The hierarchical factor model of ADHD: invariant across age and national groupings?

Adult attention-deficit/hyperactivity symptoms and parental cognitions: a meta-analysis

Introduction

Attention-deficit/hyperactivity disorder (ADHD) symptoms in adults interfere with parental functioning. Dysfunctional parental cognitions may play a role in this impairment. Despite the importance of parental cognitions on parents and children's outcomes, up to now, no systematic review or meta-analysis of these findings is available. To fill this gap, this meta-analysis aimed to evaluate the relationship between adult ADHD symptoms and parental cognitions.

Methods

We conducted searches in Web of Science, PubMed, and ProQuest from January 2000 to June 2023. Studies were included if they provided data on the relationship between parental ADHD symptoms and parental cognitions by means of a row correlational coefficient, or means and standard deviation were reported for each study group. A random-effects model was used. Publication bias was assessed by funnel plot and Rosenthal's fail-safe N. Moderator analyses were conducted by means of subgroup analysis and meta-regression analyses.

Results

Fifteen published papers were included (N = 2851), and 51 effect sizes were analysed. The weighted mean effect size was small but significant (Fisher's Z = 0.186, k = 15, 95% CI [0.120 - 0.252], z = 5.539, p < 0.001), indicating that ADHD symptoms in adults are associated with more negative and less positive parental cognitions. The Fail-Safe N analysis suggested a robust effect. Tweedie's trim and fill results suggested that five studies were missing; after five missing studies had been imputed, the mean overall effect size dropped to 0.116 (0.080 - 0.152). There was significant heterogeneity among effect sizes. The methodology of the study was found to be a significant moderator. Meta-regression analyses revealed that the lower age of the parent and the child were related to more negative parental cognitions.

Discussion

Though the analysis might be inflated by publication bias, our results suggest a significant association between ADHD symptom level and dysfunctional parental cognitions. Biased negative perceptions of the parental role, the child and co-parenting may play a central mediator role between parental ADHD and parent and child outcomes. Given the familiar nature of ADHD, targeting dysfunctional parental cognitions in parent training programs is warranted.

Systematic review registration

osf.io/pnur7.

Utility for Clinical Practice of a Bifactor ADHD Model in an Elementary School Population in Mexico

We assessed the appropriateness of the bifactor model for a Mexican ADHD symptom questionnaire (BMQ-ADHD) applied to parents and teachers of elementary school children. With a sample of 765 reports of children's behavior (48.7% with ADHD A1 criteria, 42.6% girls, mean age 8.5 years [± 1.6 sd]), we examined construct validity, measurement invariance, differences for gender and school level, and the appropriateness of using summed scores. The BMQ-ADHD questionnaire was characterized by good construct validity for the bifactor model for parents' and teachers' reports. For both corpora, we detected invariance for gender and school level. There were differences in ADHD symptoms by gender, but not by school year. The summed scores may represent the factors accurately for females but may present difficulty for males in the parents' questionnaires. The present study revealed good BMQ-ADHD psychometric properties for a unidimensional-hierarchical ADHD scale segregated by gender for parents' and teachers' reports.

Contributions of attentional control, hyperactivity-impulsivity, and reading skills to performance on a fourth-grade state writing test

Writing proficiency facilitates higher achievement in educational and professional endeavors, yet most students fail to meet national writing benchmarks by the end of high school. Attentional control and overall reading skill are documented to result in better writing quality; however, most research on these relationships has focused on early elementary students (K-3rd grade. This project evaluated the relationship between attentional control, hyperactivity-impulsivity, word reading, and reading comprehension to overall writing performance on a high-stakes writing test. Participants included 266 fourth-grade struggling readers who completed the Strengths and Weaknesses of ADHD Symptoms and Normal Behavior (SWAN; Swanson et al., 2001, 2012) for attentional control and hyperactivity-impulsivity, the Woodcock-Johnson III (WJ-III; Woodcock et al., 2001) Letter-Word Identification test for word reading, the WJ-III Passage Comprehension test for reading comprehension, and the State of Texas Assessments of Academic Readiness (STAAR) writing test for overall writing. Hyperactivity-impulsivity was not related to word reading (β = 0.02, p > .05), reading comprehension (β = 0.06, p > .05), or writing (β = 0.14, p > .05), whereas attentional control (β = 0.51, p < .01) and reading comprehension (β = 0.55, p < .001) contributed to overall writing. Reading comprehension (β = 0.55, p < .01) had a greater impact on writing than word reading (β = 0.13, p > .05), which suggests that as academic rigor increases in the upper elementary school grades (4th grade and higher), basic skills are less predictive of success on complex tasks such as writing. Implications for increasing writing proficiency through research and practice are discussed.

Characterizing the ASD-ADHD phenotype: measurement structure and invariance in a clinical sample

BACKGROUND

Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) have considerable overlap, supporting the need for a dimensional framework that examines neurodevelopmental domains which cross traditional diagnostic boundaries. In the following study, we use factor analysis to deconstruct the ASD-ADHD phenotype into its underlying phenotypic domains and test for measurement invariance across adaptive functioning, age, gender and ASD/ADHD clinical diagnoses.

METHODS

Participants included children and youth (aged 3-20 years) with a clinical diagnosis of ASD (n = 727) or ADHD (n = 770) for a total of 1,497 participants. Parents of these children completed the Social Communication Questionnaire (SCQ), a measure of autism symptoms, and the Strengths and Weaknesses of ADHD and Normal Behaviour (SWAN) questionnaire, a measure of ADHD symptoms. An exploratory factor analysis (EFA) was performed on combined SCQ and SWAN items. This was followed by a confirmatory factor analysis (CFA) and tests of measurement invariance.

