cannabis exposure in humans.

Patterns of brain dynamic functional connectivity are linked with attention-deficit/hyperactivity disorder-related behavioral and cognitive dimensions

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a clinically heterogeneous neurodevelopmental disorder defined by characteristic behavioral and cognitive features. Abnormal brain dynamic functional connectivity (dFC) has been associated with the disorder. The full spectrum of ADHD-related variation of brain dynamics and its association with behavioral and cognitive features remain to be established.

METHODS

We sought to identify patterns of brain dynamics linked to specific behavioral and cognitive dimensions using sparse canonical correlation analysis across a cohort of children with and without ADHD (122 children in total, 63 with ADHD). Then, using mediation analysis, we tested the hypothesis that cognitive deficits mediate the relationship between brain dynamics and ADHD-associated behaviors.

RESULTS

We identified four distinct patterns of dFC, each corresponding to a specific dimension of behavioral or cognitive function (r = 0.811-0.879). Specifically, the inattention/hyperactivity dimension was positively associated with dFC within the default mode network (DMN) and negatively associated with dFC between DMN and the sensorimotor network (SMN); the somatization dimension was positively associated with dFC within DMN and SMN; the inhibition and flexibility dimension and fluency and memory dimensions were both positively associated with dFC within DMN and between DMN and SMN, and negatively associated with dFC between DMN and the fronto-parietal network. Furthermore, we observed that cognitive functions of inhibition and flexibility mediated the relationship between brain dynamics and behavioral manifestations of inattention and hyperactivity.

CONCLUSIONS

These findings document the importance of distinct patterns of dynamic functional brain activity for different cardinal behavioral and cognitive features related to ADHD.

Neurodevelopmental risk and adaptation as a model for comorbidity among internalizing and externalizing disorders: genomics and cell-specific expression enriched morphometric study

BACKGROUND

Comorbidity is the rule rather than the exception for childhood and adolescent onset mental disorders, but we cannot predict its occurrence and do not know the neural mechanisms underlying comorbidity. We investigate if the effects of comorbid internalizing and externalizing disorders on anatomical differences represent a simple aggregate of the effects on each disorder and if these comorbidity-associated cortical surface differences relate to a distinct genetic underpinning.

METHODS

We studied the cortical surface area (SA) and thickness (CT) of 11,878 preadolescents (9-10 years) from the Adolescent Brain and Cognitive Development Study. Linear mixed models were implemented in comparative and association analyses among internalizing (dysthymia, major depressive disorder, disruptive mood dysregulation disorder, agoraphobia, panic disorder, specific phobia, separation anxiety disorder, social anxiety disorder, generalized anxiety disorder, post-traumatic stress disorder), externalizing (attention-deficit/hyperactivity disorder, oppositional defiant disorder, conduct disorder) diagnostic groups, a group with comorbidity of the two and a healthy control group. Genome-wide association analysis (GWAS) and cell type specificity analysis were performed on 4468 unrelated European participants from this cohort.

RESULTS

Smaller cortical surface area but higher thickness was noted across patient groups when compared to controls. Children with comorbid internalizing and externalizing disorders had more pronounced areal reduction than those without comorbidity, indicating an additive burden. In contrast, cortical thickness had a non-linear effect with comorbidity: the comorbid group had no significant CT differences, while those patient groups without comorbidity had significantly higher thickness compare to healthy controls. Distinct biological pathways were implicated in regional SA and CT differences. Specifically, CT differences were associated with immune-related processes implicating astrocytes and oligodendrocytes, while SA-related differences related mainly to inhibitory neurons.

CONCLUSION

The emergence of comorbidity across distinct clusters of psychopathology is unlikely to be due to a simple additive neurobiological effect alone. Distinct developmental risk moderated by immune-related adaptation processes, with unique genetic and cell-specific factors, may contribute to underlying SA and CT differences. Children with the highest risk but lowest resilience, both captured in their developmental morphometry, may develop a comorbid illness pattern.

