Evidence for a Multi-Dimensional Latent Structural Model of Externalizing Disorders

Strong associations between conduct disorder (CD), antisocial personality disorder (ASPD) and substance use disorders (SUD) seem to reflect a general vulnerability to externalizing behaviors. Recent studies have characterized this vulnerability on a continuous scale, rather than as distinct categories, suggesting that the revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) take into account the underlying continuum of externalizing behaviors. However, most of this research has not included measures of disorders that appear in childhood [e.g., attention-deficit/hyperactivity disorder (ADHD) or oppositional defiant disorder (ODD)], nor has it considered the full range of possibilities for the latent structure of externalizing behaviors, particularly factor mixture models, which allow for a latent factor to have both continuous and categorical dimensions. Finally, the majority of prior studies have not tested multidimensional models. Using lifetime diagnoses of externalizing disorders from participants in the Fast Track Project (n?=?715), we analyzed a series of latent variable models ranging from fully continuous factor models to fully categorical mixture models. Continuous models provided the best fit to the observed data and also suggested that a two-factor model of externalizing behavior, defined as (1) ODD+ADHD+CD and (2) SUD with adult antisocial behavior sharing common variance with both factors, was necessary to explain the covariation in externalizing disorders. The two-factor model of externalizing behavior was then replicated using a nationally representative sample drawn from the National Comorbidity Survey-Replication data (n?=?5,692). These results have important implications for the conceptualization of externalizing disorders in DSM-5.     

Sources of covariation among attention-deficit/hyperactivity disorder, oppositional defiant disorder, and conduct disorder: the importance of shared environment.

Research has documented high levels of covariation among childhood externalizing disorders, but the etiology of this covariation is unclear. To unravel the sources of covariation among attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD), the authors studied 11-year-old twins (N = 1,506) from the Minnesota Twin Family Study. Symptom counts for each of these disorders were obtained from interviews administered to the twins and their mothers. A model was fit that allowed the parsing of genetic, shared environmental (factors that make family members similar to each other), and nonshared environmental (factors that make family members different from each other) contributions to covariation. The results revealed that although each disorder was influenced by genetic and environmental factors, a single shared environmental factor made the largest contribution to the covariation among ADHD, ODD, and CD.     

Externalizing Outcomes of Youth with and without ADHD: Time-Varying Prediction by Parental ADHD and Mediated Effects

Although parental attention-deficit/hyperactivity disorder (ADHD) is a risk factor for multiple negative youth outcomes, it is unknown how change in parental ADHD symptoms over time affects change in child ADHD symptoms; moreover, mediators of these predictions are largely unknown. Parents of 230 5–10 year-old children (68 % male) with (n = 120) and without ADHD (n = 110) were followed prospectively for 6–7 years across three separate waves. Parents self-reported their ADHD and depression symptoms and similarly rated offspring ADHD, oppositional defiant disorder (ODD), and conduct disorder (CD) symptoms; youth self-reported their substance use. Temporally-ordered mediators consisted of parental expressed emotion (EE), derived from the Five Minute Speech Sample, and self-reported positive and negative parenting behavior. Controlling for key demographics and parental depression symptoms, increasing parental ADHD symptoms were a time-varying predictor of worsening youth ADHD and ODD, although it was unrelated to change in CD and alcohol/substance use. Next, although EE facets (i.e., criticism, emotional over-involvement) did not mediate these predictions, negative parenting behavior significantly mediated predictions of youth ADHD (and marginally in predictions of ODD) from parental ADHD symptoms. These quasi-experimental findings suggest that parental ADHD symptoms are a potential unique causal risk factor for offspring ADHD and ODD; also, preventing negative parenting behavior secondary to parental ADHD symptoms is critical to improve trajectories of youth ADHD and ODD. We consider parental ADHD symptoms and family factors underlying emergent externalizing problems utilizing a developmental psychopathology framework, including implications for intervention and prevention.     

The role of a lifetime history of oppositional defiant and conduct disorders in adults with ADHD: implications for clinical practice

IntroductionAttention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD) are frequently co-occurring disorders in children and adolescents. However, their clinical status among adults is still under discussion. This study analyzes how the current clinical presentation of adult ADHD might be influenced by a lifetime history of CD and ODD. METHODS: We compared three groups of patients: ADHD without history of CD/ODD (n = 178), ADHD + history of ODD (n = 184), and ADHD + history of CD (n = 96). RESULTS: A history of CD (and to a lower extent ODD) is associated with a more severe and externalizing profile.ConclusionPast CD and ODD entail a significant negative mental health impact on persistent ADHD, reinforcing the importance of actively assessing the developmental history of adult ADHD patients.     

