Trait Mechanisms in Youth with and without Attention-Deficit/Hyperactivity Disorder

Construction of Meta-Thinking Educational Program Based on Mental-Brain Simulation (MTMBS) and Evaluating its Effectiveness on Executive Functions, Emotion Regulation, and Impulsivity in Children With ADHD: A Resting-State Functional MRI Study

OBJECTIVE

The aim of present research was to make a Meta-Thinking educational program based on mental-brain simulation and to evaluate its effectiveness on executive functions, emotion regulation and impulsivity in children with ADHD.

METHODS

The research method was Embedded Design: Embedded Experimental Model. The research sample included 32 children with ADHD who were randomly assigned to two experimental and control groups. The intervention was implemented for eight sessions of 1.5 hr for the experimental group, and fMRI images were taken from them, while the control group didn't receive any treatment. Finally, using semi-structured interviews, coherent information was collected from the parents of the experimental group about the changes made. Data were analyzed with SPSS-24, MAXQDA, fMRIprep, and FSL software.

RESULTS

The Meta-Thinking Educational Program had effect on performance of ADHD children and suppressed brain regions related to DMN.

CONCLUSION

The Implementation of this educational program plays a vital role in improving psychological problems of children with ADHD.

Mental health in Canadian children and adolescents during COVID-19 pandemic: the role of personality and, coping and stress responses

In December 2019, the Coronavirus Disease (COVID-19) pandemic first emerged in China and quickly spread to other countries. Previous studies have shown that the COVID-19 pandemic and the consequences have negatively impacted the mental health of adults. Individual differences such as personality could contribute to mental health. Furthermore, coping and responses to stress may affect an individual's response to the pandemic. In the past, studies have only investigated this relationship in adults. In the current study, we examine how personality traits (using the Five-Factor Model as our framework) and Coping and Response to COVID-19 stress are related to the mental health of Canadian children and adolescents during the pandemic. Using parent reports of 100 preschoolers and 607 6-18-year-old children, we performed multiple regression analysis to explore how personality traits predict the effects of COVID-19 on mental health. The results showed that personality traits are associated with the mental health of Canadian youth during the COVID-19 pandemic. In preschoolers, Neuroticism and Agreeableness predicted the most mental health problems, and in 6-18-year-old children, Extraversion negatively predicted the most mental health problems. Also, Openness to Experience was the weakest predictor of mental health status in Canadian youth. These findings could be useful in understanding children's responses to the COVID-19 pandemic and could assist public health services delivering mental health services specifically tailored to children's personalities during and after this pandemic.

Individual Differences in Germ Spreading Behaviors Among Children With Attention-Deficit/Hyperactivity Disorder: The Role of Executive Functioning

OBJECTIVE

Infectious diseases, such as coronavirus disease 2019 (COVID-19), are commonly transmitted by respiratory droplets and contact with contaminated surfaces. Individuals with attention-deficit/hyperactivity disorder (ADHD) are more likely to be infected with COVID-19 and experience more hospitalizations than individuals without ADHD. The current study investigated the role of ADHD symptomatology and executive functioning (EF) in germ spreading behavior frequency among young children with and without ADHD and parenting responses to these behaviors.

METHODS

Participants included 53 children diagnosed with ADHD and 47 typically developing (TD) children between the ages of 4-5 years (76% male; Mage = 4.62; 86% Hispanic/Latinx). Parents and teachers reported on children's ADHD symptomatology and children completed three EF tasks. Germ spreading behavior frequency (direct contact of hand to face and toy in mouth) and parenting responses (verbal and nonverbal behaviors) were observed during a 5-min parent-child play situation.

RESULTS

Negative binomial regression analyses indicated that both ADHD diagnostic status and poor metacognition predicted both higher rates of toy to mouth (β = 1.94, p < .001; β = 0.03, p = .004) and face touching frequency (β = 0.60, p = .03; β = 0.03, p = .004), respectively. Additionally, poor attention and worse cognitive flexibility only predicted higher rates of toy to mouth frequency (β = 0.09, p < .001; β = -0.04, p = .001), respectively.