RESULTS

EFA revealed a four-factor solution (inattention, hyperactivity/impulsivity, social-communication, and restricted, repetitive, behaviours and interests (RRBI)) and a CFA confirmed good model fit. This solution also showed good model fit across subgroups of interest.

CONCLUSIONS

Our study shows that a combined ASD-ADHD phenotype is characterized by two latent ASD domains (social communication and RRBIs) and two latent ADHD domains (inattention and hyperactivity/impulsivity). We established measurement invariance of the derived measurement model across adaptive functioning, age, gender and ASD/ADHD diagnoses.

Studying hot executive function in infancy: Insights from research on emotional development

Recent calls have urged to bridge the fields of emotional and cognitive development to advance theoretical and empirical pursuits. Yet, despite notable overlap between research on executive function and emotion regulation, a uniting theory that informs future avenues of research is lacking. Infants are known to lack emotion regulation skills, as they are developing the abilities to regulate their emotions and coordinated responses. However, the field of emotional development demonstrates that at an early age, infants are adept at regulating their behaviors in response to others emotional reactions. Moreover, although classic delay of gratification tasks are fairly ecological measures, rarely are rules expressed to infants without emotions. This paper draws from recent interest in hot executive function to link infancy research on executive function and emotion. Hot executive function lends itself as a useful construct in this endeavor because it unites the study emotion and executive function. We offer a perspective that refines hot executive function within prominent emotion theories while discussing infant executive function and emotion empirical pursuits. Our perspective presents reliable paradigms from the field of emotional development to serve as tools for studying the development of hot executive function.

The Effects of Innovation Adoption and Social Factors between Sustainable Supply Chain Management Practices and Sustainable Firm Performance: A Moderated Mediation Model

The aim of this study was to develop higher-order scales for assessing sustainable supply chain management practices, innovation adoption, and sustainable firm performance in the restaurant sector. Three different higher-order scales were developed for assessing the SSCM, SFP and innovation adoption. The first scale for SSCM higher-order construct consisted of service–product supply chain management practices (SPSSCM), service–setting supply chain management practices (SSSSCM), and service–delivery supply chain management practices (SDSSCM). The second higher-order scale for sustainable firm performance (SFP) consisted of economic, operational, environmental, and socio-cultural performance. The third higher-order scale for innovation adoption (INNO) consisted of “product- and process-based innovation”, “marketing-based innovation”, “technology-based innovation” and “organizational innovation”. The face, content, construct, convergent, and discriminant validity was tested using pilot study, expert opinion, EFA, and CFA. With 178 responses collected from restaurateurs, managers, and supervisors of casual restaurants in Prachuap Khiri Khan province in Thailand, this study evaluates the direct effects of SSCM on SFP. It further evaluates the mediating role of innovation adoption between sustainable supply chain management practices and firm performance and the moderated mediation effects of socio-demographic factors such as age, gender, education, and experience. The results reveal that sustainable supply chain management practices can positively lead to sustainable firm performance. However, irrespective of the indirect effects of socio-demographic factors, adopting innovation completely mediates the relationship between sustainable supply chain management practices and firm performance.

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.

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.

Reliability and Validity of the Chen ADHD Scale (C-ADHDS)

PURPOSE

This study aimed to establish the Chen ADHD Scale and to examine its reliability and validity.

PATIENTS AND METHODS

We recruited 114 individuals diagnosed with attention-deficit/hyperactivity disorder (ADHD) and 39 non-ADHD controls aged between 5 and 18 years. Their parents completed the Chen ADHD Scale, Chinese versions of the SNAP-IV, and Strengths and Difficulties Questionnaire (SDQ). We examined the psychometric properties of Chen ADHD Scale, including test-retest reliability, internal consistency, construct validity, convergent and divergent validity.

RESULTS

Receiver operating characteristic analysis was performed to calculate the area under the curve (AUC), sensitivity, and specificity of the Chen ADHD Scale for predicting ADHD. The Chen ADHD Scale demonstrated satisfactory test-retest reliability (intraclass correlation = 0.916), internal consistency (alpha = 0.966 to 0.978), a good model fit for a two-factor structure (inattention and hyperactivity-impulsivity) and good convergent and divergent validity with SNAP-IV and SDQ. The AUC of Chen ADHD Scale for predicting ADHD was 0.944. The optimal cut-off value of Chen ADHD Scale with impairment requirement for predicting ADHD was 37 with a sensitivity of 0.87 and a specificity of 0.97.

CONCLUSION

The Chen ADHD Scale is a reliable and valid instrument for screening ADHD symptoms in clinical settings in Taiwan.

ADHD Symptoms in Adolescents' Everyday Life: Fluctuations and Symptom Structure Within and Between Individuals

Objective: This study investigated whether self-reported ADHD symptoms fluctuate substantially within adolescents from day to day, and examined the underlying symptom factor structure on a within- and between-person level. Method: Adolescents (N = 166) rated their ADHD symptoms over the phone on eight consecutive evenings (total ratings: n = 1,264). Results: ADHD symptoms showed substantial fluctuations within adolescents from day to day, as indicated by within-person standard deviations and intraclass correlation coefficients. Both a two-level factor model with three correlated factors (inattention, hyperactivity, impulsivity) and a two-level bifactor model with a general ADHD symptom factor and a specific inattention factor provided acceptable to good accounts of the structure underlying daily ADHD symptom ratings on the between- and the within-person level. Conclusion: The study demonstrates that adolescents' ADHD symptoms fluctuate from day to day and highlights the need for intensive diagnostic processes with repeated symptom assessments and interventions that address symptom fluctuations.

