The unity and diversity of inattention and hyperactivity/impulsivity in ADHD: evidence for a general factor with separable dimensions

Development of a human-analogue, 3-symptom domain Dog ADHD and Functionality Rating Scale (DAFRS)

The family dog, in its natural environment, exhibits neuropsychological deficits redolent of human psychiatric disorders, including behaviours that are similar to human attention-deficit/hyperactivity disorder (ADHD) symptoms. Based on standard questionnaire methods in humans, we aimed to develop and validate a detailed, psychometrically improved tool to assess owner views on relevant dog behaviours. We modified available questionnaires by adding items that allow for separate analysis of impulsivity, and items on functional impairment. We collected data from 1168 owners for different validation steps of the new questionnaire and, similarly to assessment of humans where teachers also evaluate as an expert control, we collected data from dog trainers. Exploratory and confirmatory factor analysis revealed 3 factors: inattention (IA), hyperactivity (H) and impulsivity (I), corresponding to all three human symptom dimensions in dogs. Test-retest analyses showed excellent agreement between measurements for all factors. Similarly to findings with humans, trainer-owner rating comparisons showed fair (IA) to moderate (H, I) agreement. As in humans, greater ADHD scores were associated with greater functional impairment scores. We suggest that in dogs, similarly to humans, parallel examination of (extreme) ADHD and functional impairment scores could help distinguish diagnosable individuals, after further validation of the questionnaire using a relevant behaviour test.

Screen Time and ADHD Behaviors in Chinese Children: Findings From Longitudinal and Cross-Sectional Data

OBJECTIVE

Research suggests that screen exposure presents a risk for ADHD behaviors in young children. However, the operationalization of screen exposure remains murky and longitudinal data is scarce. In this paper, we examined the relations between better operationalized daily screen time and behaviors of inattention and behaviors of hyperactivity/impulsivity in three cohorts of community samples of young Chinese children.

METHOD

Study 1 was longitudinal and included 111 children who were 3.6 years old (Range = 2.4-4.9; SD = 0.4) at Baseline and 4.8 years old (Range = 3.9-6.0; SD = 0.4) at Follow-Up. Study 2 was cross-sectional and included 172 children aged 4.9 years (Range = 3.0-7.1; SD = 1.0). Study 3 was also cross-sectional and included 313 children who were 6.9 years old (Range = 5.7-8.3; SD = 0.4). In each study, the parents reported how much time that their children spent daily on iPad/tablet, smart phone, and online games and watching TV in the previous week, and their children's behaviors of inattention (I/A) and hyperactivity/impulsivity (H/I).

RESULTS

Regression analysis revealed that in Study 1, controlling for child demographics, mother's education, family SES, and corresponding I/A or H/I scores at Baseline, screen time at Baseline predicted I/A scores (β = .27, p < .01) and H/I scores (β = .32, p < .001) at Follow-Up. Similarly, controlling for covariates, screen time predicted I/A scores (β = .25, p < .01) and H/I scores (β = .25, p < .01) in Study 2; I/A scores (β = 0.16, p < .01) and H/I scores (β = .15, p < .05) in Study 3.

CONCLUSION

Screen exposure was a risk for inattention and hyperactivity/impulsivity behaviors in urban Chinese children.

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.

The factor structure of attention-deficit/hyperactivity disorder in schoolchildren

BACKGROUND

Most studies support a bifactor model of childhood ADHD with two specific factors. However, several studies have not compared this model with a bifactor model with three specific factors, few have tested the actual strength of the factors, and none have examined whether "talks excessively" should be treated as a hyperactivity versus impulsivity symptom in children with ADHD.

AIMS

To examine the factor structure of ADHD symptoms and evaluate the relative strength of potential factors.

METHODS

Parent-reports on the ADHD-Rating Scale (ADHD-RS-IV) were collected for 2044 schoolchildren from the general population and 147 children with ADHD from a clinical sample. Single-, two- and three-(correlated and bi-)factor models were tested using confirmatory factor analysis.

RESULTS

Most models had a satisfactory fit. However, a correlated three-factor model where "talks excessively" was included as an indicator of impulsivity, and especially a bifactor model with one strong, well-defined general and two/three (ICD-10 defined) weak specific factors fit the data slightly better than the remaining models.

CONCLUSIONS

The factor structure is best characterized by a bifactor model with a strong general factor and two/three weaker specific factors. Therefore, we suggest emphasizing the ADHD-RS-IV total score rather than the subscale scores in clinical practice.

Characterizing the Neural Correlates of Response Inhibition and Error Processing in Children With Symptoms of Irritability and/or Attention-Deficit/Hyperactivity Disorder in the ABCD Study®

Attention-deficit/hyperactivity disorder (ADHD), characterized by symptoms of inattention and/or hyperactivity and impulsivity, is a neurodevelopmental disorder associated with executive dysfunctions, including response inhibition and error processing. Research has documented a common co-occurrence between ADHD and pediatric irritability. The latter is more characterized by affective symptoms, specifically frequent temper outbursts and low frustration tolerance relative to typically developing peers. Shared and non-shared neural correlates of youths with varied profiles of ADHD and irritability symptoms during childhood remain largely unknown. This study first classified a large sample of youths in the Adolescent Brain Cognitive Development (ABCD) study at baseline into distinct phenotypic groups based on ADHD and irritability symptoms (N = 11,748), and then examined shared and non-shared neural correlates of response inhibition and error processing during the Stop Signal Task in a subset of sample with quality neuroimaging data (N = 5,948). Latent class analysis (LCA) revealed four phenotypic groups, i.e., high ADHD with co-occurring irritability symptoms (n = 787, 6.7%), moderate ADHD with low irritability symptoms (n = 901, 7.7%), high irritability with no ADHD symptoms (n = 279, 2.4%), and typically developing peers with low ADHD and low irritability symptoms (n = 9,781, 83.3%). Latent variable modeling revealed group differences in the neural coactivation network supporting response inhibition in the fronto-parietal regions, but limited differences in error processing across frontal and posterior regions. These neural differences were marked by decreased coactivation in the irritability only group relative to youths with ADHD and co-occurring irritability symptoms and typically developing peers during response inhibition. Together, this study provided initial evidence for differential neural mechanisms of response inhibition associated with ADHD, irritability, and their co-occurrence. Precision medicine attending to individual differences in ADHD and irritability symptoms and the underlying mechanisms are warranted when treating affected children and families.