CONCLUSIONS

Young children with ADHD are at high risk for spreading germs via putting toys in their mouth and touching their face. Particularly, high levels of inattention and poor EF appear to be associated with higher rates of germ spreading behaviors.

Shared genetics between autism spectrum disorder and attention-deficit/hyperactivity disorder and their association with extraversion

BACKGROUND

Deciphering the genetic relationships between autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) may uncover underlining shared pathophysiology as well as inform treatment.

METHODS

The summary results of genome-wide association studies on ADHD, ASD, and extraversion were utilized for the analyzes. Genetic correlations between ADHD, ASD, and extraversion were tested using linkage disequilibrium score regression. Causal relationships between ADHD, ASD, and extraversion were investigated using Mendelian randomization (MR) analysis. Novel pleiotropic genomic loci shared by ADHD and ASD were identified using a cross-trait meta-analysis.

RESULTS

Extraversion was positively correlated with ADHD (r_g = 0.205) and negatively correlated with ASD (r_g = -0.193). The MR analysis showed that ADHD confers a causal effect on ASD (OR: 1.35, 95% confidence interval (CI):1.20-1.52) and vice versa (1.46, 1.38-1.55). Extraversion exerts a causal effect on ADHD only (1.19, 1.05-1.33). The cross-trait meta-analysis identified three novel pleiotropic genomic loci for ADHD and ASD, involving two pleiotropic genes, LINC00461 and KIZ.

CONCLUSIONS

Our study provides new insights into the shared genetics of ADHD and ASD and their connections with extraversion.

The interaction between infant negative emotionality and cognition predicts ADHD-related behaviors in toddlerhood

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent disorder commonly identified in childhood. Affective and cognitive characteristics that are identifiable as early as infancy could be signals of risk for developing ADHD. Specifically, the interplay between emotionality and cognition may be important in predicting early symptoms of ADHD. This study examined the independent and interactive effects of infant negative emotionality and cognition on the development of inattention and hyperactivity/impulsivity in toddlerhood among infants at high and low familial likelihood for ADHD. Participants were 64 infants (M = 8.7, SD = 1.8) at high (n = 32) and low (n = 32) familial likelihood for ADHD, defined as at least one parent with ADHD or two parents without ADHD, respectively. Negative emotionality and cognition in infancy were assessed using the Infant Behavior Questionnaire and the Bayley's Scales of Infant and Toddler Development, and ADHD symptoms were assessed at toddler follow-up (M= 20.0, SD= 3.2) using the Child Behavior Checklist. Accounting for the quality of parent-child interaction, infants' negative emotionality (β = .033, p = .938) and cognition (β = .006, p = .884) did not independently predict toddlers' ADHD-related behaviors, but their interaction did (β = .110, p = .019). For infants with higher levels of cognition (>95th percentile), higher negative emotionality predicted more ADHD-related behaviorss. For infants with lower levels of cognition (<11th percentile), higher negative emotionality predicted fewer ADHD-related behaviors. There may be two affective-cognitive pathways to inattention and hyperactivity/impulsivity in toddlerhood. The combination of higher levels of negative emotionality and cognition may result in greater frustration when goals are blocked, resulting in the expression of dysregulated behaviors (i.e., ADHD symptoms). Alternatively, low levels of negative emotionality and cognition combined may lead to dysregulation that is primarily cognitive in nature (such as the inattention symptoms of ADHD). Investigating affective and cognitive processes simultaneously may be important for increasing understanding of the early signals of ADHD risk.

Mendelian randomization analysis for attention deficit/hyperactivity disorder: studying a broad range of exposures and outcomes

BACKGROUND

Attention deficit/hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder caused by a combination of genetic and environmental factors and is often thought as an entry point into a negative life trajectory, including risk for comorbid disorders, poor educational achievement or low income. In the present study, we aimed to clarify the causal relationship between ADHD and a comprehensive range of related traits.

METHODS

We used genome-wide association study (GWAS) summary statistics for ADHD (n = 53 293) and 124 traits related to anthropometry, cognitive function and intelligence, early life exposures, education and employment, lifestyle and environment, longevity, neurological, and psychiatric and mental health or personality and psychosocial factors available in the MR-Base database (16 067 ≤n ≤766 345). To investigate their causal relationship with ADHD, we used two-sample Mendelian randomization (MR) with a range of sensitivity analyses, and validated MR findings using causal analysis using summary effect estimates (CAUSE), aiming to avoid potential false-positive results.