Impact and centrality of attention dysregulation on cognition, anxiety, and low mood in adolescents

Functional impairments in cognition are frequently thought to be a feature of individuals with depression or anxiety. However, documented impairments are both broad and inconsistent, with little known about when they emerge, whether they are causes or effects of affective symptoms, or whether specific cognitive systems are implicated. Here, we show, in the adolescent ABCD cohort (N = 11,876), that attention dysregulation is a robust factor underlying wide-ranging cognitive task impairments seen in adolescents with moderate to severe anxiety or low mood. We stratified individuals high in DSM-oriented depression or anxiety symptomology, and low in attention deficit hyperactivity disorder (ADHD), as well as vice versa - demonstrating that those high in depression or anxiety dimensions but low in ADHD symptoms not only exhibited normal task performance across several commonly studied cognitive paradigms, but out-performed controls in several domains, as well as in those low in both dimensions. Similarly, we showed that there were no associations between psychopathological dimensions and performance on an extensive cognitive battery after controlling for attention dysregulation. Further, corroborating previous research, the co-occurrence of attention dysregulation was associated with a wide range of other adverse outcomes, psychopathological features, and executive functioning (EF) impairments. To assess how attention dysregulation relates to and generates diverse psychopathology, we performed confirmatory and exploratory network analysis with different analytic approaches using Gaussian Graphical Models and Directed Acyclic Graphs to examine interactions between ADHD, anxiety, low mood, oppositional defiant disorder (ODD), social relationships, and cognition. Confirmatory centrality analysis indicated that features of attention dysregulation were indeed central and robustly connected to a wide range of psychopathological traits across different categories, scales, and time points. Exploratory network analysis indicated potentially important bridging traits and socioenvironmental influences in the relationships between ADHD symptoms and mood/anxiety disorders. Trait perfectionism was uniquely associated with both better cognitive performance and broad psychopathological dimensions. This work suggests that attentional dysregulation may moderate the breadth of EF, fluid, and crystalized cognitive task outcomes seen in adolescents with anxiety and low mood, and may be central to disparate pathological features, and thus a target for attenuating wide-ranging negative developmental outcomes.

Conduct problems are associated with accelerated thinning of emotion-related cortical regions in a community-based sample of adolescents

Few studies have examined the association between conduct problems and cerebral cortical development. Herein, we characterize the association between age-related brain change and conduct problems in a large longitudinal, community-based sample of adolescents. 1,039 participants from the IMAGEN study possessed psychopathology and surface-based morphometric data at study baseline (M = 14.42 years, SD = 0.40; 559 females) and 5-year follow-up. Self-reports of conduct problems were obtained using the Strengths and Difficulties Questionnaire (SDQ). Vertex-level linear mixed effects models were implemented using the Matlab toolbox, SurfStat. To investigate the extent to which cortical thickness maturation was qualified by dimensional measures of conduct problems, we tested for an interaction between age and SDQ Conduct Problems (CP) score. There was no main effect of CP score on cortical thickness; however, a significant "Age by CP" interaction was revealed in bilateral insulae, left inferior frontal gyrus, left rostral anterior cingulate, left posterior cingulate, and bilateral inferior parietal cortices. Across regions, follow-up analysis revealed higher levels of CP were associated with accelerated age-related thinning. Findings were not meaningfully altered when controlling for alcohol use, co-occurring psychopathology, and socioeconomic status. Results may help to further elucidate neurodevelopmental patterns linking adolescent conduct problems with adverse adult outcomes.

Serotonin and Dopamine Blood Levels in ADHD-Like Dogs

As with humans, dogs can suffer from attention deficit hyperactivity disorder-like (ADHD-like) behaviors naturally and exhibit high levels of hyperactivity/impulsivity and attention deficit problems, making the domestic dog a potential animal model for ADHD. ADHD has a very complex pathophysiology in which many neurotransmitters are involved, such as serotonin and dopamine. The aim of the study was to evaluate serum serotonin and dopamine levels in dogs with ADHD-like symptomatology. Fifty-eight dogs were studied, of which, thirty-six were classified as ADHD-like after physical and behavioral assessments. Additionally, the dogs’ owners performed a series of scientifically validated questionnaires which included C-BARQ, the Dog Impulsivity Assessment Scale, and the Dog-ADHD rating scale. Serum from every animal was collected after the behavioral assessments and analyzed with commercial ELISA tests for serotonin and dopamine determination. Kruskal–Wallis tests and Lasso regressions were applied to assess the relationships between both neurotransmitters and the ADHD-like behaviors (as assessed by clinical evaluation and through the different questionnaires). The dogs clinically classified as ADHD-like showed lower serotonin and dopamine concentrations. Further, serotonin and dopamine levels were also linked to aggression, hyperactivity, and impulsivity. Decreased serotonin concentrations were also related to fear, attachment, and touch sensitivity. Finally, it must be noted that our data suggested a strong relationship between serotonin and dopamine and ADHD-like behaviors.