Invariance of ADHD Symptoms Across Sex and Age: a Latent Analysis of ADHD and Impairment Ratings from Early Childhood into Adolescence

A population-based longitudinal sample of 489 twin pairs was assessed at six time points over ten years to examine the measurement invariance and stability of attention-deficit/hyperactivity disorder (ADHD) symptoms, as well as the developmental relations between inattention (IN), hyperactivity-impulsivity (HI), and multiple aspects of functional impairment. Parent ratings of ADHD symptoms and functional impairment were obtained in preschool and after the completion of kindergarten, first, second, fourth, and ninth grades. Results of the temporal and sex invariance models indicated that parent ratings of the 18 ADHD symptoms function in the same manner for females and males from early childhood into adolescence. In addition to establishing this prerequisite condition for the interpretation of longitudinal and between-sex differences in the IN and HI symptom dimensions, cross-lagged models indicated that both IN and HI were associated with increased risk for both concurrent and future overall, social, and recreational impairment, whereas only IN was uniquely associated with later academic impairment. Taken together, the current results demonstrate that IN and HI are highly stable from preschool through ninth grade, invariant between females and males, and indicative of risk for impairment in multiple areas, thereby providing strong support for the validity of the symptom dimensions among both sexes.

Moderation of parenting by inhibitory control in the prediction of the common and unique variance of hyperactivity-impulsivity and inattention

This study examined whether the interaction between parenting and inhibitory control predicts hyperactivity-impulsivity and inattention in 195 children. Observation data of positive parenting were collected at 4 years, and mother reports of coercive parenting at 5 years, inhibitory control at 6 years, and hyperactivity-impulsivity/inattention at 7 years were obtained. The common and unique variance of hyperactivity-impulsivity and inattention symptoms were examined as outcomes using a bifactor model. Results indicated that positive parenting practices predicted lower levels of hyperactivity-impulsivity/inattention behaviors at age 7 only when children's inhibitory control was high. These results support the vantage sensitivity model, which posits that some individuals show an increased sensitivity to positive experiences exclusively, and support the appropriateness of a targeted prevention approach in early childhood.

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.

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.

A Multilevel Bifactor Approach to Construct Validation of Mixed-Format Scales

Wording effects associated with positively and negatively worded items have been found in many scales. Such effects may threaten construct validity and introduce systematic bias in the interpretation of results. A variety of models have been applied to address wording effects, such as the correlated uniqueness model and the correlated traits and correlated methods model. This study presents the multilevel bifactor approach to handling wording effects of mixed-format scales used in a multilevel context. The Students Confident in Mathematics scale is used to illustrate this approach. Results from comparing a series of models showed that positive and negative wording effects were present at both the within and the between levels. When the wording effects were ignored, the within-level predictive validity of the Students Confident in Mathematics scale was close to that under the multilevel bifactor model. However, at the between level, a lower validity coefficient was observed when ignoring the wording effects. Implications for applied researchers are discussed.

The internal structure of foster-parent completed SDQ for school-aged children

Mental health problems are common in foster-children, and tools to measure the mental health of these children are needed. One candidate instrument is the Strengths and Difficulties Questionnaire (SDQ), a measure of child psychological adjustment that is increasingly being employed by Child Protection services. The aim of the current study was to examine the structural validity of the foster parent completed SDQ in a sample of 237 school aged foster children. Confirmatory factor analysis demonstrated an excellent fit of the foster parent completed SDQ data to a five-factor model (CFI = 0.96, RMSEA = 0.05, 90% CI [0.04, 0.06]), thus confirming the structural validity of the five-factor model for the parent-version of the SDQ in Norwegian foster children. Measurement invariance analyses indicated that boys had lower thresholds for fighting with or bullying other children than girls. Girls were on their side more likely to be rated as less popular than boys with a similar level of peer problems.

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.

Comorbidity of Alcohol and Gambling Problems in Emerging Adults: A Bifactor Model Conceptualization

Addictive disorders, such as pathological gambling and alcohol use disorders, frequently co-occur at greater than chance levels. Substantive questions stem from this comorbidity regarding the extent to which shared variance between gambling and alcohol use reflects a psychological core of addictive tendencies, and whether this differs as a function of gender. The aims of this study were to differentiate both common and unique variance in alcohol and gambling problems in a bifactor model, examine measurement invariance of this model by gender, and identify substantive correlates of the final bifactor model. Undergraduates (N = 4475) from a large northwestern university completed an online screening questionnaire which included demographics, quantity of money lost and won when gambling, the South Oaks Gambling Screen, the AUDIT, gambling motives, drinking motives, personality, and the Brief Symptom Inventory. Results suggest that the bifactor model fit the data well in the full sample. Although the data suggest configural invariance across gender, factor loadings could not be constrained to be equal between men and women. As such, general and specific factors were examined separately by gender with a more intensive subsample of females and males (n = 264). Correlations with motivational tendencies, personality traits, and mental health symptoms indicated support for the validity of the bifactor model, as well as gender-specific patterns of association. Results suggest informative distinctions between shared and unique attributes related to problematic drinking and gambling.