RESULTS

Our findings strengthen previous evidence of a causal effect of ADHD liability on smoking and major depression, and are consistent with a causal effect on odds of decreased average total household income [odds ratio (OR) = 0.966, 95% credible interval (CrI) = (0.954, 0.979)] and increased lifetime number of sexual partners [OR = 1.023, 95% CrI = (1.013, 1.033)]. We also found evidence for a causal effect on ADHD for liability of arm predicted mass and weight [OR = 1.452, 95% CrI = (1.307, 1.614) and OR = 1.430, 95% CrI = (1.326, 1.539), respectively] and time spent watching television [OR = 1.862, 95% CrI = (1.545, 2.246)], and evidence for a bidirectional effect for age of first sexual intercourse [beta = -0.058, 95% CrI = (-0.072, -0.044) and OR = 0.413, 95% CrI = (0.372, 0.457), respectively], odds of decreased age completed full-time education [OR = 0.972, 95% CrI = (0.962, 0.981) and OR = 0.435, 95% CrI = (0.356, 0.533), respectively] and years of schooling [beta = -0.036, 95% CrI = (-0.048, -0.024) and OR = 0.458, 95% CrI = (0.411, 0.511), respectively].

CONCLUSIONS

Our results may contribute to explain part of the widespread co-occurring traits and comorbid disorders across the lifespan of individuals with ADHD and may open new opportunities for developing preventive strategies for ADHD and for negative ADHD trajectories.

Temperament Dimensions and Awakening Cortisol Levels in Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To investigate whether temperament dimensions, Effortful Control (EC), Surgency-Extraversion (SE), and Negative Affectivity (NA), are associated with attention-deficit/hyperactivity disorder (ADHD) and how they relate to awakening cortisol levels, as a proxy measure of peripheral arousal.

METHODS

Parent-rated temperament and saliva samples were collected from 55 children with ADHD and 65 age-matched controls.

RESULTS

Compared to controls, youths with ADHD showed lower EC, higher NA, and lower awakening cortisol levels but did not differ in SE. Similar findings emerged in dimensional analyses linking temperament traits to inattention and hyperactivity-impulsivity symptoms. The results remained unchanged when controlling for the presence of co-occurring opposition-defiance and anxiety traits, as well as medication status. Temperament dimensions were not associated with cortisol levels.

CONCLUSIONS

Poor temperamental emotional and cognitive self-regulation showed significant associations with ADHD but did not appear to be linked to the under-arousal typically seen in ADHD.

Differentiating Symptoms of ADHD in Preschoolers: The Role of Emotion Regulation and Executive Function

Objective: This study examined the extent to which individual differences in executive function (EF) and emotion regulation (ER) were uniquely associated with inattention and hyperactivity symptoms of ADHD, respectively. Method: Participants included 249 preschool children with at-risk or clinically elevated levels of externalizing behavior problems (EBPs). Results: Regression analyses were conducted examining the association between EF and ER-as reported by parents/teachers and assessed via child task performance-and hyperactivity and inattention. Even after accounting for IQ, age, sex, and severity of oppositional defiant disorder, greater levels of parent/teacher-reported EF problems and worse EF performance were associated with greater inattention. In addition, better observed ER was associated with lower inattention. Conversely, greater levels of parent/teacher-reported EF problems and worse parent/teacher-reported ER were associated with greater hyperactivity. Conclusion: Our findings suggest that underlying deficits in EF and ER do differentially relate to ADHD symptoms.

The amygdala in adolescents with attention-deficit/hyperactivity disorder: Structural and functional correlates of delay aversion

OBJECTIVES

Recent magnetic resonance imaging (MRI) studies implicate structural alterations of amygdala, a brain region responsible for processing and experiencing negative emotions, in adolescents with attention-deficit/hyperactivity disorder (ADHD). Here we examined ADHD-related structural correlates of amygdala functional activity elicited during a functional MRI task designed to test behavioural and brain responses to the imposition of delay - an event known to both elicit amygdala hyperactivation and aversity in ADHD.