The relationship between executive function, processing speed, and attention-deficit hyperactivity disorder in middle childhood

Attention-Deficit Hyperactivity Disorder (ADHD) is a heterogeneous disorder that is highly impairing. Early, accurate diagnosis maximizes long-term positive outcomes for youth with ADHD. Tests of executive functioning (EF) are potential tools for screening and differential diagnosis of ADHD subtypes. However, previous research has been inconsistent regarding the specificity and magnitude of EF deficits across ADHD subtypes. Here, we advance knowledge of the EF-ADHD relationship by using: (1) dimensional latent factor models of ADHD that captures the heterogeneity of expression, and (2) a comprehensive, reliable battery of EF tasks and modeling relationships with a general factor of EF ability. We tested 1548 children and adolescents (ages 7-15 years) from the Texas Twin Project, a population-based cohort with a diverse socioeconomic and ethnic composition. We show that EF deficits were specific to the inattention domain of ADHD. Moreover, we found that the association between EF task performance and inattention was stable across sociodemographic groups. Our results demonstrate that failures of executive control are selectively manifested as covert inattentive symptoms, such as trouble with organization, forgetfulness, and distractedness, rather than overt symptoms, such as inappropriate talkativeness and interruption. Future research, utilizing a bifactor characterization of ADHD in clinical samples, is needed to further refine understanding of the nature of cognitive deficits in ADHD across the full range of symptom variation.

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.

Longitudinal Temperament Pathways to ADHD Between Childhood and Adolescence

The current investigation extended prior cross-sectional mapping of etiological factors, transdiagnostic effortful and affective traits, and ADHD symptoms to longitudinal pathways extending from two etiological domains: polygenic and prenatal risk. Hypotheses were (1) genetic risk for ADHD would be related to inattentive ADHD symptoms in adolescence and mediated by childhood effortful control; (2) prenatal smoking would be related to hyperactive-impulsive ADHD symptoms during childhood and mediated by childhood surgency; and (3) there would be age-related variation, such that mediation of genetic risk would be larger for older than younger ages, whereas mediation of prenatal risk would be larger in earlier childhood than at later ages. Participants were 849 children drawn from the Oregon ADHD-1000 Cohort, which used a case control sample and an accelerated longitudinal design to track development from childhood (at year 1 ages 7-13) through adolescence (at year 6 ages 13-19). Results showed the mediational pathway from prenatal smoking through surgency to hyperactivity-impulsivity at Year 1 was significant (indirect effect estimate = .053, p < .01). The mediational pathway from polygenic risk through effortful control to inattention at Year 6 was also significant (indirect effect estimate = .084, p < .01). Both results were independent of the association between inattention and hyperactivity-impulsivity and control for the alternative etiological input and held across parent- and teacher-report of ADHD symptoms. In line with dual pathway models of ADHD, early prenatal risk for hyperactivity-impulsivity appears to operate through surgency, while polygenic genetic risk for inattention appears mediated by effortful control.

ADHD symptoms, the current symptom scale, and exploratory structural equation modeling: A psychometric study

The aim of the study was to use exploratory structural equation modelling (ESEM) to investigate support for an ADHD factor model with group factors for inattention (IA), hyperactivity (HY), and impulsivity (IM), as proposed in in ICD-10. A total of 202 adults (121 females and 81 males), aged between 18 and 35 years, from the general community, completed the Current Symptoms Scale (CSS). The results for the model showed good global fit, good convergent and divergent validities. However, the IA and IM factors, but not the HY factor, were clearly defined and demonstrated acceptable reliabilities. Taken together, these finding indicate that a revised ESEM model without the HY factor (i.e. with only the IA and IM symptoms) is an appropriate structure for modeling adult ratings of the ADHD behaviors described in the CSS. The taxonomic, theoretical and clinical implications of the findings for ADHD in general are discussed.

Age and Gender Measurement Noninvariance of the Adult ADHD Self-Report Scale Screener

Objective: The nature and form of demographics-related differences in ADHD self-reported symptoms across adulthood is currently poorly understood. This study explored the psychometrics of the Adult ADHD Self-Report Scale Screener (ASRS-6), including its age- and gender-related measurement invariance. Method: Structural equation models were used to analyze adult data-aged 16 to 95 years-from the 2007 British Adult Psychiatric Morbidity Survey. Results: The three-factor model (disorganization, inattention, hyperactivity) outperformed one- and two-factor models. Self-reported attentional deficits may be more pathognomonic of overall self-reported ADHD in adults than other symptoms. All items exhibited age measurement noninvariance while only a subset exhibited gender measurement noninvariance. Individuals who are male and younger tend to have lower thresholds for endorsement for ASRS-6 items than individuals who are female and older. Conclusion: The ASRS-6 does not appear to be unidimensional, and self-reported ASRS-6 symptomatology changes in meaning with age.

Investigating the Role of Inattention and/or Hyperactivity/impulsivity in Language and Social Functioning Using a Dimensional Approach

The current study parsed out the distinct components of attention-deficit/hyperactivity disorder (ADHD) symptomatology to examine differential relations with language and social ability. Using a research domain criteria (RDoC) framework, we administered standardized tests and previously developed and validated questionnaires to assess levels of inattention and/or hyperactivity/impulsivity symptomatology, language, social responsivity and social competency in 98 young adults. Those with higher inattention and/or hyperactivity/impulsivity symptomatology had reduced language comprehension, social responsivity, and social competency. Inattention and hyperactivity/impulsivity both predicted language comprehension, but not language production. Interestingly, inattention uniquely contributed to social responsiveness and social competency, but hyperactivity/impulsivity did not. Findings suggest that inattention and/or hyperactivity/impulsivity symptoms, inattention in particular, may be especially important for social skills programs geared towards individuals with attention limitations.