Evidence for the Trait-Impulsivity Etiological Model in a Clinical Sample: Bifactor Structure and Its Relation to Impairment and Environmental Risk

The trait-impulsivity etiological model assumes that a general factor (trait-impulsivity) underlies attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and other externalizing disorders. We investigated the plausibility of this assumption by testing the factor structure of ADHD and ODD in a bifactor framework for a clinical sample of 1420 children between 6 and 18 years of age (M = 9.99, SD = 3.34; 85% male). Further, the trait-impulsivity etiological model assumes that ODD emerges only if environmental risk factors are present. Our results support the validity of the trait-impulsivity etiological model, as they confirm that ADHD and ODD share a strong general factor of disruptive behavior (DB) in this clinical sample. Furthermore, unlike the subdimensions of ADHD, we found that the specific ODD factor explained as much true score variance as the general DB factor. This suggests that a common scale of ADHD and ODD may prove to be as important as a separate ODD subscale to assess externalizing problems in school-age children. However, all other subscales of ADHD may not explain sufficient true score variance once the impact of the general DB factor has been taken into consideration. In accordance with the trait-impulsivity model, we also showed that all factors, but predominantly the general factor and specific inattention factor, predicted parent-rated impairment, and that predominantly ODD and impulsivity are predicted by environmental risk factors.     

Unintentional Injury Risk in Children with Externalizing Behavior Disorders at Summer Camp

Children with externalizing behavior disorders such as attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD) have greatly increased risk of unintentional injury, but it is unclear what mechanisms are responsible for that increased risk. This study followed 22 children participating in a summer camp for children with ADHD. Injury incidents were recorded daily and a set of primary symptoms of behavioral disorders were recorded at 15-min intervals over the course of the 6-week summer camp experience (roughly 300 h of observing each child). We predicted symptoms of ODD and CD would be more strongly related to injury incidence than symptoms of ADHD. Results from univariate Poisson regression models confirmed our prediction. Symptoms of ODD and CD—violations and intentional aggression in particular—were related to injury incidence but symptoms of ADHD were not. This finding is consistent with a growing body of evidence that oppositional, noncompliant, and aggressive behavior patterns might be primarily responsible for increased risk for injury among children with externalizing behavior disorders. Thanks to Sylvie Mrug, Peter Winslett, and the other staff members of the STP camp for their cooperation.     

A confirmatory factor analysis on the DSM-IV ADHD and ODD symptoms: what is the best model for the organization of these symptoms?

Confirmatory factor analysis (CFA) was used to evaluate five different models for the organization of the DSM-IV ADHD and oppositional defiant disorder (ODD) symptoms (Model 1: a single factor model; Model 2: an ADHD and ODD two factor model; Model 3a: an inattention (INA), hyperactivity/impulsivity (HYP/IMP), and ODD three factor model; Model 3b: an INA, HYP/IMP, and ODD three factor model where the three IMP symptoms cross-load on the ODD factor; Model 4: an INA, HYP, IMP, and ODD four factor model). To evaluate these models, maternal ratings of ADHD and ODD symptoms were obtained at outpatient pediatric clinics on 742 children not in treatment and 91 children in treatment for ADHD. Model 3a resulted in a good fit as well as a significantly better fit than Model 2. Model 3a was also equivalent across treatment status, gender, and age groupings for the most part. Though Models 3b and 4 provided a statistically better fit than Model 3a, the improvement in fit was small and other model selection criteria argued against these more complex models.     

Measurement and structural invariance of parent ratings of ADHD and ODD symptoms across gender for American and Malaysian children

The purpose of this study was to examine the measurement (configural, metric, scalar, and residual) and structural (factor variance, factor covariance, and factor means) invariance of parent ratings of the attention-deficit/hyperactivity disorder - inattention (ADHD-IN), ADHD - hyperactivity/impulsivity (ADHD-HI), and oppositional defiant disorder (ODD) symptoms as described in the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) across boys and girls. In an American pediatric sample (N = 1,015) and a Malaysian elementary school-age sample (N = 928), there was strong support for configural, metric, scalar, residual, factor variance, and covariance invariance across gender within each sample. Both American and Malaysian boys had significantly higher scores on the ADHD-IN and ADHD-HI factor means than did girls, whereas only in the American sample did boys score significantly higher on the ODD factor than did girls. The implications of the results for the study of gender, ethnic, and cultural differences associated with ADHD and ODD are discussed.     