METHODS

Structural MRI scans from 28 right-handed male adolescents with combined type ADHD and 32 age-matched controls were analysed. Regional grey matter volumes of ADHD and control participants (P[FWE] < 0.05) were correlated with delay aversion self-ratings and neural activity in response to delay-related cues on the Escape Delay Incentive fMRI task.

RESULTS

ADHD was associated with significantly reduced volumes in bilateral amygdala, parahippocampal and temporal gyrus (P[FWE] < 0.05), greater basolateral amygdala activation to delay-related cues (P[FWE] < 0.05) and higher delay aversion self-ratings. Amygdala volume reductions were significantly correlated with, and statistically mediated the pathway from ADHD to, delay-cue-related amygdala hyperactivity (P < 0.01) and self-reported delay aversion (P < 0.01).

CONCLUSIONS

We provide the first evidence of the functional significance of reduced amygdala volumes in adolescents with ADHD by highlighting its relation to delay-induced brain activity that is linked to delay aversion.

Toward a Revised Nosology for Attention-Deficit/Hyperactivity Disorder Heterogeneity

Attention-deficit/hyperactivity disorder (ADHD) is among the many syndromes in the psychiatric nosology for which etiological signal and clinical prediction are weak. Reducing phenotypic and mechanistic heterogeneity should be useful to arrive at stronger etiological and clinical prediction signals. We discuss key conceptual and methodological issues, highlighting the role of dimensional features aligned with Research Domain Criteria and cognitive, personality, and temperament theory as well as neurobiology. We describe several avenues of work in this area, utilizing different statistical, computational, and machine learning approaches to resolve heterogeneity in ADHD. We offer methodological and conceptual recommendations. Methodologically, we propose that an integrated approach utilizing theory and advanced computational logic to address targeted questions, with consideration of developmental context, can render the heterogeneity problem tractable for ADHD. Conceptually, we conclude that the field is on the cusp of justifying an emotionally dysregulated subprofile in ADHD that may be useful for clinical prediction and treatment testing. Cognitive profiles, while more nascent, may be useful for clinical prediction and treatment assignment in different ways depending on developmental stage. Targeting these psychological profiles for neurobiological and etiological study to capture different pathophysiological routes remains a near-term opportunity. Subtypes are likely to be multifactorial, cut across multiple dimensions, and depend on the research or clinical outcomes of interest for their ultimate selection. In this context parallel profiles based on cognition, emotion, and specific neural signatures appear to be on the horizon, each with somewhat different utilities. Efforts to integrate such cross-cutting profiles within a conceptual dysregulation framework are well underway.

Heterogeneity and Subtyping in Attention-Deficit/Hyperactivity Disorder-Considerations for Emerging Research Using Person-Centered Computational Approaches

Few if any experts believe that existing psychiatric diagnostic categories included in DSM and ICD are actually discrete disease entities. Attention-deficit/hyperactivity disorder (ADHD) is emblematic of the problems in the existing psychiatric classification system. ADHD symptoms reliably cluster into two correlated dimensions in factor analysis. However, children with ADHD vary considerably in their symptom profiles, symptom trajectories, clinical outcomes, and biological and psychological correlates. Thus, the field has sought alternative approaches that harness the dimensions of emotional, cognitive, and behavioral functioning that underlie ADHD and other existing psychiatric categories to create informative phenotypes that improve clinical prediction and clarify etiology. Within ADHD, cognitive (neuropsychological) and temperament/personality features have received considerable attention. In some cases, subphenotypes based on these features appear to improve on existing classifications and could eventually be translated into clinical practice. This review summarizes findings from subphenotyping efforts in ADHD that use cognitive, emotion-related, and other features to highlight major considerations for research applying person-oriented approaches to inform an improved psychiatric nosology. Considerations related to feature selection, validation of newly proposed divisions, defining populations of interest, and incorporating a developmental perspective are discussed.