Executive Functions and Morphosyntax: Distinguishing DLD From ADHD in French-Speaking Children

Attention deficit hyperactivity disorder (ADHD) is commonly associated with deficits in executive functions executive functions (EF), but children with this disorder frequently demonstrate co-occurring morphosyntactic impairment when assessed using standardized tests. On the other hand, children with developmental language disorder (DLD), a population defined by impaired linguistic functioning, are often diagnosed with comorbid EF deficits. We investigated EF and morphosyntax in 60 French-speaking children aged six to 12: 20 with typical development (TD), 20 with ADHD, and 20 with DLD. To obtain an EF profile for the different cognitive groups, we used standardized tests to assess lower-order EF skills, (i) selective attention and (ii) short-term memory capacity, and higher-order EF skills, (i) working memory capacity and (ii) attention shifting. To test morphosyntax, we used (i) a standardized omnibus test that elicited a variety of complex structures and (ii) a more fine-grained probe test that assessed the production of third person object clitic pronouns, a clinical marker of DLD in French. Children with ADHD and DLD were associated with different EF and morphosyntactic profiles: children in the ADHD group demonstrated higher-order EF weakness and difficulty on the omnibus morphosyntax task, whereas children with DLD showed both lower- and higher-order limitations and struggled with both morphosyntax tasks. Our findings indicate that deficits in morphosyntax are not characteristic of ADHD but that the performance of children with ADHD can mimic morphosyntactic impairment when all-encompassing omnibus tests evaluating various and unpredictable structures are used. If morphosyntax is tested using reliable markers of atypical language development and external cognitive-load factors are optimally reduced, there are significant discrepancies in the observed ADHD-DLD outcomes. Clinical implications that include perspectives for the differential diagnosis of ADHD and DLD are discussed.

Adult ADHD Self-Report Scale: Comprehensive Psychometric Study in a Spanish SUD Sample

Objective: The purpose of this study is to provide reliability and validity evidence of the Adult Self-Report Scale (ASRS) scores on different versions and scoring procedures in a Spanish substance use disorder (SUD) sample. Method: The sample was made up of 170 outpatients diagnosed with SUD. The ASRS, the Mini-International Neuropsychiatric Interview (MINI), and the Substance Dependence Severity Scale were administered. Results: The results of the confirmatory factor analysis (CFA) showed adequate fit to the structure proposed by the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) in the 18-item version. On the screening scale, best fit was found for a model with two correlated factors (inattention and hyperactivity). The exploratory factor analysis (EFA) showed that the ADHD items converge and are differentiated from symptoms of withdrawal. The regression analyses showed that severity of dependence is explained by the ASRS scores. Conclusion: Both versions of the ASRS showed adequate psychometric properties. The polytomous or dichotomous score is relevant in patient classification.

Commentary on Application of the Bifactor S-1 Model to Multisource Ratings of ADHD/ODD Symptoms: An Appropriate Bifactor Model for Symptom Ratings

My commentary is organized into four sections. First, I summarize the reasons for the original interest in fitting symmetric bifactor models to ADHD data. Second, I summarize the concerns that Burns and colleagues raised with respect to fitting symmetric bifactor models to ADHD item-level data and describe their recommended alternative approach. Third, I raise two concerns that I had with their manuscript. Fourth, I conclude with a caveat and a general question about the merits of the continued study of the factor structure of ADHD symptoms.

The Effect of Sleep Deprivation on Recognition of Ambiguous Emotional Facial Expressions in Individuals With ADHD

Objective: The present study sought to investigate whether young adults with ADHD have more difficulty recognizing emotional facial expressions compared with young adults without ADHD, and whether such a difference worsens following sleep deprivation. Method: Thirty-one young men (M = 25.6) with (n = 15) or without (n = 16) a diagnosis of ADHD were included in this study. The participants were instructed to sleep 7 hr or more each night for one week, and their sleep quality was monitored via actigraph. Subsequently, the participants were kept awake in a controlled environment for 30 hr. The participants completed a visual emotional morph task twice-at the beginning and at the end of this period. The task included presentation of interpolated face stimuli ranging from neutral facial expressions to fully emotional facial expressions of anger, sadness, or happiness, allowing for assessment of the intensity threshold for recognizing these facial emotional expressions. Results: Actigraphy data demonstrated that while the nightly sleep duration of the participants with ADHD was similar to that of participants without ADHD, their sleep efficiency was poorer. At the onset of the experiment, there were no differences in recognition thresholds between the participants with ADHD and those without ADHD. Following sleep deprivation, however, the ADHD group required clearer facial expressions to recognize the presence of angry, sad, and, to a lesser extent, happy faces. Conclusion: Among young adults with ADHD, sleep deprivation may hinder the processing of emotional facial stimuli.

Does Inattention and Hyperactivity Moderate the Relation Between Speed of Processing and Language Skills?

The causal role of speed of processing (SOP) in developmental language disorder (DLD) is unclear given that SOP has been implicated in other neurodevelopmental disorders such as attention-deficit/hyperactivity disorder. This study investigated associations between SOP, language, and inattention/hyperactivity in a U.K. epidemiological cohort (N = 528). Monolingual children from a range of socioeconomic backgrounds were assessed longitudinally; at ages 5-6 (2012/2013) and 7-8 years (2014/2015). Persistent weaknesses in SOP characterized children with DLD but did not predict language longitudinally. Ratings of inattention/hyperactivity moderated the association between SOP and language, indicating that SOP deficits are particularly detrimental for language when coupled with poor attention/hyperactivity. SOP may be a shared risk factor for DLD and inattention/hyperactivity or a general marker of neurodevelopmental disorder.