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.

A hierarchical causal taxonomy of psychopathology across the life span

We propose a taxonomy of psychopathology based on patterns of shared causal influences identified in a review of multivariate behavior genetic studies that distinguish genetic and environmental influences that are either common to multiple dimensions of psychopathology or unique to each dimension. At the phenotypic level, first-order dimensions are defined by correlations among symptoms; correlations among first-order dimensions similarly define higher-order domains (e.g., internalizing or externalizing psychopathology). We hypothesize that the robust phenotypic correlations among first-order dimensions reflect a hierarchy of increasingly specific etiologic influences. Some nonspecific etiologic factors increase risk for all first-order dimensions of psychopathology to varying degrees through a general factor of psychopathology. Other nonspecific etiologic factors increase risk only for all first-order dimensions within a more specific higher-order domain. Furthermore, each first-order dimension has its own unique causal influences. Genetic and environmental influences common to family members tend to be nonspecific, whereas environmental influences unique to each individual are more dimension-specific. We posit that these causal influences on psychopathology are moderated by sex and developmental processes. This causal taxonomy also provides a novel framework for understanding the heterogeneity of each first-order dimension: Different persons exhibiting similar symptoms may be influenced by different combinations of etiologic influences from each of the 3 levels of the etiologic hierarchy. Furthermore, we relate the proposed causal taxonomy to transdimensional psychobiological processes, which also impact the heterogeneity of each psychopathology dimension. This causal taxonomy implies the need for changes in strategies for studying the etiology, psychobiology, prevention, and treatment of psychopathology. (PsycINFO Database Record

Prenatal Alcohol Exposure in Rodents As a Promising Model for the Study of ADHD Molecular Basis

A physiological parallelism, or even a causal effect relationship, can be deducted from the analysis of the main characteristics of the “Alcohol Related Neurodevelopmental Disorders” (ARND), derived from prenatal alcohol exposure (PAE), and the behavioral performance in the Attention-deficit/hyperactivity disorder (ADHD). These two clinically distinct disease entities, exhibits many common features. They affect neurological shared pathways, and also related neurotransmitter systems. We briefly review here these parallelisms, with their common and uncommon characteristics, and with an emphasis in the subjacent molecular mechanisms of the behavioral manifestations, that lead us to propose that PAE in rats can be considered as a suitable model for the study of ADHD.

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.

Attention-deficit/hyperactivity disorder and sluggish cognitive tempo throughout childhood: temporal invariance and stability from preschool through ninth grade

BACKGROUND

Although multiple cross-sectional studies have shown symptoms of sluggish cognitive tempo (SCT) and attention-deficit/hyperactivity disorder (ADHD) to be statistically distinct, studies have yet to examine the temporal stability and measurement invariance of SCT in a longitudinal sample. To date, only six studies have assessed SCT longitudinally, with the longest study examining SCT over a 2-year period. The overall goals of this study were to assess the 10-year longitudinal stability and interfactor relationships of ADHD and SCT symptoms among a community sample of children.

METHODS

Confirmatory factor analysis was used to assess the temporal invariance of ADHD and SCT symptoms in a large population-based longitudinal sample (International Longitudinal Twin Study of Early Reading Development) that included children assessed at preschool and after kindergarten, first, second, fourth, and ninth grades (n = 489). Latent autoregressive models were then estimated to assess the stability of these constructs.

RESULTS

Results demonstrated invariance of item loadings and intercepts from preschool through ninth grades, as well as invariance of interfactor correlations. Results further indicated that both ADHD and SCT are highly stable across these years of development, that these symptom dimensions are related but also separable, and that hyperactivity/impulsivity and SCT are both more strongly correlated with inattention than with each other and show differential developmental trajectories. Specifically, even in the presence of latent simplex analyses providing support for the developmental stability of these dimensions, linear comparisons indicated that that mean levels of hyperactivity/impulsivity decreased with time, inattentive ratings were generally stable, and SCT tended to increase slightly across development.

CONCLUSIONS

This study adds to the current literature by being the first to systematically assess and demonstrate the temporal invariance and stability of ADHD and SCT across a span of 10 years.

The Relationship Between Life Satisfaction and ADHD Symptoms in Middle School Students: Using a Bifactor Model

OBJECTIVE

ADHD is associated with increased academic and social difficulties and comorbid psychopathology which may lead to decreased life satisfaction (LS).

METHODS

The current study utilized a bifactor model of ADHD consisting of a general factor and two specific factors (inattention and hyperactivity-impulsivity) to determine if ADHD symptoms place middle school students (n= 183) at risk for diminished LS and if this relationship differed depending on whether teachers versus students reported ADHD symptoms.

RESULTS

Confirmatory factor analyses indicated that the bifactor model provided very good fit to the ADHD symptoms reported by students (comparative fit index [CFI] = .995; root mean square error of approximation [RMSEA] = .028) and teachers (CFI = .997; RMSEA = .043). Results also demonstrated that when students rated ADHD symptoms, the general ADHD factor and inattention were negatively related to LS; however, when teachers rated ADHD symptoms, only inattention was negatively related to LS.

CONCLUSIONS

Implications and future directions related to these results are discussed.

Teacher Ratings of the ADHD-RS IV in a Community Sample: Results From the ChiP-ARD Study

OBJECTIVE

Validated instruments to assess ADHD are still unavailable in many languages other than English for teachers, which constitutes a clear obstacle to screening, diagnosis, and treatment of ADHD in many European countries.