Do Genetic Factors Explain the Links Between Callous-Unemotional,Attention Hyperactivity and Oppositional Defiant Problems in Toddlers?

Research demonstrates that callous-unemotional (CU) behaviors, Attention Deficit Hyperactivity Disorder (ADHD) and Oppositional Defiant Problems (ODD) are related, but little is known about the sources of covariation among the three externalizing behaviors. The present study looked at genetic and environmental links between all three behavioral domains in twins at ages 2 and 3 years (MZ = 145, DZ = 169), a time when CU behaviors are beginning to emerge. CU, ADHD, and ODD behaviors as assessed using the Child Behavior Checklist 1.5–5 (Achenbach and Rescorla 2000) were strongly interrelated at both ages. Genetic factors primarily explained the covariation among the three behavioral domains via a common externalizing factor; however, there were also genetic factors unique to each behavior. Furthermore, the majority of nonshared environmental influences on each externalizing behavior were behavior-specific. The heritable externalizing factor was highly stable across age, largely due to genetic factors shared across ages 2 and 3 years. Despite their extensive phenotypic and genetic overlap, CU, ADHD, and ODD behaviors have unique genetic and nonshared environmental influences as early as toddlerhood. This supports phenotypic research showing that the three are related but distinct constructs in very young children.     

Internal Validity of the Disruptive Behavior Disorder Symptoms: Implications from Parent Ratings for a Dimensional Approach to Symptom Validity

A dimensional approach was used to evaluate the internal validity of the DSM-III-R ADHD-inattention, ADHD-hyperactivity/impulsivity, oppositional defiant disorder (ODD), and conduct disorder (CD) symptoms (i.e., whether a symptom has a stronger correlation with its own dimension than the other three). Parents rated 4,019 children between the ages of 2 and 19 on these symptoms. The results showed that 5 of the 6 inattention symptoms, 3 of the 4 hyperactivity symptoms, 1 of the 4 impulsivity symptoms, 6 of the 9 oppositional defiant disorder symptoms, and 8 of the 11 CD symptoms had significant internal validity. Confirmatory factor analysis (CFA) found support for inattention, hyperactivity/impulsivity, oppositional defiant, and conduct disorder dimensions. Multiple-group CFA also found support for factor pattern and loading invariance across gender. The implications of these results as well as the merits of the dimensional approach to symptom validity are discussed in the context of the DSM-IV changes in ADHD, ODD, and CD.     

ODD dimensions, ADHD, and callous-unemotional traits as predictors of treatment response in children with disruptive behavior disorders

To answer several questions pertinent to DSM-V, the authors examined the predictive validity of pretreatment oppositional defiant disorder (ODD) dimensions, attention-deficit/hyperactivity disorder (ADHD), and callous-unemotional (CU) traits in relation to several treatment outcomes in 177 children diagnosed with ODD or conduct disorder (CD). Multiple informants completed diagnostic interviews and rating scales at 6 assessment points (pretreatment to 3-year follow-up) to document emotional and behavioral outcomes. After controlling for pretreatment CD, the ODD dimension of hurtfulness was related to treatment-resistant CD, delinquent behaviors, and externalizing problems. In contrast, the ODD dimension tapping irritability was associated with treatment-resistant ODD, internalizing problems, and global functional impairment following treatment. Whereas pretreatment ADHD was associated with posttreatment ODD and social problems, it was unrelated to posttreatment CD symptoms and diagnosis. Contrary to predictions, CU traits were unrelated to any posttreatment outcomes after controlling for other covariates. These findings remained after controlling for measures of pretreatment global functional impairment.     

The Factor Structure of Anxiety and Depressive Disorders in a Sample of Clinic-Referred Adolescents

The current study used confirmatory factor analysis (CFA) to examine the factor structure of anxiety and depressive disorders in a sample of clinic-referred adolescents, aged between 12 and 18 years, for diagnoses based on parent (N?=?655; male?=?441) and adolescent (N?=?626; male?=?417) interviews. Three models were examined: a 1-factor model, with all anxiety and depressive disorders in a single factor; a DSM-based 2-factor model, with anxiety disorders in one factor, and depressive disorders in another factor; and an alternate 2-factor model, with fear related anxiety disorders in one factor, and other anxiety and depressive disorders in another factor. The findings indicated support for all three models. Also, ADHD and ODD/CD were associated with only the shared variances between the latent factors in the 2-factor models, and not their unique variance. The implications of the findings for taxonomy, comorbidity, and clinical practice are discussed.     