Early life predictors of attention deficit/hyperactivity disorder symptomatology profiles from early through middle childhood

This study used repeated measures data to identify developmental profiles of elevated risk for ADHD (i.e., six or more inattentive and/or hyperactive-impulsive symptoms), with an interest in the age at which ADHD risk first emerged. Risk factors that were measured across the first 3 years of life were used to predict profile membership. Participants included 1,173 children who were drawn from the Family Life Project, an ongoing longitudinal study of children's development in low-income, nonmetropolitan communities. Four heuristic profiles of ADHD risk were identified. Approximately two thirds of children never exhibited elevated risk for ADHD. The remaining children were characterized by early childhood onset and persistent risk (5%), early childhood limited risk (10%), and middle childhood onset risk (19%). Pregnancy and delivery complications and harsh-intrusive caregiving behaviors operated as general risk for all ADHD profiles. Parental history of ADHD was uniquely predictive of early onset and persistent ADHD risk, and low primary caregiver education was uniquely predictive of early childhood limited ADHD risk. Results are discussed with respect to how changes to the age of onset criterion for ADHD in DSM5 may affect etiological research and the need for developmental models of ADHD that inform ADHD symptom persistence and desistance.

Structure of ADHD/ODD Symptoms in Spanish Preschool Children: Dangers of Confirmatory Factor Analysis for Evaluation of Rating Scales

Confirmatory factor analysis (CFA) is often used to evaluate attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) symptom ratings by parents and teachers. An ADHD-inattention (IN), ADHD-hyperactivity/impulsivity (HI), and ODD three-factor model is usually the best model. Acceptable CFA models, however, can hide symptoms with poor convergent and discriminant validity. To demonstrate this issue, CFA models (i.e., cross-loadings set to zero) along with exploratory CFA models (i.e., cross-loadings allowed) were applied to parent (n = 308) and teacher (n = 258) ratings of ADHD/ODD symptoms with Spanish preschool children (M_age = 4.78, SD = .84, 56% boys). While the three-factor CFA model provided an acceptable-fit with moderate to substantial symptom-factor loadings, the three-factor exploratory CFA model, however, found a large number of the symptoms failed to show convergent and discriminant validity. These outcomes argue for the use of exploratory CFA procedures in the initial evaluation of ADHD/ODD rating scales.

Should We Subtype ADHD According to the Context in Which Symptoms Occur? Criterion Validity of Recognising Context-Based ADHD Presentations

ADHD symptoms show considerable individual variation in the contexts in which they are expressed. It has previously been proposed that subtyping individuals according to the contexts in which symptoms are expressed may be clinically useful. We examined context-based patterns of ADHD symptoms in a longitudinal cohort study of n = 1388 children, as well as context-specific and context-general predictors of symptoms. Participants were community-ascertained and provided ADHD symptom data at ages 7, 9, and 11. Using growth mixture modelling we identified five inattention and five hyperactivity/impulsivity categories that differed in the developmental patterns of symptoms reported by parent and teacher informants. We found some evidence that context-specific predictors were related to context-specific expressions. Specifically, after controlling for other risk factors for ADHD symptoms, relationships with teachers predicted school-specific (teacher-reported) but not home-specific (parent-reported) symptom levels. However, no subtypes defined by exclusively home-based symptoms emerged, suggesting that while symptoms may sometimes be specific to the school context, they are only rarely confined to the home context. Subtyping by context could be informative; however, further work will required to uncover the nature of any etiological, functional, or outcome differences between those who show symptom expression in different contexts.

Increased risk of ADHD in families with ASD

Attention Deficit and Hyperactive Disorder (ADHD) and Autism Spectrum Disorders (ASD) are frequent comorbid neurodevelopmental conditions and the overlap between both disorders remains to be delineated. A more complete understanding of the shared genetic and environmental factors is needed. Using a family-based method, we evaluated the risk of ADHD in a group of relatives with an ASD proband (ASD-) and a group of relatives with an ASD and ADHD proband (ASD+). We enrolled 1245 individuals in the study: 499 probands, their 746 first-degree relatives and 140 controls. We used a multivariate generalized estimating equation (GEE) model, in which the dependent variable was the ADHD diagnosis in the relatives and the independent variable the ASD+ or ASD- in probands. We adjusted for sociodemographic factors (age, sex, IQ) and for the nature of the familial relationship with the affected proband (parent or sibling). Among the probands, there were 287 ASD- and 212 ASD+ individuals. ADHD was more frequent in relatives (19%) than in the control group (7%) (p = 0.001). The risk of ADHD was higher in the ASD+ relatives group than in the ASD- relatives group (GEE model OR 1.58 [95% CI 1.04-2.38], p = 0.032). This result was found in parents (OR 1.96 [95% CI  1.14-3.36], but not in siblings (OR 1.28 [95% CI 0.84-1.94], p = 0.434). Our study provides a representative estimate of the family distribution of ADHD in relatives of ASD probands but supports the modest effect of shared genetic and environmental factors between both disorders.

Psychometric Properties and Structures of the IAT, GPIUS and GAS Scales: A Bifactor Approach

This study applied a bifactor approach to investigate the structures and simultaneously compare the psychometric properties of three popular self-report internet addiction (IA) instruments. A bifactor confirmatory factor analysis was used to address the structures of the three scales, while the bifactor multidimensional item response model was employed to compare the psychometric properties of the three scales. Results of bifactor confirmatory factor analysis (CFA) showed that the bifactor structures were suitable for the three scales. These corresponding bifactor structures were used in the subsequent bifactor multidimensional item response theory (MIRT) analysis. Results of the bifactor MIRT showed that: three instruments of IA performed well as a whole; the Generalised Problematic Internet Use Scale (GPIUS) and Internet Addiction Test (IAT) provided more test information and had less standard error of measurement, which ranged from −3 to −1 standard deviations of theta or IA severity; the Game Addiction Scale (GAS) performed better than the other two scales in that it can provide more test information in the large area of IA severity (from −1 to +3 SDs). These suggest that the GPIUS and IAT may be the best choice for epidemiological IA studies and for measuring those with lower IA severity. Meanwhile, the GAS may be a good choice when we recruit those with various levels of IA severity.