METHOD

Teachers rated 892 youths using the ADHD Rating Scale (ADHD-RS). We investigated the factor structure, reliability, and measurement invariance based on confirmatory factor analyses.

RESULTS

Results support a bifactor model, including one general ADHD factor and two specific Inattention and Hyperactivity-Impulsivity factors. But the latter is improperly defined calling into question the existence of a Predominantly Hyperactivity-Impulsivity subtype. The measurement invariance is fully supported across gender, age groups, and Gender × Age Groups.

CONCLUSION

Results support the multiple-pathways hypothesis and suggest that a total ADHD score is meaningful, reliable, and valid, as well as specific assessments of Inattention. Some youths--especially older ones--may present a profile of ADHD particularly marked by Inattention symptoms.

Relationships of Attention and Executive Functions to Oral Language, Reading, and Writing Skills and Systems in Middle Childhood and Early Adolescence

Relationships between attention/executive functions and language learning were investigated in students in Grades 4 to 9 ( N = 88) with and without specific learning disabilities (SLDs) in multiword syntax in oral and written language (OWL LD), word reading and spelling (dyslexia), and subword letter writing (dysgraphia). Prior attention-deficit/hyperactivity disorder (ADHD) diagnosis was correlated only with impaired handwriting. Parental ratings of inattention, but not hyperactivity, correlated with measures of written language but not oral language. Sustaining switching attention correlated with writing the alphabet from memory in manuscript or by keyboard and fast copying of a sentence with all the letters of the alphabet. Multiple regressions based on a principal component for composites of multiple levels of language (subword, word, and syntax/text) showed that measures of attention and executive function involving language processing rather than ratings of attention and executive function not specifically related to language accounted for more variance and identified more unique predictors in the composite outcomes for oral language, reading, and writing systems. Inhibition related to focused attention uniquely predicted outcomes for the oral language system. Findings are discussed in reference to implications for assessing and teaching students who are still learning to pay attention to heard and written language and self-regulate their language learning during middle childhood and adolescence.

Attention-deficit/hyperactivity disorder dimensionality: the reliable 'g' and the elusive 's' dimensions

The best structural model for attention-deficit/hyperactivity disorder (ADHD) symptoms remains a matter of debate. The objective of this study is to test the fit and factor reliability of competing models of the dimensional structure of ADHD symptoms in a sample of randomly selected and high-risk children and pre-adolescents from Brazil. Our sample comprised 2512 children aged 6-12 years from 57 schools in Brazil. The ADHD symptoms were assessed using parent report on the development and well-being assessment (DAWBA). Fit indexes from confirmatory factor analysis were used to test unidimensional, correlated, and bifactor models of ADHD, the latter including "g" ADHD and "s" symptom domain factors. Reliability of all models was measured with omega coefficients. A bifactor model with one general factor and three specific factors (inattention, hyperactivity, impulsivity) exhibited the best fit to the data, according to fit indices, as well as the most consistent factor loadings. However, based on omega reliability statistics, the specific inattention, hyperactivity, and impulsivity dimensions provided very little reliable information after accounting for the reliable general ADHD factor. Our study presents some psychometric evidence that ADHD specific ("s") factors might be unreliable after taking common ("g" factor) variance into account. These results are in accordance with the lack of longitudinal stability among subtypes, the absence of dimension-specific molecular genetic findings and non-specific effects of treatment strategies. Therefore, researchers and clinicians might most effectively rely on the "g" ADHD to characterize ADHD dimensional phenotype, based on currently available symptom items.

Bifactor Models Show a Superior Model Fit: Examination of the Factorial Validity of Parent-Reported and Self-Reported Symptoms of Attention-Deficit/Hyperactivity Disorders in Children and Adolescents

BACKGROUND

Various studies have demonstrated that bifactor models yield better solutions than models with correlated factors. However, the kind of bifactor model that is most appropriate is yet to be examined. The current study is the first to test bifactor models across the full age range (11-18 years) of adolescents using self-reports, and the first to test bifactor models with German subjects and German questionnaires.

SAMPLING AND METHODS

The study sample included children and adolescents aged between 6 and 18 years recruited from a German clinical sample (n = 1,081) and a German community sample (n = 642). To examine the factorial validity, we compared unidimensional, correlated factors and higher-order and bifactor models and further tested a modified incomplete bifactor model for measurement invariance.

RESULTS

Bifactor models displayed superior model fit statistics compared to correlated factor models or second-order models. However, a more parsimonious incomplete bifactor model with only 2 specific factors (inattention and impulsivity) showed a good model fit and a better factor structure than the other bifactor models. Scalar measurement invariance was given in most group comparisons.

CONCLUSION

An incomplete bifactor model would suggest that the specific inattention and impulsivity factors represent entities separable from the general attention-deficit/hyperactivity disorder construct and might, therefore, give way to a new approach to subtyping of children beyond and above attention-deficit/hyperactivity disorder.

Applying Bifactor Statistical Indices in the Evaluation of Psychological Measures

The purpose of this study was to apply a set of rarely reported psychometric indices that, nevertheless, are important to consider when evaluating psychological measures. All can be derived from a standardized loading matrix in a confirmatory bifactor model: omega reliability coefficients, factor determinacy, construct replicability, explained common variance, and percentage of uncontaminated correlations. We calculated these indices and extended the findings of 50 recent bifactor model estimation studies published in psychopathology, personality, and assessment journals. These bifactor derived indices (most not presented in the articles) provided a clearer and more complete picture of the psychometric properties of the assessment instruments. We reached 2 firm conclusions. First, although all measures had been tagged "multidimensional," unit-weighted total scores overwhelmingly reflected variance due to a single latent variable. Second, unit-weighted subscale scores often have ambiguous interpretations because their variance mostly reflects the general, not the specific, trait. Finally, we review the implications of our evaluations and consider the limits of inferences drawn from a bifactor modeling approach.