Executive functions, Personality traits and ADHD symptoms in adolescents: A mediation analysis

Certain personality traits and cognitive domains of executive functions (EF) are differentially related to attention deficit hyperactivity disorder (ADHD) symptoms in adolescents. This study aimed to analyze the five-factor model (FFM) personality characteristics in adolescents with ADHD, and to examine whether EF mediate the relationships between FFM personality traits and ADHD symptoms. A comprehensive diagnostic assessment, including ADHD clinical interviews, ADHD rating scales, neuropsychological EF testing (i.e., working memory, flexibility and inhibition) and a personality assessment was carried out in a sample of 118 adolescents (75 ADHD and 43 control participants, 68% males), aged 12 to 16 years, and their parents and teachers. Adolescents with ADHD had lower scores than control participants on Conscientiousness and Agreeableness, and higher scores on Neuroticism. Structural equation models (SEM) showed that Conscientiousness directly influenced inattentive and hyperactive-impulsive symptoms, while Neuroticism, Agreeableness, and Extraversion directly affected hyperactive-impulsive symptoms. Only Conscientiousness exerted indirect effects on inattention, but not on hyperactivity-impulsivity symptoms, via EF; higher scores on Conscientiousness were related to higher scores on EF, which in turn were related to lower scores on inattentive symptoms. These findings corroborate the relationships between ADHD symptoms, FFM personality traits and EF and indicate the mediating effect of EF on the relationship between Conscientiousness and inattention.

Impact of personality on adherence to and beliefs about ADHD medication, and perceptions of ADHD in adolescents

BACKGROUND

Adherence to attention deficit hyperactivity disorder (ADHD) medication can prevent serious consequences, possibly with lifelong effects. Numerous factors have been observed that influence adherent behaviour, but the impact of personality traits has been inadequately explored. The purpose of this study was to explore the associations between personality traits and adherence to ADHD medication, beliefs about the medication, and perceptions of ADHD.

METHOD

Adolescents (n = 99) on ADHD medication were administered: Health-Relevant Personality Traits Five-Factor Inventory, Medication Adherence Report Scale, Beliefs about Medicines Specific and Brief Illness Perceptions Questionnaires.

RESULTS

The personality trait Antagonism correlated with adherence behaviour (r = - 0.198, p = 0.005) and perceived personal control of ADHD (r = - 0.269, p = 0.007). Negative Affectivity correlated with beliefs regarding necessity (r = 0.319, p = 0.001), concerns (r = 0.344, p = 0.001), and experienced side effects of medication (r = 0.495, p = 0.001), alongside perceptions regarding duration (r = 0.272, p = 0.007), identity (r = 0.388, p < 0.001), being emotionally affected (r = 0.374, p < 0.01), personal control (r = - 0.287, p = 0.004) and concerns about ADHD (r = 0.465, p < 0.001). Impulsivity correlated with perceived consequences (r = - 0.226, p = 0.0255) and personal control of ADHD (r = - 0.379, p < 0.001). Hedonic Capacity correlated with concerns about medication (r = - 0.218, p = 0.0316) and perceived identification with ADHD (r = - 0.203, p = 0.045).

CONCLUSION

Personality traits are related to adherence, beliefs about ADHD medicines and perceptions of ADHD. Antagonism is associated with adherence, especially intentional non-adherence, while Negative Affectivity correlates with numerous perceptions of ADHD and beliefs about medications. Personality assessments could be useful in the care and treatment of adolescents with ADHD.

Stroop-like animal size test: Links with child effortful control, personality and problem behavior

This study examined children's performance on the Stroop-like animal size test and its relations to parent-reported temperamental effortful control, personality, and common emotional and behavioral problems in a Russian sample of 5-12-year-olds (N = 202). The animal size test demonstrated a Stroop-like effect for accuracy and response time (RT) in both genders and across all ages. Children's performance on the animal size test considerably improved with age such that older children performed more accurately, were faster and their responses were less variable than younger children's responses. The findings indicated that RT was negatively related to temperamental trait of effortful control and its key components, attention focusing and inhibitory control, whereas RT variability was negatively related to both regulatory traits, effortful control and conscientiousness, and their components. Children's performance on the AST was meaningfully related to hyperactivity-inattention, externalizing behavior and overall level of childhood psychopathology. These findings provide support for the usefulness of the animal size test in the neuropsychological assessment of preschool and school-age children.