ADHD symptoms and diurnal cortisol in adolescents: The importance of comorbidities

BACKGROUND

Altered regulation of diurnal cortisol has been associated with both dimensional symptoms and clinical diagnoses of attention deficit-hyperactivity disorder (ADHD). Indeed, a recent meta-analysis suggests that lower diurnal cortisol output may be a biomarker of attention deficit-hyperactivity disorder (ADHD); importantly, however, the influence of psychiatric comorbidities on this association has not been characterized. Approximately two-thirds of children with ADHD have at least one co-occurring neuropsychiatric condition, and altered HPA-axis function has been implicated in many of these conditions. Using dimensional measures of psychopathology, we examined whether comorbid symptoms influence the association of ADHD symptoms with daily cortisol output.

METHODS

138 adolescents (ages 11-15 years) completed measures of symptoms of psychopathology and provided saliva samples over two days. We analyzed whether ADHD symptoms were related to morning, afternoon, and evening cortisol, the cortisol awakening response (CAR) and cumulative daily cortisol (area under the curve with respect to ground [AUCg]) while accounting for symptoms of three psychiatric disorders that are commonly comorbid with ADHD: conduct disorder (CD), anxiety, and depression. In sensitivity analyses, we included symptoms of oppositional defiant disorder (ODD) in place of CD symptoms.

FINDINGS

After controlling for symptoms of CD, anxiety, and depression, ADHD symptoms were associated significantly with higher cumulative diurnal cortisol (AUCg), morning cortisol, and afternoon cortisol. Symptoms of CD, anxiety and depression were not associated significantly with any cortisol metrics; however, in sensitivity analyses, ODD symptoms were associated with lower AUCg and morning cortisol.

DISCUSSION

Our findings highlight the distinct influence of ADHD and externalizing symptoms on cortisol output. Further work is needed to examine the specificity of altered HPA-axis activity as a biomarker of ADHD and to elucidate whether symptoms of ADHD differ in their association with diurnal cortisol as a function of their severity.

Multivariate associations between behavioural dimensions and white matter across children and adolescents with and without attention-deficit/hyperactivity disorder

BACKGROUND

Attention deficit/hyperactivity disorder (ADHD) is a heterogeneous neurodevelopmental disorder. Integrity of white matter microstructure plays a key role in the neural mechanism of ADHD presentations. However, the relationships between specific behavioural dimensions and white matter microstructure are less well known. This study aimed to identify associations between white matter and a broad set of clinical features across children and adolescent with and without ADHD using a data-driven multivariate approach.

METHOD

We recruited a total of 130 children (62 controls and 68 ADHD) and employed regularized generalized canonical correlation analysis to characterize the associations between white matter and a comprehensive set of clinical measures covering three domains, including symptom, cognition and behaviour. We further applied linear discriminant analysis to integrate these associations to explore potential developmental effects.

RESULTS

We delineated two brain-behaviour dimensional associations in each domain resulting a total of six multivariate patterns of white matter microstructural alterations linked to hyperactivity-impulsivity and mild affected; executive functions and working memory; externalizing behaviour and social withdrawal, respectively. Apart from executive function and externalizing behaviour sharing similar white matter patterns, all other dimensions linked to a specific pattern of white matter microstructural alterations. The multivariate dimensional association scores showed an overall increase and normalization with age in ADHD group while remained stable in controls.

CONCLUSIONS

We found multivariate neurobehavioral associations exist across ADHD and controls, which suggested that multiple white matter patterns underlie ADHD heterogeneity and provided neural bases for more precise diagnosis and individualized treatment.

Evidence from "big data" for the default-mode hypothesis of ADHD: a mega-analysis of multiple large samples