Examination of the Structure and Measurement of Inattentive, Hyperactive, and Impulsive Behaviors from Preschool to Grade 4

Attention Deficit/Hyperactivity Disorder (ADHD) is a complex and heterogeneous disorder consisting of inattentive and hyperactive/impulsive behaviors. Although, the multidimensionality of ADHD is widely accepted, questions remain regarding the extent to which the components of this disorder are overlapping or distinct. Further, although the same measures are generally used to assess inattentive, hyperactive, and impulsive behaviors across childhood, it has been argued that the structure and measurement of inattentive, hyperactive, and impulsive behaviors may be susceptible to developmental influences. The purpose of this study was to examine the factor structure and measurement invariance of inattentive and hyperactive/impulsive behaviors in a large group of children (N = 10,047) ranging in grade level from preschool to grade 4. A bifactor model with a general factor and two specific factors of inattention and hyperactivity/impulsivity fit the data best. This finding held across all groups and all grade levels. In general, the bifactor model demonstrated measurement invariance from kindergarten through grade 4 but not for preschool. Implications for the understanding and measurement of inattentive, hyperactive, and impulsive behaviors across early and middle childhood are discussed.

Validity of the ADHD Bifactor Model in General Community Samples of Adolescents and Adults, and a Clinic-Referred Sample of Children and Adolescents

OBJECTIVE

This study examined the bifactor models of ADHD in three groups: adolescents from the general community ( n = 214), adults from the general community ( n = 366), and a clinic sample ( n = 245).

METHOD

For the adolescent sample, mothers provided ratings of the ADHD symptoms, and their teachers provided ratings for Emotional Symptoms, Conduct Problems, Hyperactivity, Peer Problems, and Prosocial Behavior. For the adult sample, all adults completed self-ratings of the ADHD symptoms and measures for depression, anxiety, and stress. For the clinic-referred sample, mothers provided ratings of the ADHD symptoms, and they were diagnosed for ADHD, Conduct Disorder/Oppositional Defiant Disorder, anxiety disorders, and depression disorders.

RESULTS

The findings for all samples supported the bifactor model, and there were differences in the way the general and specific factors correlated with the external variables.

CONCLUSION

The findings support the validity of the bifactor model.

The Australian Sheep-Goat Scale: An Evaluation of Factor Structure and Convergent Validity

The Australian Sheep-Goat Scale (ASGS) is a commonly used measure of belief in the paranormal. The scale contains items that index extrasensory perception (ESP), psychokinesis (PK), and life after death (LAD). Although, research employs the ASGS as both a general (unidimensional) and factorial (multidimensional) measure, few studies have examined the appropriateness of these solutions. Accordingly, the present paper tested the psychometric integrity of the ASGS via two studies. Study 1 assessed ASGS factorial structure using confirmatory factor analysis. To achieve this, merging of ASGS data from previously published studies and ongoing work created a heterogeneous sample of 1,601 responses. Analysis revealed that a two-factor bifactor model best explained ASGS organization. This comprised a general overarching factor incorporating two subfactors (ESP and PK). Factor loadings and omega reliability supported a unidimensional structure for the most part. Removal of LAD items improved model fit because the factor added unnecessary complexity and undermined scale psychometric integrity. Study 2, using a supplementary composite sample of 320 respondents, assessed the convergent validity of the emergent ASGS model against a recently published Revised Paranormal Belief Scale (RPBS) bifactor solution. Comparison revealed high convergent validity. The general ASGS factor, despite deriving from only psi-related dimensions (ESP and PK) predicted RPBS scores. This finding indicated that ASGS brevity relative to the RPBS is advantageous when assessing general belief in the paranormal. The ASGS, notwithstanding limited construct content, functions as an effective measure of paranormal belief. Additionally, Study 2 replicated the bifactor structure identified in Study 1 and invariance testing supported invariance of form, factor loadings and item intercepts for this solution across Studies 1 and 2.

Is Poor Working Memory a Transdiagnostic Risk Factor for Psychopathology?

In contrast to historical conceptualizations that framed psychological disorders as distinct, categorical conditions, it is now widely understood that co- and multi-morbidities between disorders are extensive. As a result, there has been a call to better understand the dimensional liabilities that are common to and influence the development of multiple psychopathologies, as supported and exemplified by the National Institutes of Mental Health (NIMH) Research Domain Criteria (RDoC) framework. We use a latent variable SEM approach to examine the degree to which working memory deficits represent a cognitive liability associated with the development of common and discrete dimensions of psychopathology. In a sample of 415 community recruited children aged 8-12 (n = 170 girls), we fit a bi-factor model to parent reports of behavior from the DISC-4 and BASC-2, and included a latent working memory factor as a predictor of the internalizing, externalizing, and general "p-factor." We found that both the general "p-factor" and externalizing (but not internalizing) latent factor were significantly associated with working memory. When a bi-factor model of externalizing symptomology was fit to further explore this relationship, working memory was only correlated with the general externalizing dimension; correlation with specific inattention, hyperactive/impulsive, and oppositional factors did not survive once the general externalizing dimension was taken into consideration. These findings held regardless of the sex of the child. Our results suggest that working memory deficits represent both a common cognitive liability for mental health disorders, and a specific liability for externalizing disorders.

DLGAP1 and NMDA receptor-associated postsynaptic density protein genes influence executive function in attention deficit hyperactivity disorder

Objective

To explore the association of DLGAP1 gene with executive function (EF) in attention deficit hyperactivity disorder (ADHD) children.

Method

A total of 763 ADHD children and 140 healthy controls were enrolled. The difference of EF between ADHD and controls was analyzed using the analysis of covariance (ANCOVA), with IQ, sex, and age as covariates. Both the associations of SNPs with EF and three symptom traits of ADHD were conducted using an additive linear regression model by PLINK with the same covariates as ANCOVA.

Results

Compared with controls, children with ADHD showed poorer cognitive flexibility and inhibition. Two SNPs (rs2049161, p-value = 5.08e-7, adjusted p-value = 1.63e-4, rs16946051, p-value = 5.18e-7, adjusted p-value = 1.66e-4) survived multiple tests in Trail Making Test. Both SNPs also showed association with TOH (rs2049161, p = 6.82e-4, rs16946051, p = 7.91e-4). Set-based analysis for gene DLGAP1 and its functional pathway DLGAP1-DLG4-NMDA showed they were associated with cognitive flexibility at both gene (p = .0057) and pathway level (p = .0321). Furthermore, the gene and pathway also showed association with ADHD symptom score. The associated SNPs and their LD proxies were related to the expression of DLGAP1 in medulla and frontal cortex.