Item Response Theory Analysis of ADHD Symptoms in Children With and Without ADHD

Item response theory (IRT) was separately applied to parent- and teacher-rated symptoms of attention-deficit/hyperactivity disorder (ADHD) from a pooled sample of 526 six- to twelve-year-old children with and without ADHD. The dimensional structure ADHD was first examined using confirmatory factor analyses, including the bifactor model. A general ADHD factor and two group factors, representing inattentive and hyperactive/impulsive dimensions, optimally fit the data. Using the graded response model, we estimated discrimination and location parameters and information functions for all 18 symptoms of ADHD. Parent- and teacher-rated symptoms demonstrated adequate discrimination and location values, although these estimates varied substantially. For parent ratings, the test information curve peaked between -2 and +2 SD, suggesting that ADHD symptoms exhibited excellent overall reliability at measuring children in the low to moderate range of the general ADHD factor, but not in the extreme ranges. Similar results emerged for teacher ratings, in which the peak range of measurement precision was from -1.40 to 1.90 SD Several symptoms were comparatively more informative than others; for example, is often easily distracted ("Distracted") was the most informative parent- and teacher-rated symptom across the latent trait continuum. Clinical implications for the assessment of ADHD as well as relevant considerations for future revisions to diagnostic criteria are discussed.

Common prefrontal cortical gene expression profiles between adolescent SHR/NCrl and WKY/NCrl rats which showed inattention behavior

Factor analyses of attention-deficit/hyperactivity (ADHD) symptoms divide the behavioral symptoms of ADHD into two separate domains, one reflecting inattention and the other, a combination of hyperactivity and impulsivity. Identifying domain-specific genetic risk variants may aid in the discovery of specific biological risk factors for ADHD. In contrast with data available on genes involved in hyperactivity and impulsivity, there is limited information on the genetic influences of inattention. Transcriptional profiling analysis in animal models of disorders may provide an important tool to identify genetic involvement in behavioral phenotypes. To explore some of the potential genetic underpinnings of ADHD inattention, we examined common differentially expressed genes (DEGs) in the prefrontal cortex of SHR/NCrl, the most validated animal model of ADHD and WKY/NCrl, animal model of ADHD-inattentive type. In contrast with Wistar rats, strain representing the "normal" heterogeneous population, SHR/NCrl and WKY/NCrl showed inattention behavior in the Y-maze task. The common DEGs in the PFC of SHR/NCrl and WKY/NCrl vs. Wistar rats are those involved in transcription (e.g. Creg1, Thrsp, Zeb2), synaptic transmission (e.g. Atp2b2, Syt12, Chrna5), neurological system process (e.g. Atg7, Cacnb4, Grin3a), and immune response (e.g. Atg7, Ip6k2, Mx2). qRT-PCR analyses validated expression patterns of genes representing the major functional gene families among the DEGs (Grin3a, Thrsp, Vof-16 and Zeb2). Although further studies are warranted, the present findings indicate novel genes associated with known functional pathways of relevance to ADHD which are assumed to play important roles in the etiology of ADHD-inattentive subtype.

Long-term course of ADHD symptoms from childhood to early adulthood in a community sample

Comparatively little information is available from population-based studies on subgroup trajectories of attention-deficit/hyperactivity disorder (ADHD) core symptoms of inattention and hyperactivity-impulsivity (particularly as defined by DSM-IV and ICD-10). Recent report of a subgroup with high and increasing inattention symptoms across development requires replication. To identify the different trajectory subgroups for inattention, hyperactivity-impulsivity and total symptoms of ADHD in children and adolescents aged 7-19 years. Eleven birth cohorts from 2,593 families with children and adolescents who had parent ratings for the outcome measures of inattention, hyperactivity-impulsivity or total symptoms were considered. Data were analysed using an accelerated longitudinal design and growth mixture modelling was applied to detect subgroups. For all three outcome measures, three trajectories with low (78.3-83.3 %), moderate (13.4-18.8 %) and high (2.8-3.2 %) symptom levels were detected. Course within these subgroups was largely comparable across outcome domains. In general, a decrease in symptoms with age was observed in all severity subgroups, although the developmental course was stable for the high subgroups of inattention and total symptoms. About 3 % of children in a community-based sample follow a course with a high level of ADHD symptoms. In this high trajectory group, hyperactivity-impulsivity symptoms decrease with age from 7 to 19 years, whilst inattention and total symptoms are stable. There was no evidence for an increase in symptoms across childhood/adolescence in any of the severity groups.