We sought to identify resting-state characteristics related to attention deficit/hyperactivity disorder, both as a categorical diagnosis and as a trait feature, using large-scale samples which were processed according to a standardized pipeline. In categorical analyses, we considered 1301 subjects with diagnosed ADHD, contrasted against 1301 unaffected controls (total N = 2602; 1710 males (65.72%); mean age = 10.86 years, sd = 2.05). Cases and controls were 1:1 nearest neighbor matched on in-scanner motion and key demographic variables and drawn from multiple large cohorts. Associations between ADHD-traits and resting-state connectivity were also assessed in a large multi-cohort sample (N = 10,113). ADHD diagnosis was associated with less anticorrelation between the default mode and salience/ventral attention (B = 0.009, t = 3.45, p-FDR = 0.004, d = 0.14, 95% CI = 0.004, 0.014), somatomotor (B = 0.008, t = 3.49, p-FDR = 0.004, d = 0.14, 95% CI = 0.004, 0.013), and dorsal attention networks (B = 0.01, t = 4.28, p-FDR < 0.001, d = 0.17, 95% CI = 0.006, 0.015). These results were robust to sensitivity analyses considering comorbid internalizing problems, externalizing problems and psychostimulant medication. Similar findings were observed when examining ADHD traits, with the largest effect size observed for connectivity between the default mode network and the dorsal attention network (B = 0.0006, t = 5.57, p-FDR < 0.001, partial-r = 0.06, 95% CI = 0.0004, 0.0008). We report significant ADHD-related differences in interactions between the default mode network and task-positive networks, in line with default mode interference models of ADHD. Effect sizes (Cohen's d and partial-r, estimated from the mega-analytic models) were small, indicating subtle group differences. The overlap between the affected brain networks in the clinical and general population samples supports the notion of brain phenotypes operating along an ADHD continuum.

Current opinions on the present and future use of functional near-infrared spectroscopy in psychiatry

Functional near-infrared spectroscopy (fNIRS) is an optical imaging technique for assessing human brain activity by noninvasively measuring the fluctuation of cerebral oxygenated- and deoxygenated-hemoglobin concentrations associated with neuronal activity. Owing to its superior mobility, low cost, and good tolerance for motion, the past few decades have witnessed a rapid increase in the research and clinical use of fNIRS in a variety of psychiatric disorders. In this perspective article, we first briefly summarize the state-of-the-art concerning fNIRS research in psychiatry. In particular, we highlight the diverse applications of fNIRS in psychiatric research, the advanced development of fNIRS instruments, and novel fNIRS study designs for exploring brain activity associated with psychiatric disorders. We then discuss some of the open challenges and share our perspectives on the future of fNIRS in psychiatric research and clinical practice. We conclude that fNIRS holds promise for becoming a useful tool in clinical psychiatric settings with respect to developing closed-loop systems and improving individualized treatments and diagnostics.

Neuroprotection in late life attention-deficit/hyperactivity disorder: A review of pharmacotherapy and phenotype across the lifespan

For decades, psychostimulants have been the gold standard pharmaceutical treatment for attention-deficit/hyperactivity disorder (ADHD). In the United States, an astounding 9% of all boys and 4% of girls will be prescribed stimulant drugs at some point during their childhood. Recent meta-analyses have revealed that individuals with ADHD have reduced brain volume loss later in life (>60 y.o.) compared to the normal aging brain, which suggests that either ADHD or its treatment may be neuroprotective. Crucially, these neuroprotective effects were significant in brain regions (e.g., hippocampus, amygdala) where severe volume loss is linked to cognitive impairment and Alzheimer's disease. Historically, the ADHD diagnosis and its pharmacotherapy came about nearly simultaneously, making it difficult to evaluate their effects in isolation. Certain evidence suggests that psychostimulants may normalize structural brain changes typically observed in the ADHD brain. If ADHD itself is neuroprotective, perhaps exercising the brain, then psychostimulants may not be recommended across the lifespan. Alternatively, if stimulant drugs are neuroprotective, then this class of medications may warrant further investigation for their therapeutic effects. Here, we take a bottom-up holistic approach to review the psychopharmacology of ADHD in the context of recent models of attention. We suggest that future studies are greatly needed to better appreciate the interactions amongst an ADHD diagnosis, stimulant treatment across the lifespan, and structure-function alterations in the aging brain.

Age-Related Variance in Performance versus Ratings of Attention and Impulse Regulation in Children: Implications for the Assessment of ADHD

Executive function task (EF) deficits are hypothesized to underlie difficulties with self-regulation. However, tasks assessing EF impairments have only been weakly correlated with rating scales that index self-regulation difficulties. A community sample of children and youth aged between 8 and 20 years old were assessed longitudinally. Growth curve analyses and correlations were conducted to better understand how these two types of measures relate to one another across development, as well as the impact of age-related variance. EF was assessed using the Stroop Task and Trail Making test and behavioral ratings of self-regulation were captured using the SWAN scale. EF task performance improved steeply until age 14–15, whereas the SWAN Scale showed small age-related decreases. EF task performance was moderately correlated with age among 8–13-year-olds and to a lesser extent among 14–20-year-olds. SWAN scores were not significantly related to age in either group. Correlations were similar in an ADHD “at-risk” subgroup. EF task performance and parent ratings of attention regulation have different developmental trajectories, which may partly explain why correlations are low to modest in these samples. In particular, age-related variance is an important methodological consideration with significant implications for the assessment of self-regulation in children and youth with ADHD.