Conclusion

Children with ADHD showed deficit in EF, especially, cognitive flexibility and inhibition. DLGAP1 was associated with cognitive flexibility and plan, and the role of DLGAP1 might be implemented through the complex of DLGAP1-DLG4-NMDA.

Genetic and phenotypic overlap of specific obsessive-compulsive and attention-deficit/hyperactive subtypes with Tourette syndrome

BACKGROUND

The unique phenotypic and genetic aspects of obsessive-compulsive (OCD) and attention-deficit/hyperactivity disorder (ADHD) among individuals with Tourette syndrome (TS) are not well characterized. Here, we examine symptom patterns and heritability of OCD and ADHD in TS families.

METHOD

OCD and ADHD symptom patterns were examined in TS patients and their family members (N = 3494) using exploratory factor analyses (EFA) for OCD and ADHD symptoms separately, followed by latent class analyses (LCA) of the resulting OCD and ADHD factor sum scores jointly; heritability and clinical relevance of the resulting factors and classes were assessed.

RESULTS

EFA yielded a 2-factor model for ADHD and an 8-factor model for OCD. Both ADHD factors (inattentive and hyperactive/impulsive symptoms) were genetically related to TS, ADHD, and OCD. The doubts, contamination, need for sameness, and superstitions factors were genetically related to OCD, but not ADHD or TS; symmetry/exactness and fear-of-harm were associated with TS and OCD while hoarding was associated with ADHD and OCD. In contrast, aggressive urges were genetically associated with TS, OCD, and ADHD. LCA revealed a three-class solution: few OCD/ADHD symptoms (LC1), OCD & ADHD symptoms (LC2), and symmetry/exactness, hoarding, and ADHD symptoms (LC3). LC2 had the highest psychiatric comorbidity rates (⩾50% for all disorders).

CONCLUSIONS

Symmetry/exactness, aggressive urges, fear-of-harm, and hoarding show complex genetic relationships with TS, OCD, and ADHD, and, rather than being specific subtypes of OCD, transcend traditional diagnostic boundaries, perhaps representing an underlying vulnerability (e.g. failure of top-down cognitive control) common to all three disorders.

Maternal obesity and attention-related symptoms in the preterm offspring

BACKGROUND

Maternal pre-pregnancy obesity, in term-born children, is associated with an increased risk of attention problems, however this relationship has not been explored among children born extremely preterm.

AIM

To estimate the risk of attention problems at age 10years in children born very preterm to overweight (i.e., body mass index (BMI) 25-29kg/m²) and obese (i.e., BMI≥30kg/m²) women relative to the risk among children born to women who were neither overweight nor obese (i.e. BMI<25kg/m²).

STUDY DESIGN

Multi-center prospective cohort study.

METHODS

A total of 764 children born before the 28th week of gestation and whose mother's pre-pregnancy height and pre-pregnancy weight were obtained at birth had an IQ≥70 at age 10years when parents and teachers completed Child Symptom Inventory-4 questionnaires that included items about the presence of ADHD.

RESULTS

Compared to children whose mother's pre-pregnancy weight was in the normal range (BMI<25kg/m²), children were at increased risk of parent-identified ADHD behaviors if their mother was overweight (odds ratio (OR)=1.9; 95% confidence interval (CI): 1.1, 3.3), or obese (OR=2.3; 95% CI: 1.4, 3.9). They were not at increased risk of teacher-identified ADHD characteristics if their mother was overweight before her pregnancy (OR=1.0; 95% CI: 0.6, 1.8), or obese (OR=1.0; 95% CI: 0.6, 1.6).

CONCLUSION

Maternal overweight and obesity are associated with increased risk of parent-identified ADHD characteristics at 10years of age in children born extremely preterm.

Child Executive Control as a Moderator of the Longitudinal Association Between Sleep Problems and Subsequent Attention-Deficit/Hyperactivity Disorder Symptoms

Objective

To examine the longitudinal associations among sleep, executive control (EC), and attention-deficit/hyperactivity disorder (ADHD) symptoms in childhood.

Methods

In this longitudinal study (N = 271), parents answered questions about sleep problems when children were 3 years old, children completed a comprehensive EC task battery at 4.5 years, and teachers completed standardized measures of child ADHD symptoms in 4th grade.

Results

Latent moderated structural equation models demonstrated that sleep problems at 3 years and EC deficits at 4.5 years were associated with ADHD symptoms in 4th grade. EC moderated the relationship between sleep problems and hyperactivity/impulsivity, such that children with both sleep problems and poor EC were particularly at risk for hyperactivity/impulsivity.

Conclusions

Sleep problems and EC deficits early in development were associated with increased risk for ADHD symptoms in elementary school. Early assessment and intervention to promote healthy sleep and EC development may be helpful in ADHD prevention.

Observer variability identifying attention deficit/hyperactivity disorder in 10-year-old children born extremely preterm

AIM

A DSM-5 diagnosis of attention deficit/hyperactive disorder (ADHD) requires that symptoms be present in two settings. We wanted to see how teachers and parents compare on their assessments.

METHODS

We evaluated how well Child Symptom Inventory-4 (CSI-4) reports from 871 parents and 634 teachers of 10-year-old children born before the 28th week of gestation provided information about indicators of school dysfunction.

RESULTS

Kappa values for parent and teacher agreement of any ADHD were at best fair to poor (<0.41). Nevertheless, ADHD identified by each alone provided a moderate amount of information about such indicators of school dysfunction as grade repetition. Only occasionally did agreement provide more information than provided by only one reporter. Mother's social class and intelligence level did not discriminate between parents who did and did not agree with the teacher.

CONCLUSION

ADHD identified by a single observer can provide appreciable information about a range of the child's functions needed for success in school and, therefore, should not be discounted when another observer does not consider the child to have ADHD symptoms.