Using factor analytic models to examine the association between attention-deficit/hyperactivity disorder symptoms and health-related outcomes in a representative population survey

The objective of the study was to examine the factor structure of attention-deficit/hyperactivity disorder (ADHD) symptoms in a representative population survey of adults and the association of these factors with health outcomes. Hierarchical and correlated factor analysis models were compared, and regression analyses with these models were used to determine the associations with psychological distress and substance use problems. A total of 1449 adults 18-65 years of age participated in a cross-sectional survey over the phone. ADHD symptom data came from an ADHD screener (10 items), and health outcomes were assessed using a questionnaire measuring psychological distress and two measures of substance use problems. The hierarchical general factor models with specific factors best represented the structure of ADHD in this representative population survey. The general factor and residual inattention factor were significantly associated with psychological distress, and the general factor was associated with substance use problems. From the correlated factor models, the inattention factor was associated with psychological distress and the hyperactivity factor was related to substance use problems. The hierarchical and correlated factor models explained similar levels of variance in outcomes. The results replicate previous studies indicating that a model of ADHD symptoms with a unitary dimension and separable dimensions of residual inattention and hyperactivity/impulsivity demonstrates a better fit than correlated factor models. The ADHD general factor was consistently significantly related to outcomes.

ADHD in DSM-5: a field trial in a large, representative sample of 18- to 19-year-old adults

BACKGROUND

The DSM criteria for adult attention-deficit/hyperactivity disorder (ADHD) have not been tested in American Psychiatric Association (APA) field trials for either DSM-IV or DSM-5. This study aimed to assess: (a) the prevalence of ADHD according to DSM-5 criteria; (b) the factor solution that provides the best fit for ADHD symptoms; (c) the symptoms with the highest predictive value for clinical impairment; and (d) the best symptomatic threshold for each ADHD dimension (inattention and hyperactivity/impulsivity).

METHOD

Trained psychologists evaluated 4000 young adults from the 1993 Pelotas Birth Cohort Study with an instrument covering all DSM-5 ADHD criteria. A series of confirmatory factor analyses (CFAs) tested the best factor structure. Complex logistic regressions assessed differential contributions of each symptom to clinical impairment. Receiver-operating characteristic (ROC) analyses tested which would be the best symptomatic cut-off in the number of symptoms for predicting impairment.

RESULTS

The prevalence of DSM-5 ADHD was 3.55% [95% confidence interval (CI) 2.98-4.12]. The estimated prevalence of DSM-IV ADHD was 2.8%. CFA revealed that a bifactor model with a single general factor and two specific factors provided the best fit for DSM-5 symptoms. Inattentive symptoms continued to be the most important predictors of impairment in adults. The best cut-offs were five symptoms of inattention and four symptoms of hyperactivity/impulsivity.

CONCLUSIONS

Our results, combined with previous findings, suggest a 27% increase in the expected prevalence of ADHD among young adults, comparing DSM-IV to DSM-5 criteria. The DSM-5 symptomatic organization derived a similar factor structure for adults as DSM-IV symptoms. Data using DSM-5 criteria support lowering the symptomatic threshold for diagnosing ADHD in adults.

Hyperactivity and Motoric Activity in ADHD: Characterization, Assessment, and Intervention

The aim of the present literature review is threefold. (1) We will review theories, models, and studies on symptomatic hyperactivity and motoric activity in attention-deficit/hyperactivity disorder (ADHD). (2) Another focus will be on assessment methods that have been proven to be effective in the detection of hyperactivity and motoric activity in children, adolescents, and adults with and without ADHD and emerging areas of research in the field of ADHD. We will compare subjective methods (i.e., rating scales) and objective methods (i.e., accelerometers). (3) Finally, physical activity intervention studies aiming at a modification of activity and overactive behavior will be summarized that seem to be promising candidates for alleviating hyperactivity symptoms in children, adolescents, and adults with ADHD.

ADHD inattentive symptoms mediate the relationship between intelligence and academic performance in children aged 6-14

OBJECTIVE

Fluid intelligence and the behavioral problems of attention-deficit/hyperactivity disorder (ADHD) are related to academic performance, but how this association occurs is unclear. This study aimed to assess mediation and moderation models that test possible pathways of influence between these factors.

METHODS

Sixty-two children with ADHD and 33 age-matched, typically developing students were evaluated with Raven's Colored Progressive Matrices and the spelling and arithmetic subtests of the Brazilian School Achievement Test. Dimensional ADHD symptomatology was reported by parents.

RESULTS

Our findings suggest that fluid intelligence has a significant impact on academic tests through inattention. The inattentive dimension was the principal behavioral source of influence, also accounting for the association of hyperactive-impulsive manifestations with school achievement. This cognitive-to-behavioral influence path seems to be independent of diagnosis related group, and gender, but lower socioeconomic status might increase its strength.

CONCLUSION

Fluid intelligence is a relevant factor in the influence of ADHD behavioral symptoms on academic performance, but its impact is indirect. Therefore, early identification of both fluid intelligence and inattentive symptoms is of the utmost importance to prevent impaired academic performance and future difficulties in functioning.

I can't get no satisfaction: potential causes of boredom

A variety of causes of boredom have been proposed including environmental, motivational, emotional, and cognitive factors. Here, we explore four potential cognitive causes of boredom: inattention, hyperactivity, impulsivity, and executive dysfunction. Specifically, we examine the unique and common associations between these factors and boredom propensity. Recent research has established that the two most commonly used measures of boredom propensity (BPS and BSS) are not measuring the same underlying construct. Thus, a second goal of the present project is to determine the unique and common roles of inattention, hyperactivity, impulsivity and poor executive system functioning in predicting the BPS and BSS specifically. The findings reveal that inattention, hyperactivity and executive dysfunction predict boredom propensity, with shared variance accounting for the greater part of this effect. Further, executive dysfunction and hyperactivity uniquely predict boredom propensity as measured by the BPS and BSS, respectively.