Bayesian causal network modeling suggests adolescent cannabis use accelerates prefrontal cortical thinning

While there is substantial evidence that cannabis use is associated with differences in human brain development, most of this evidence is correlational in nature. Bayesian causal network (BCN) modeling attempts to identify probable causal relationships in correlational data using conditional probabilities to estimate directional associations between a set of interrelated variables. In this study, we employed BCN modeling in 637 adolescents from the IMAGEN study who were cannabis naïve at age 14 to provide evidence that the accelerated prefrontal cortical thinning found previously in adolescent cannabis users by Albaugh et al. [1] is a result of cannabis use causally affecting neurodevelopment. BCNs incorporated data on cannabis use, prefrontal cortical thickness, and other factors related to both brain development and cannabis use, including demographics, psychopathology, childhood adversity, and other substance use. All BCN algorithms strongly suggested a directional relationship from adolescent cannabis use to accelerated cortical thinning. While BCN modeling alone does not prove a causal relationship, these results are consistent with a body of animal and human research suggesting that adolescent cannabis use adversely affects brain development.

RDoC and the developmental origins of psychiatric disorders: How did we get here and where are we going?

About a decade ago, the National Institute of Mental Health (NIMH) proposed an innovative framework, the Research Domain Criteria (RDoC), to classify psychiatric disorders. This complementary approach has been used with existing diagnostic systems to identify transdiagnostic factors that inform early detection of mental health disturbances and critically, provide novel targets for interventions. An additional goal, however, has been to clarify developmental processes and illness trajectories by operationalizing dimensional constructs during sensitive periods of neurofunctional development to capture the early emergence of behavioral alterations and impairment. As developmental factors are inherent to all RDoC systems and the units of analysis therein, NIMH shepherded developmental-oriented research with targeted funding opportunity announcements. This resulting work has highlighted promising phenotypes and biological markers related to psychiatric illness across the lifespan.

Inattentive and hyperactive traits differentially associate with inter-individual functional synchrony during video viewing in young children without ADHD

Inattention and hyperactivity present on a spectrum and may influence the way children perceive and interact with the world. We investigated whether normative variation in inattentive and hyperactive traits was associated with differences in brain function, while children watched clips from an age-appropriate television program. Functional magnetic resonance imaging (fMRI) data and parent reports of inattention and hyperactivity traits were collected from 81 children 4–7 years of age with no parent-reported diagnoses. Data were analyzed using intersubject correlations (ISCs) in mixed effects models to determine if inattentive and hyperactive traits were associated with idiosyncrasy of fMRI response to the video. We hypothesized that pairs of children with higher average inattention and hyperactivity scores would show less interindividual brain synchrony to one another than pairs with lower average scores on these traits. Video watching engaged widespread visual, auditory, default mode and dorsal prefrontal regions. Inattention and hyperactivity were separably associated with ISC in many of these regions. Our findings suggest that the spectrum of inattention and hyperactivity traits in children without ADHD are differentially associated with neural processing of naturalistic video stimuli, which may have implications for understanding how children with different levels of these traits process audiovisual information in unconstrained conditions.

An examination of the relationships between attention/deficit hyperactivity disorder symptoms and functional connectivity over time

Previous cross-sectional work has demonstrated resting-state connectivity abnormalities in children and adolescents with attention/deficit hyperactivity disorder (ADHD) relative to typically developing controls. However, it is unclear to what extent these neural abnormalities confer risk for later symptoms of the disorder, or represent the downstream effects of symptoms on functional connectivity. Here, we studied 167 children and adolescents (mean age at baseline = 10.74 years (SD = 2.54); mean age at follow-up = 13.3 years (SD = 2.48); 56 females) with varying levels of ADHD symptoms, all of whom underwent resting-state functional magnetic resonance imaging and ADHD symptom assessments on two occasions during development. Resting-state functional connectivity was quantified using eigenvector centrality mapping. Using voxelwise cross-lag modeling, we found that less connectivity at baseline within right inferior frontal gyrus was associated with more follow-up symptoms of inattention (significant at an uncorrected cluster-forming threshold of p ≤ 0.001 and a cluster-level familywise error corrected threshold of p < 0.05). Findings suggest that previously reported cross-sectional abnormalities in functional connectivity within inferior frontal gyrus in patients with ADHD may represent a longitudinal risk factor for the disorder, in line with efforts to target this region with novel therapeutic methods.