Evaluating the Hierarchical Structure of ADHD Symptoms and Invariance Across Age and Gender

The bifactor model of attention-deficit/hyperactivity disorder (ADHD) has been extensively explored, yet the tendency of the bifactor model to overfit data necessitates investigation of alternative, more parsimonious models, such as a modified bifactor structure. The present study used item response theory to compare unidimensional, correlated factors, bifactor, and modified bifactor models of ADHD symptoms in a clinical sample of youth ( N = 1,612) and examined differential item functioning (DIF) by age (<11 and ≥11 years) and gender. Results suggested that two restricted bifactor models showed superior fit compared with alternative models, and support strong general and inattention dimensions, with unreliable hyperactivity and impulsivity dimensions. No DIF was found across gender or age. The present study confirms that the general dimension (i.e., inhibition) and one specific dimension (i.e., sustained attention) represent distinct variability in ADHD symptoms that may improve prediction of symptom persistence, treatment response, or functional outcomes.

Does Sluggish Cognitive Tempo Fit Within a Bi-Factor Model of ADHD?

OBJECTIVE

Studies demonstrate sluggish cognitive tempo (SCT) symptoms to be distinct from inattentive and hyperactive-impulsive dimensions of ADHD. No study has examined SCT within a bi-factor model of ADHD, whereby SCT may form a specific factor distinct from inattention and hyperactivity/impulsivity while still fitting within a general ADHD factor, which was the purpose of the current study.

METHOD

A total of 168 children were recruited from an ADHD clinic. Most (92%) met diagnostic criteria for ADHD. Parents and teachers completed measures of ADHD and SCT.

RESULTS

Although SCT symptoms were strongly associated with inattention, they loaded onto a factor independent of ADHD g. Results were consistent across parent and teacher ratings.

CONCLUSION

SCT is structurally distinct from inattention as well as from the general ADHD latent symptom structure. Findings support a growing body of research suggesting SCT to be distinct and separate from ADHD.

Systemic Inflammation during the First Postnatal Month and the Risk of Attention Deficit Hyperactivity Disorder Characteristics among 10 year-old Children Born Extremely Preterm

Although multiple sources link inflammation with attention difficulties, the only human study that evaluated the relationship between systemic inflammation and attention problems assessed attention at age 2 years. Parent and/or teacher completion of the Childhood Symptom Inventory-4 (CSI-4) provided information about characteristics that screen for attention deficit hyperactive disorder (ADHD) among 793 10-year-old children born before the 28th week of gestation who had an IQ ≥ 70. The concentrations of 27 proteins in blood spots obtained during the first postnatal month were measured. 151 children with ADHD behaviors were identified by parent report, while 128 children were identified by teacher report. Top-quartile concentrations of IL-6R, TNF-α, IL-8, VEGF, VEFG-R1, and VEGF-R2 on multiple days were associated with increased risk of ADHD symptoms as assessed by a teacher. Some of this increased risk was modulated by top-quartile concentrations of IL-6R, RANTES, EPO, NT-4, BDNF, bFGF, IGF-1, PIGF, Ang-1, and Ang-2. Systemic inflammation during the first postnatal month among children born extremely preterm appears to increase the risk of teacher-identified ADHD characteristics, and high concentrations of proteins with neurotrophic properties appear capable of modulating this increased risk.

Bifactor Models of Attention Deficit/Hyperactivity Symptomatology in Adolescents: Criterion Validity and Implications for Clinical Practice

This study evaluated the fit and criterion validity of a bifactor model for 18 DSM-IV attention deficit/hyperactivity disorder (ADHD) symptoms, along with nine supplementary symptoms that represented the manifestation of inattention and hyperactivity-impulsivity in adolescence and early adulthood. Participants included N = 172 adolescents who were diagnosed with combined type ADHD and who were enrolled in a treatment study. A bifactor model provided reasonably good fit to combined parent- and teacher-reported DSM symptoms and supplemental items at baseline prior to treatment. Across models, the general factor was characterized by high reliability (ω = .93, .95), while specific inattentive and hyperactive-impulsive factors were characterized by poor reliability (ω = .30-.50). With respect to criterion validity, the general ADHD and specific inattentive factors were uniquely associated with home and school impairment (R² = .13-.29) but not adolescent risk-tasking behavior. Results are discussed with respect to the ways in which bifactor models of ADHD inform the diagnostic criteria for ADHD.

Research Review: Multi-informant integration in child and adolescent psychopathology diagnosis

BACKGROUND

An empirically based, clinically usable approach to cross-informant integration in clinical assessment is needed. Although the importance of this ongoing issue is becoming increasingly recognized, little in the way of solid recommendations is currently provided to researchers and clinicians seeking to incorporate multiple informant reports in diagnosis of child psychopathology. The issue is timely because recent developments have created new opportunities for improved handling of this problem. For example, advanced theories of psychopathology and normal and abnormal child development provide theoretical guidance for how integration of multiple informants should be handled for specific disorders and at particular ages. In addition, more sophisticated data analytic approaches are now available, including advanced latent variable models, which allow for complex measurement approaches with consideration of measurement invariance.

FINDINGS

The increasing availability and mobility of computing devices suggests that it will be increasingly feasible for clinicians to implement more advanced methods rather than being confined to the easily memorized algorithms of the DSM system.

CONCLUSIONS

Development of models of cross-informant integration for individual disorders based on theory and tests of the incremental validity of more sophisticated cross-informant integration approaches in comparison to external validation criteria (e.g. longitudinal trajectories and outcomes, treatment response, and behavior genetic etiology) should be a focus of future work.