Bifactor latent structure of ADHD/ODD symptoms: predictions of dual-pathway/trait-impulsivity etiological models of ADHD

OBJECTIVE

To determine if ADHD/ODD symptoms are better represented by a bifactor model of disruptive behavior [general disruptive behavior factor along with specific inattention (IN), specific hyperactivity/impulsivity (HI), and specific oppositional defiant disorder (ODD) factors] than an ADHD-IN, ADHD-HI, and ODD three-factor model.

METHOD

Mothers' and fathers' ratings of ADHD-IN, ADHD-HI, and ODD symptoms in a community sample of 4,658 children and adolescents (53% female) from Brazil, Thailand, and the US were used to evaluate the measurement models.

RESULTS

The bifactor model of disruptive behavior provided a better fit than the three factor model. The bifactor model also occurred with mothers' and fathers' ratings of male and female children and adolescents.

CONCLUSIONS

Consistent with predictions derived from recently articulated dual-pathway and trait-impulsivity models of externalizing liability, and from behavioral genetics studies indicating near complete overlap in vulnerability to ADHD and ODD, ADHD and ODD symptoms arose from a single, general disruptive behavior factor, which accounted for all of the variance in HI subscale scores and over half of the variance IN and ODD subscales. Thus, IN, HI, and ODD subscale scores strongly reflect a general disruptive behavior factor – not the specific content of their respective constructs.

Evidence-based guidelines for the pharmacological management of attention deficit hyperactivity disorder: update on recommendations from the British Association for Psychopharmacology

Attention deficit hyperactivity disorder (ADHD) is a common condition with a high societal burden. The present guidelines summarise current literature, generating expert consensus recommendations for the treatment of ADHD in children and adults. These guidelines also provide a review of recent research in the fields of neuroimaging, neuropsychology and genetics of ADHD. Novel discoveries in these areas have informed physiological models for the disease. Since the publication of the previous British Association for Psychopharmacology guidelines in 2008, new drugs have been licensed and further compounds are being investigated. The publication of randomised controlled trials of psychological interventions has contributed to the range of treatment options for ADHD. As the disorder has been diagnosed more frequently there has been greater focus on comorbid conditions and how they impact treatment. Services have continued to develop for the treatment of ADHD in adults and care agreements have been introduced to facilitate access to treatment.

Genetic associations between the symptoms of attention-deficit/hyperactivity disorder and emotional lability in child and adolescent twins

OBJECTIVE

Emotional lability is recognized as an associated feature of attention-deficit/hyperactivity disorder (ADHD). However, the degree of phenotypic and etiologic overlap between emotional lability and the ADHD dimensions of hyperactivity-impulsivity and inattention remains unclear. The present study examines these associations in a large, community twin sample.

METHOD

Structural equation models were fit to data from 1,920 child and adolescent twin pairs (age range, 5-18 years). Symptoms of hyperactivity-impulsivity (HI) and inattention (IA) were assessed using a modified version of the DuPaul rating scale, completed by parents. Symptoms of emotional lability (EL) were assessed using the parent-rated Conners 10-item scale.

RESULTS

There were moderate to strong phenotypic correlations between HI, IA, and EL. Multivariate twin modeling revealed that a common pathway model best accounted for the covariance among these dimensions, represented by a highly heritable latent factor. Ad hoc analyses confirmed that all additive genetic influences on HI, IA, and EL were shared, and identified a significantly stronger association of EL with the latent ADHD factor in older than in younger individuals.

CONCLUSIONS

Emotional lability was phenotypically and genetically associated with hyperactivity-impulsivity and inattention in children and adolescents. The finding that a single, heritable, latent factor accounted for covariation among these phenotypes indicates that their co-occurrence is primarily the result of overlapping genetic effects. These data support the hypothesis that emotional lability is etiologically relevant to the core ADHD phenotype, and that it should be targeted in assessment and treatment in clinical practice.

Replication and external validation of a bi-factor parameterization of attention deficit/hyperactivity symptomatology

This study evaluated the fit and criterion validity of a recently proposed bi-factor structure for attention deficit/hyperactivity disorder (ADHD) symptoms. Participants were 1,093 children, drawn from an ongoing prospective longitudinal study, whose ADHD symptoms were rated by parents and teachers when children were in 1st grade. The criterion validity of the bi-factor model was established using a range of school-based outcomes that included treatment utilization, teacher perceptions of the need for treatment, academic functioning, and peer and teacher relationship quality. Results indicated that a bi-factor model parameterization provided an equally good fit to parent, teacher, and combined reports of ADHD symptoms as did traditional 1-, 2-, and 3-factor models. However, in contrast to traditional models, the bi-factor parameterization acknowledged both the unity and diversity of ADHD symptoms. The general ADHD latent factor explained the vast majority of the observed variation in every symptom. Whereas the general ADHD latent factor was significantly associated with all 15 outcomes, the specific Inattentive factor explained unique variation in 9 (primarily the academically oriented) outcomes and the specific Hyperactive-Impulsive factor explained unique variation in 2 outcomes. The general ADHD factor was more strongly correlated with each of the observed ADHD symptom scores (total, inattentive, hyperactive-impulsive) than was either specific factor. Results are discussed with respect to how changes in the conceptualization of the factor structure correspond to recent changes to the diagnostic criteria for ADHD, as well as whether/how individual differences in inattention and hyperactivity-impulsivity might be used to differentiate children who are diagnosed with ADHD.