The neurobiology of impulsivity and substance use disorders: implications for treatment

Impulsivity is strongly associated with substance use disorders (SUDs). Our review discusses impulsivity as an underlying vulnerability marker for SUDs, and treatment of co-occurring impulsivity in SUDs. Three factors should be considered for the complex relationship between impulsivity and a SUD: (1) the trait effect of impulsivity, centering on decreased cognitive and response inhibition, (2) the state effect resulting from either acute or chronic substance use on brain structure and function, and (3) the genetic and environmental factors (e.g., age and sex) may influence impulsive behavior associated with SUDs. Both subjective and objective measures are used to assess impulsivity. Together, treatment developments (pharmacological, behavioral, and neurophysiological) should consider these clinically relevant dimensions assessed by a variety of measures, which have implications for treatment matching in individuals with SUD. Despite its heterogeneity, impulsivity is a marker associated with SUDs and may be understood as an imbalance of bottom-up and top-down neural systems. Further investigation of these relationships may lead to more effective SUD treatments.

The Relations Between Temperament, Character, and Executive Functions in Children With ADHD and Clinical Controls

OBJECTIVE

The purpose of this study was to investigate the overlap between executive functions and temperament as measured by two questionnaires and to examine characteristic profiles in children with ADHD and clinical controls.

METHOD

Parents of 111 clinically referred children, half of whom were diagnosed with ADHD and half with other or no diagnoses, completed the Behavior Rating Inventory of Executive Function (BRIEF) and the Cloninger Junior Temperament and Character Inventory (JTCI).

RESULTS

Factor analysis of both instruments resulted in three common factors representing aspects of (1) cognitive regulation, (2) behavioral regulation, and (3) anxious/rigid tendencies. Factor (4) represented strengths and positive resources and loaded on JTCI scales only. Both instruments discriminated significantly between ADHD and non-ADHD children. Conduct disorder/oppositional defiant disorder (CD/ODD) but not ADHD accounted for problems in BRIEF Emotional Control and Self-Monitor and JTCI low Cooperativeness.

CONCLUSION

The two instruments only partially overlap and may complement each other.

COMMENTARY ON THE CHANGING NATURE OF EXECUTIVE CONTROL IN PRESCHOOL

In this commentary, I provide a critical evaluation of Espy and colleagues' proposal to use a bifactor modeling approach to characterize children's performance on executive control tasks. I draw attention to an old idea regarding treating items as causal or effect indicators of their latent constructs. I remind readers that factor analytic approaches, including the bifactor model that is proposed here, assume that executive control tasks are effect indicators of the latent construct of executive control. I suggest that executive control tasks may be better conceptualized as causal indicators. I further suggest that these different modeling approaches will result in markedly different conclusions about the nature of executive control-including predictors and outcomes of executive control that were the focus of this monograph.

Observed temperament from ages 6 to 36 months predicts parent- and teacher-reported attention-deficit/hyperactivity disorder symptoms in first grade

This study tested the prospective association between observational indicators of temperament, which were obtained across multiple assessments when children were 6-36 months of age, and parent and teacher reports of children's attention-deficit/hyperactivity disorder (ADHD) behaviors, when children were in first grade. Data were drawn from the Family Life Project and included 1,074 children for whom temperament and either parent- or teacher-reported ADHD behavioral data were available. The results of variable-centered regression models indicated that individual differences in temperament regulation, but not temperamental reactivity, was uniquely predictive of parent- and teacher-reported ADHD behaviors. Latent profile analyses were used to characterize configurations of temperamental reactivity and regulation. Person-centered regression models were subsequently estimated in which temperamental profile membership replaced continuous indicators of temperamental reactivity and regulation as predictors. The results of person-centered regression models indicated that temperamental reactivity and regulation both contributed (both alone and in combination) to the prediction of subsequent ADHD behaviors. In general, the predictive associations from early temperament to later ADHD were of modest magnitude (R 2 = .10-.17). Results are discussed with respect to interest in the early identification of children who are at elevated risk for later ADHD.

Attention deficits and hyperactivity-impulsivity: what have we learned, what next?