A new mouse model of ADHD for medication development

ADHD is a major societal problem with increasing incidence and a stagnant track record for treatment advances. A lack of appropriate animal models has partly contributed to the incremental advance of this field. Hence, our goal was to generate a novel mouse model that could be useful for ADHD medication development. We reasoned that hyperactivity is a core feature of ADHD that could easily be bred into a population, but to what extent other hallmark features of ADHD would appear as correlated responses was unknown. Hence, starting from a heterogeneous population, we applied within-family selection over 16 generations to produce a High-Active line, while simultaneously maintaining an unselected line to serve as the Control. We discovered that the High-Active line demonstrated motor impulsivity in two different versions of the Go/No-go test, which was ameliorated with a low dose of amphetamine, and further displayed hypoactivation of the prefrontal cortex and dysregulated cerebellar vermal activation as indexed by c-Fos immunohistochemical staining. We conclude that the High-Active line represents a valid model for the Hyperactive-Impulsive subtype of ADHD and therefore may be used in future studies to advance our understanding of the etiology of ADHD and screen novel compounds for its treatment.

Refining Diagnostic Procedures for Adults With Symptoms of ADHD

Attention deficit/hyperactivity disorder (ADHD) is a chronic disorder that afflicts individuals into adulthood. The field continues to refine diagnostic standards for ADHD in adults, complicated by the disorder's heterogeneous presentation, subjective symptoms, and overlap with other disorders. Two key diagnostic questions are from whom to collect diagnostic information and which symptoms should be contained on an adult diagnostic checklist. Using a trifactor model, Martel et al. examine these questions in a sample of adults with and without self-identified ADHD symptoms. In this response, we highlight the importance of their finding that self and informant symptom reports differ in a sample of adults who acknowledge ADHD symptoms. We also review issues that continue to face the field related to model specification, evaluating symptom utility, and sample composition, discussing how these issues influence conclusions that may be drawn from Martel et al. and similar investigations. We conclude that the article makes an important research contribution about the nature of self and informant ADHD symptom reports but emphasize that symptom checklist refinement must occur through a broad lens that considers work from a range of sample types and clinically informative analytic strategies.

Bifactor Models of Attention-Deficit/Hyperactivity Disorder (ADHD): An Evaluation of Three Necessary but Underused Psychometric Indexes

BACKGROUND

In the past decade, the bifactor model of attention-deficit/hyperactivity disorder (ADHD) has been extensively researched. This model consists of an ADHD general dimension and two specific factors: inattention and hyperactivity/impulsivity. All studies conclude that the bifactor is superior to the traditional two-correlated factors model, according to the fit obtained by factor analysis. However, the proper interpretation of a bifactor not only depends on the fit but also on the quality of the measurement model.

OBJECTIVE

To evaluate the model-based reliability, distribution of common variance and construct replicability of general and specific ADHD factors.

METHOD

We estimated expected common variance, omega hierarchical/subscale and H-index from standardized factor loadings of 31 ADHD bifactor models previously published.

RESULTS AND CONCLUSION

The ADHD general factor explained most of the common variance. Given the low reliable variance ratios, the specific factors were difficult to interpret. However, in clinical samples, inattention acquired sufficient specificity and stability for interpretation beyond the general factor. Implications for research and clinical practice are discussed.

A network analysis of developmental change in ADHD symptom structure from preschool to adulthood

Although there is substantial support for the validity of the diagnosis of ADHD, there is considerable disagreement about how to best capture developmental changes in the expression of ADHD symptomatology. The current paper examines the associations among the 18 individual ADHD symptoms using a novel network analysis approach, from preschool to adulthood. The 1,420 participants were grouped into four age brackets: Preschool (age 3-6, n = 109), childhood (age 6-12, n = 548), adolescence (age 13-17, n = 357), and young adulthood (age 18-36, n = 406). All participants completed a multi-stage, multi-informant diagnostic process, and self and informant symptom ratings were obtained. Network analysis indicated ADHD symptom structure became more differentiated over development. Two symptoms Often easily distracted and Difficulty sustaining attention appeared as central, or core, symptoms across all age groups. Thus, a small number of core symptoms may warrant extra weighting in future diagnostic systems.

Psychometrically Informed Approach to Integration of Multiple Informant Ratings in Adult ADHD in a Community-Recruited Sample

Although Diagnostic and Statistical Manual of Mental Disorders-Fifth edition requires that attention-deficit/hyperactivity disorder (ADHD) symptoms are apparent across settings, assessed by multiple informants, there remains no standardized approach to integration of multiple sources in adult ADHD diagnosis. The goal of the study was to evaluate informant effects on adult ADHD symptom ratings. Participants were 406 adults, ages 18 to 37, and identified second reporters, recruited from the community, and completing a comprehensive diagnostic and cognitive assessment, including a clinician-administered diagnostic interview and self- and other-report questionnaires of ADHD symptoms. Structural equation modeling indicated good fit for a trifactor model of ADHD, including general ADHD, specific inattention and hyperactivity-impulsivity, and self- and other-perspective factors. Yet there were a number of symptoms on the specific hyperactive-impulsive and self-factors that exhibited nonsignificant loadings. Significant differential item functioning across self-ratings and informant ratings was also noted. The external validation indices of laboratory executive function and diagnostic team-rated impairment was significantly correlated with the specific inattentive factor. While executive function was marginally significantly correlated with the other perspective factor, impairment was associated with the self-perspective factor. Overall, inattentive symptoms may be more sensitive measures of adult ADHD, and other and self-ratings may provide different information in relation to external criteria.

Factorial Validity of the ADHD Adult Symptom Rating Scale in a French Community Sample: Results From the ChiP-ARD Study

OBJECTIVE

Recent publications reported that a bifactor model better represented the underlying structure of ADHD than classical models, at least in youth. The Adult ADHD Symptoms Rating Scale (ASRS) has been translated into many languages, but a single study compared its structure in adults across Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) and International Classification of Diseases (ICD-10) classifications.

METHOD

We investigated the factor structure, reliability, and measurement invariance of the ASRS among a community sample of 1,171 adults.

RESULTS

Results support a bifactor model, including one general ADHD factor and three specific Inattention, Hyperactivity, and Impulsivity factors corresponding to ICD-10, albeit the Impulsivity specific factor was weakly defined. Results also support the complete measurement invariance of this model across gender and age groups, and that men have higher scores than women on the ADHD G-factor but lower scores on all three S-factors.

CONCLUSION

Results suggest that a total ASRS-ADHD score is meaningful, reliable, and valid in adults. (J. of Att. Dis. 2016; 20(6) 530-541).