Waxing and waning in concert: dynamic comorbidity of conduct disorder with other disruptive and emotional problems over 7 years among clinic-referred boys

Six waves of structured diagnostic assessments were conducted of 168 clinic-referred 7- to 12-year-olds, over 7 years. Wave-to-wave changes in the number of conduct disorder (CD) behaviors were paralleled by correlated changes in the numbers of symptoms of oppositional defiant disorder (ODD), attention-deficit/hyperactivity disorder (ADHD), depression, and anxiety. In addition, CD in Wave 1 predicted levels of ODD, ADHD, depression, and anxiety in later waves when initial levels of those symptoms were controlled, but only ODD in Wave 1 predicted CD in later waves when initial CD levels were controlled. These findings indicate a striking degree of dynamic comorbidity between CD and other types of psychopathology and provide an initial empirical framework for needed developmental models of comorbidity.     

The structure of childhood disruptive behaviors

Attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) frequently co-occur. Comorbidity of these 2 childhood disruptive behavior domains has not been satisfactorily explained at either a structural or etiological level. The current study evaluated a bifactor model, which allows for a "g" factor in addition to distinct component factors, in relation to other models to improve understanding of the structural relationship between ADHD and ODD. Participants were 548 children (321 boys, 227 girls) between the ages of 6 years and 18 years who participated in a comprehensive diagnostic assessment incorporating parent and teacher ratings of symptoms. Of these 548 children, 153 children were diagnosed with ADHD (without ODD), 114 children were diagnosed with ADHD + ODD, 26 children were diagnosed with ODD (without ADHD), and 239 children were classified as non-ADHD/ODD comparison children (including subthreshold cases). ADHD symptoms were assessed via parent report on a diagnostic interview and via parent and teacher report on the ADHD Rating Scale. ODD symptoms were assessed via teacher report. A bifactor model of disruptive behavior, comprising a "g" factor and the specific factors of ADHD and ODD, exhibited best fit, compared to 1-factor, 2-factor, 3-factor, and 2nd-order factor models of disruptive behaviors. It is concluded that a bifactor model of childhood disruptive behaviors is superior to existing models and may help explain common patterns of comorbidity between ADHD and ODD.     

Understanding the Covariation Among Childhood Externalizing Symptoms: Genetic and Environmental Influences on Conduct Disorder,Attention Deficit Hyperactivity Disorder,and Oppositional Defiant Disorder Symptoms

Conduct disorder (CD), attention deficit hyperactivity disorder (ADHD), and oppositional defiant disorder (ODD) are common childhood externalizing disorders that frequently co-occur. However, the causes of their comorbidity are not well understood. To address that question, we analyzed data from > 600 Finnish twin pairs, who completed standardized interviews at age 14. Behavior genetic methods were used to examine how genetic/environmental factors contribute to each disorders symptoms and to their covariation. We found significant genetic effects on each disorder with only modest evidence of shared environmental influences. Our data suggest the comorbidity among CD, ADHD, and ODD is primarily explained by shared genetic influences; however, each disorder was also under unique genetic influence, supporting the distinction of each disorder.     

A Systematic Review and Meta-analysis of Neuroimaging in Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD) Taking Attention-Deficit Hyperactivity Disorder (ADHD) Into Account

Oppositional defiant disorder (ODD) and conduct disorder (CD) are common behavioural disorders in childhood and adolescence and are associated with brain abnormalities. This systematic review and meta-analysis investigates structural (sMRI) and functional MRI (fMRI) findings in individuals with ODD/CD with and without attention-deficit hyperactivity disorder (ADHD). Online databases were searched for controlled studies, resulting in 12 sMRI and 17 fMRI studies. In line with current models on ODD/CD, studies were classified in hot and cool executive functioning (EF). Both the meta-analytic and narrative reviews showed evidence of smaller brain structures and lower brain activity in individuals with ODD/CD in mainly hot EF-related areas: bilateral amygdala, bilateral insula, right striatum, left medial/superior frontal gyrus, and left precuneus. Evidence was present in both structural and functional studies, and irrespective of the presence of ADHD comorbidity. There is strong evidence that abnormalities in the amygdala are specific for ODD/CD as compared to ADHD, and correlational studies further support the association between abnormalities in the amygdala and ODD/CD symptoms. Besides the left precuneus, there was no evidence for abnormalities in typical cool EF related structures, such as the cerebellum and dorsolateral prefrontal cortex. Resulting areas are associated with emotion-processing, error-monitoring, problem-solving and self-control; areas associated with neurocognitive and behavioural deficits implicated in ODD/CD. Our findings confirm the involvement of hot, and to a smaller extent cool, EF associated brain areas in ODD/CD, and support an integrated model for ODD/CD (e.g. Blair, Development and Psychopathology, 17(3), 865-891, 2005).     