Reciprocal Developmental Relations Between ADHD and Anxiety in Adolescence: A Within-Person Longitudinal Analysis of Commonly Co-Occurring Symptoms

Objective: Significant anxiety often occurs in the presence of ADHD symptoms; however, the reasons are not well understood. We aimed to establish whether the relations between ADHD symptons and anxiety are bidirectional or unidirectional.

METHOD

Weexamined the developmental relations between ADHD and anxiety symptoms across adolescence (ages 13, 15, and 17) in a community-ascertained, normative longitudinal sample of 1,483 youth (52% male). We used an autoregressive latent trajectory model with structured residuals (ALT-SR) to examine within-person developmental relations between ADHD and anxiety symptoms to determine whether it is ADHD symptoms that lead to anxiety symptoms and/or the reverse.

RESULTS

Results suggested that there are reciprocal within-person developmental relations between ADHD and anxiety symptoms.

CONCLUSIONS

Our findings support the recommendation that targeting ADHD symptoms can be fruitful for addressing anxiety symptoms; however, they suggest that targeting anxiety symptoms may also benefit ADHD symptoms. Results also underline the importance of careful assessment for underlying ADHD symptoms among adolescents presenting with anxiety.

Consortium neuroscience of attention deficit/hyperactivity disorder and autism spectrum disorder: The ENIGMA adventure

Neuroimaging has been extensively used to study brain structure and function in individuals with attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) over the past decades. Two of the main shortcomings of the neuroimaging literature of these disorders are the small sample sizes employed and the heterogeneity of methods used. In 2013 and 2014, the ENIGMA-ADHD and ENIGMA-ASD working groups were respectively, founded with a common goal to address these limitations. Here, we provide a narrative review of the thus far completed and still ongoing projects of these working groups. Due to an implicitly hierarchical psychiatric diagnostic classification system, the fields of ADHD and ASD have developed largely in isolation, despite the considerable overlap in the occurrence of the disorders. The collaboration between the ENIGMA-ADHD and -ASD working groups seeks to bring the neuroimaging efforts of the two disorders closer together. The outcomes of case-control studies of subcortical and cortical structures showed that subcortical volumes are similarly affected in ASD and ADHD, albeit with small effect sizes. Cortical analyses identified unique differences in each disorder, but also considerable overlap between the two, specifically in cortical thickness. Ongoing work is examining alternative research questions, such as brain laterality, prediction of case-control status, and anatomical heterogeneity. In brief, great strides have been made toward fulfilling the aims of the ENIGMA collaborations, while new ideas and follow-up analyses continue that include more imaging modalities (diffusion MRI and resting-state functional MRI), collaborations with other large databases, and samples with dual diagnoses.

Socio-demographic and clinical correlates of parenting style among parents having ADHD children: a cross-section study

Background

ADHD affects 7.8% of the school-aged population, making it one of the most common childhood brain illnesses. It is characterized by abnormally high levels of inattention, activity, and impulsivity at a young age. Being a parent of a child with ADHD is a real challenge, as the parents tend to be more disapproving, critical, and provide more impulse control directions; such parenting style can have an impact on the illnesses course, accentuate its signs and symptoms, and lead to secondary development of co-morbid psychiatric and behavioral problems. This makes the parent-child effect a matter of clinical importance that needs to be carefully assessed and managed. We aimed to estimate the sociodemographic and clinical correlates of parenting attitudes among parents having ADHD children. This cross-sectional study included 48 ADHD children from both sexes, aged from 6 to 12 years old, and their parents. In our study, we applied the Stanford-Binet Intelligence Scale 5th edition, the Conner’s Parent Rating Scale-revised, the parenting style as perceived by children questionnaire, and the Fahmy and El-Sherbini questionnaire for the measurement of socioeconomic status.