The domains of self-regulation, self-control, executive function, inattention, and impulsivity cut across broad swathes of normal and abnormal development. Attention-deficit/hyperactivity disorder is a common syndrome that encompasses a portion of these domains. In the past 25 years research on attention-deficit/hyperactivity disorder has been characterized by dramatic advances in genetic, neural, and neuropsychological description of the syndrome as well as clarification of its multidimensional phenotypic structure. The limited clinical applicability of these research findings poses the primary challenge for the next generation. It is likely that clinical breakthroughs will require further refinement in describing heterogeneity or clinical/biological subgroups, renewed focus on the environment in the form of etiological events as well as psychosocial contexts of development, and integration of both with biological understanding.

ADHD and personality: a meta-analytic review

We report a meta-analysis of up to 40 data sets that examined the personality dimensions in the Five-Factor Model (FFM) and the integrated Five-Factor Model (IFFM) in relation to ADHD symptom domains of inattention (IA) and hyperactivity/impulsivity (HI). The IFFM incorporated the dimensions of other personality models (in particular, those of Eysenck, Tellegen, and Cloninger, as well as the FFM). Major findings were: (1) IA and HI were both associated with low conscientious inhibition/conscientiousness, and low agreeable inhibition/agreeableness, and with high negative emotionality/neuroticism; (2) conscientious inhibition and conscientiousness were more strongly related to IA than HI; (3) agreeable inhibition and agreeableness were more strongly related to HI than IA; and (4) the association of conscientious inhibition and conscientiousness with HI was moderated by age group and source from where participants were recruited (associations were stronger in children than adults, and clinical samples than community samples). These findings are discussed in relation to single and multiple pathway theories, underlying factors and processes for the personality-ADHD link, and clinical implications.

Ventral-striatal responsiveness during reward anticipation in ADHD and its relation to trait impulsivity in the healthy population: a meta-analytic review of the fMRI literature

A review of the existing functional magnetic resonance imaging (fMRI) studies on reward anticipation in patients with attention-deficit/hyperactivity disorder (ADHD) is provided. Meta-analysis showed a significant medium effect size (Cohen's d=0.48-0.58) in terms of ventral-striatal (VS)-hyporesponsiveness in ADHD. Studies on VS-responsiveness and trait impulsivity in the healthy population demonstrate the opposite relationship, i.e. impulsivity-scores positively correlated with VS activation during reward processing. Against the background that ADHD may represent an extreme on a continuum of normal variability, the question arises as to how these contrasting findings can be integrated. We discuss three theoretical approaches, each of which integrates the opposing findings: (1) an inverted-u-shape model; (2) a (genetic) moderator model; and (3) the "unrelated model". We conclude that at the present stage the number of existing studies in the healthy population as well as in ADHD groups is too small for a final answer. Therefore, our presented integrative approaches should be understood as an attempt to frame future research directions by generating testable hypotheses and giving practical suggestions for future studies.

The Schedule for Nonadaptive and Adaptive Personality for Youth (SNAP-Y): a new measure for assessing adolescent personality and personality pathology

The Schedule for Nonadaptive and Adaptive Personality-Youth Version (SNAP-Y) is a new, reliable self-report questionnaire that assesses 15 personality traits relevant to both normal-range personality and the alternative DSM-5 model for personality disorder. Community adolescents, 12 to 18 years old (N = 364), completed the SNAP-Y; 347 also completed the Big Five Inventory-Adolescent, 144 provided 2-week retest data, and 128 others completed the Minnesota Multiphasic Personality Inventory-Adolescent. Outpatient adolescents (N = 103) completed the SNAP-Y, and 97 also completed the Minnesota Multiphasic Personality Inventory-Adolescent. The SNAP-Y demonstrated strong psychometric properties, and structural, convergent, discriminant, and external validities. Consistent with the continuity of personality, results paralleled those in adult and college samples using the adult Schedule for Nonadaptive and Adaptive Personality-Second Edition (SNAP-2), from which the SNAP-Y derives and which has established validity in personality-trait assessment across the normal-abnormal continuum. The SNAP-Y thus provides a new, clinically useful instrument to assess personality traits and personality pathology in adolescents.