Irritability and Emotional Impulsivity as Core Feature of ADHD and ODD in Children

The categorical approach of diagnosing mental disorders entails the problem of frequently occurring comorbidities, suggesting a more parsimonious structure of psychopathology. In this study, we therefore aim to assess how affective dysregulation (AD) is associated with attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) in children. To assess AD in children aged 8–12 years (n?=?391), we employed the parent version of a newly constructed parent rating scale. Following item reduction, we conducted exploratory and confirmatory factor analyses to establish a factorial structure of AD. One core dimension was identified, comprising irritability and emotional impulsivity, and two smaller dimensions, comprising positive emotionality and exuberance. Subsequently, we examined five different latent factor models – a unidimensional model, a first-order correlated factor model, a second-order correlated factor model, a traditional bifactor model, and a bifactor S-1 model, in which the first-order factor AD-Irritability/Emotional Impulsivity (II) was modeled as the general reference factor. A bifactor S-1 model with the a priori defined general reference domain AD-II provided the best fit to our data and was straightforward to interpret. This model showed excellent model fit and no anomalous factor loadings. This still held true, when comparing it to bifactor S-1 models with ADHD/ODD-related reference factors. Differential correlations with emotion regulation skills and the established Parent Proxy Anger Scale validate the interpretation of the different dimensions. Our results suggest that irritability/emotional impulsivity might be a common core feature of ADHD and ODD.

     

Negative Halo Effects in Parent Ratings of ADHD,ODD, and CD

Attention-deficit/hyperactivity disorder (ADHD), Oppositional Defiant Disorder (ODD), and Conduct Disorder (CD) are highly comorbid, with symptoms that share some similarities. The evidence-based diagnostic process for these disorders includes ratings from adults in the child’s life to assess behavior across settings, so it is important to understand how these raters think about potentially overlapping symptoms. Researchers have identified negative halo effects in ratings of ADHD and ODD symptoms, but ratings of CD have not been examined in these prior studies. Thus, the current study extended past research to examine negative halo effects in parent ratings of the predominantly hyperactive-impulsive presentation of ADHD (i.e., ADHD/HI), ODD, and CD. Parent participants read one of four vignettes that portrayed an 11-year-old boy displaying symptoms of ADHD/HI, ODD, CD, or typical development, and then completed a disruptive behavior scale. The general trend we found was that the presence of a relatively more severe disorder (i.e., CD) artificially inflated ratings of - or showed a negative halo effect for - the relatively less severe disorder (i.e., ADHD/HI), but with some nuance as discussed in the paper. These findings explain and validate how important it is that clinicians conduct evidence-based psychological assessments to decrease the chance of misdiagnosis.

     

Do Executive Function Deficits Differentiate Between Adolescents with ADHD and Oppositional Defiant/Conduct Disorder? A Neuropsychological Study Using the Six Elements Test and Hayling Sentence Completion Test

Two neuropsychological measures of executive functions—Six Elements Tests (SET) and Hayling Sentence Completion Test (HSCT)—were administered to 110 adolescents, aged 12–15 years. Participants comprised four groups: Attention Deficit Hyperactivity Disorder (ADHD) only (n = 35), ADHD and Oppositional Defiant Disorder/Conduct Disorder (ODD/CD) (n = 38), ODD/CD only (n = 11), and a normal community control group (n = 26). Results indicated that adolescents with ADHD performed significantly worse on both the SET and HSCT than those without ADHD, whether or not they also had ODD/CD. The adolescents with ADHD and with comorbid ADHD and ODD/CD were significantly more impaired in their ability to generate strategies and to monitor their ongoing behavior compared with age-matched controls and adolescents with ODD/CD only. It is argued that among adolescents with clinically significant levels of externalizing behavior problems, executive function deficits are specific to those with ADHD. The findings support the sensitivity of these two relatively new tests of executive functions and their ecological validity in tapping into everyday situations, which are potentially problematic for individuals with ADHD.