Results

Mothers of ADHD children had significantly lower scores of over-protections parenting style than the fathers; the current study showed a significant increase in total parenting scores and warmth/support in mild ADHD cases than in moderate and severe ones, and there is a significant increase in the mother’s positive parenting style toward ADHD children with lower levels of social problems, mild cases, and older age. There is a significant increase of positive parenting style toward ADHD children exerted by post graduated, professionally working, and high social class fathers and by working mothers among rural residents and high social class mothers. There is a positive correlation between IQ and a mother’s warmth/support.

Conclusion

ADHD children with mild symptoms, higher social functioning of the child, high socioeconomic level of the family, better education, and professional occupations of parents were associated with positive parenting style.

Assessment of Optical Coherence Tomography Findings in Adults with Attention Deficit Hyperactivity Disorder: A Case-Control Study

Background

To assess retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness using optical coherence tomography in attention deficit hyperactivity disorder adults on regular methylphenidate treatment, comparing them to healthy controls.

Methods

A total of 33 attention deficit hyperactivity disorder adults and 31 healthy subjects, matched for age, gender, and education (control group), were included in this study. Retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness of both eyes were measured using optical coherence tomography, and symptom severity was evaluated using Adult Attention Deficit Hyperactivity Disorder Self-Report Scale and Wender Utah Rating Scale.

Results

There was no significant difference in retinal nerve fiber layer thickness between the attention deficit hyperactivity disorder and control groups (P > .05). Thinner ganglion cell-inner plexiform layer total (P = .044), inferior (P = .012), and inferior nasal quadrant thickness (P = .049) were observed in attention deficit hyperactivity disorder patients as compared to the controls.

Conclusion

Findings detected thinner ganglion cell-inner plexiform layer in some quadrants of attention deficit hyperactivity disorder adults, indicating an early disorder in retinal structure development. Whether retinal structures are sensitive attention deficit hyperactivity disorder biomarkers should be supported and investigated in future multimodal studies.

The structural connectome in ADHD

Attention-deficit/hyperactivity disorder (ADHD) has been conceptualized as a brain dysconnectivity disorder. In the past decade, noninvasive diffusion magnetic resonance imaging (dMRI) studies have demonstrated that individuals with ADHD have alterations in the white matter structural connectome, and that these alterations are associated with core symptoms and cognitive deficits in patients. This review aims to summarize recent dMRI-based structural connectome studies in ADHD from voxel-, tractography-, and network-based perspectives. Voxel- and tractography-based studies have demonstrated disrupted microstructural properties predominantly located in the frontostriatal tracts, the corpus callosum, the corticospinal tracts, and the cingulum bundle in patients with ADHD. Network-based studies have suggested abnormal global and local efficiency as well as nodal properties in the prefrontal and parietal regions in the ADHD structural connectomes. The altered structural connectomes in those with ADHD provide significant signatures for prediction of symptoms and diagnostic classification. These studies suggest that abnormalities in the structural connectome may be one of the neural underpinnings of ADHD psychopathology and show potential for establishing imaging biomarkers in clinical evaluation. However, given that there are inconsistent findings across studies due to sample heterogeneity and analysis method variations, these ADHD-related white matter alterations are still far from informing clinical practice. Future studies with larger and more homogeneous samples are needed to validate the consistency of current results; advanced dMRI techniques can help to generate much more precise estimation of white matter pathways and assure specific fiber configurations; and finally, dimensional analysis frameworks can deepen our understanding of the neurobiology underlying ADHD.

The Differential Effect of Anxiety and ADHD Symptoms on Inhibitory Control and Sustained Attention for Threat Stimuli: A Go/No-Go Eye-Movement Study

Objective: This study examined the synergistic effects of ADHD and anxiety symptoms on attention and inhibitory control depending on the emotional content of the stimuli. Method: Fifty-four typically developing individuals (27 children/adolescents and 27 adults) completed an eye-movement based emotional Go/No-Go task, using centrally presented (happy, angry) faces and neutral/symbolic stimuli. Sustained attention was measured through saccade latencies and saccadic omission errors (Go trials), and inhibitory control through saccadic commission errors (No-Go trials). ADHD and anxiety were assessed dimensionally. Results: Elevated ADHD symptoms were associated with more commission errors and slower saccade latencies for angry (vs. happy) faces. In contrast, angry faces were linked to faster saccade onsets when anxiety symptoms were high, and this effect prevailed when both anxiety and ADHD symptoms were high. Conclusion: Social threat impacted performance in individuals with sub-clinical anxiety and ADHD differently. The effects of anxiety on threat processing prevailed when both symptoms were high.