The hierarchical structure of childhood personality in five countries: continuity from early childhood to early adolescence

Childhood personality is a rapidly growing area of investigation within individual differences research. One understudied topic is the universality of the hierarchical structure of childhood personality. In the present investigation, parents rated the personality characteristics of 3,751 children from 5 countries and 4 age groups. The hierarchical structure of childhood personality was examined for 1-, 2-, 3-, 4-, and 5-factor models across country (Canada, China, Greece, Russia, and the United States) and age group (3-5, 6-8, 9-11, and 12-14 years of age). Many similarities were noted across both country and age. The Five-Factor Model was salient beginning in early childhood (ages 3-5). Deviations across groups and from adult findings are noted, including the prominent role of antagonism in childhood personality and the high covariation between Conscientiousness and intellect. Future directions, including the need for more explicit attempts to merge temperament and personality models, are discussed.

Sustained attention and behavioral characteristics associated with ADHD in adults

The goal of the current study was to investigate whether two cognitive functions (i.e., sustained attention and response inhibition) were related to a general model of personality traits and behavioral characteristics associated with attention-deficit hyperactivity disorder (ADHD). To examine these relations, the Conjunctive Continuous Performance Test was used to measure the two cognitive functions, the Mini-Marker was used to measure the Big Five domains of personality, and the Wender Utah Rating Scale (WURS) was used to index ADHD symptoms. Correlations and multiple regression analyses showed that difficulties in sustained attention were associated with the WURS behavioral symptoms of inattention, oppositional/defiant behavior, impulsivity, and Big Five low conscientiousness, but were not associated with emotional problems such as neuroticism or low agreeableness (Big Five). Difficulties in response inhibition were marginally correlated with behavioral symptoms of inattention and low conscientiousness. Surprisingly, response inhibition was also highly correlated with sustained attention. In addition, neuroticism independently was highly associated with the WURS emotional and oppositional/defiant behavior symptoms. The findings suggest that deficient sustained attention relates specifically to the main ADHD behaviors but not to the emotional problems typically associated with the disorder.

The role of temperament and personality in problem behaviors of children with ADHD

This study describes temperament, personality, and problem behaviors in children with Attention-Deficit Hyperactivity Disorder (ADHD) aged 6 to 14 years. It targets differences between an ADHD sample (N = 54; 43 boys) and a large community sample (N = 465; 393 boys) in means and variances, psychometric properties, and covariation between traits and internalizing and externalizing problems. Parents rated their children on Buss and Plomin's and Rothbart's temperament models, a child-oriented five-factor personality model and also on problem behavior. Relative to the comparison group, children with ADHD presented with a distinct trait profile exhibiting lower means on Effortful Control, Conscientiousness, Benevolence and Emotional Stability, higher means on Emotionality, Activity, and Negative Affect, but similar levels of Surgency, Shyness, and Extraversion. Striking similarities in variances, reliabilities and, in particular, of the covariation between trait and maladjustment variables corroborate the spectrum hypothesis and suggest that comparable processes regulate problem behavior in children with and without ADHD.

The structure of effortful control in preschoolers and its relation to externalizing problems

The first aim of the present study was to examine the structure of effortful control. The second aim was to determine whether components of effortful control relate to conduct problems and hyperactivity. Effortful control was measured in 3-year-old children (N= 89) with an observational measure, the effortful control battery (ECB), and a parent report, the Children's Behaviour Questionnaire (CBQ). Principal component analysis showed that the ECB measures five components, assessing two higher-order constructs, which can be labelled as Self-Control and Attention/Motor Control. The five scales of the CBQ appeared to measure one construct - a more general measure of effortful control. The components and constructs of the ECB as well as the scales of the CBQ were differently related to conduct problems and hyperactivity. Conduct problems were most strongly predicted by observed Delay of Gratification and parent-reported Inhibitory Control, whereas Hyperactivity was most strongly predicted by observed Delay of Gratification, and the higher-order construct Attention/Motor Control, as well as parent-reported Attentional Focusing and Inhibitory Control. It is important to keep in mind that effortful control is composed of heterogeneous components, all having their own unique values.