Functional abnormality in the sensorimotor system attributed to NRXN1 variants in boys with attention deficit hyperactivity disorder

Impaired sensorimotor circuits have been suggested in Attention-deficit/hyperactivity disorder (ADHD). NRXN1, highly expressed in cortex and cerebellum, was one of the candidate risk genes for ADHD, while its effects on sensorimotor circuits are unclear. In this content, we aimed to investigate the differential brain effects as functions of the cumulative genetic effects of NRXN1 variants in ADHD and healthy controls (HCs), identifying a potential pathway mapping from NRXN1, sensorimotor circuits, to ADHD. Magnetic resonance imaging, blood samples and clinical assessments were acquired from 53 male ADHD and 46 sex-matched HCs simultaneously. The effects of the cumulative genetic effects of NRXN1 variants valued by poly-variant risk score (PRS), on brain function was measured by resting-state functional connectivity (rs-FC) of cerebrocerebellar circuits. Mediation analyses were conducted to evaluate the association between NRXN1, functional abnormality, and ADHD diagnosis, as well as ADHD symptoms. The results were validated by bootstrapping and 10,000 times permutation tests. The rs-FC analyses demonstrated significant mediation models for ADHD diagnosis, and emphasized the involvement of cerebellum, middle cingulate gyrus and temporal gyrus, which are crucial parts of sensorimotor circuits. The current study suggested NRXN1 conferred risk for ADHD by regulating the function of sensorimotor circuits.

The Limits of Motivational Influence in ADHD: No Evidence for an Altered Reaction to Negative Reinforcement

Functional magnetic resonance imaging studies have reported a diminished response in the brain’s reward circuits to contingent cues predicting future monetary gain in adolescents with attention-deficit/hyperactivity disorder (ADHD). The situation with regard to monetary loss is less clear, despite recognition that both positive and negative consequences impact ADHD behaviour. Here, we employ a new Escape Monetary Loss Incentive task in an MRI scanner, which allows the differentiation of contingency and valence effects during loss avoidance, to examine ADHD-related alterations in monetary loss processing. There was no evidence of atypical processing of contingent or non-contingent monetary loss cues in ADHD — either in terms of ratings of emotional and motivational significance or brain responses. This suggests that the ability to process contingencies between performance and negative outcomes is intact in ADHD and that individuals with ADHD are no more (or less) sensitive to negative outcomes than controls. This latter finding stands in stark contrast to recent evidence from a similar task of atypical emotion network recruitment (e.g. amygdala) in ADHD individuals to cues predicting another negative event, the imposition of delay, suggesting marked specificity in the way they respond to negative events.

Altered Variability and Concordance of Dynamic Resting-State fMRI Indices in Patients With Attention Deficit Hyperactivity Disorder

Objective: Attention deficit hyperactivity disorder (ADHD) is a commonly diagnosed neuropsychiatric disorder in children, which is characterized by inattention, hyperactivity and impulsivity. Using resting-state functional magnetic resonance imaging (R-fMRI), the alterations of static and dynamic characteristics of intrinsic brain activity have been identified in patients with ADHD. Yet, it remains unclear whether the concordance among indices of dynamic R-fMRI is altered in ADHD. Methods: R-fMRI scans obtained from 50 patients with ADHD and 28 healthy controls (HC) were used for the current study. We calculated the regional dynamic changes in brain activity indices using the sliding-window method and compared the differences in variability of these indices between ADHD patients and HCs. Further, the concordance among these dynamic indices was calculated and compared. Finally, the relationship between variability/concordance of these indices and ADHD-relevant clinical test scores was investigated. Results: Patients with ADHD showed decreased variability of dynamic amplitude of low-frequency fluctuation (dALFF) in the left middle frontal gyrus and increased one in right middle occipital gyrus, as compared with the HCs. Besides, ADHD patients showed decreased voxel-wise concordance in the left middle frontal gyrus. Further, lower voxel-wise concordance in ADHD's left middle frontal gyrus was associated with more non-perseverative errors in Wisconsin Card Sorting Test, which reflects worse cognitive control. Conclusion: Our findings suggest that variability and concordance in dynamic brain activity may serve as biomarkers for the diagnosis of ADHD. Further, the decreased voxel-wise concordance is associated with deficit in cognitive control in ADHD patients.