The Affective Side of Disruptive Behavior: Toward Better Understanding, Assessment, and Treatment.

Historically, much of the progress made in youth mental health research can be classified as focusing on externalizing problems, characterized by disruptive behavior (e.g. aggression, defiance), or internalizing problems, characterized by intense negative affect (e.g. depression, anxiety). Until recently, however, less attention has been given to topics that lie somewhere in between these domains, topics that we collectively refer to as the affective side of disruptive behavior. Like the far side of the moon, the affective side of disruptive behavior captures facets of the phenomenon that may be less obvious or commonly overlooked, but are nonetheless critical to understand. This affective side clarifies socially disruptive aspects of traditionally "externalizing" behavior by elucidating proximal causation via intense negative affect (traditionally "internalizing"). Such problems include irritability, frustration, anger, temper loss, emotional outbursts, and reactive aggression. Given a recent explosion of research in these areas, efforts toward integration are now needed. This special issue was developed to help address this need. Beyond the present introductory article, this collection includes 4 empirical articles on developmental psychopathology topics, 4 empirical articles on applied treatment/assessment topics, 1 evidence base update review article on measurement, and 2 future directions review articles concerning outbursts, mood, dispositions, and youth psychopathology more broadly. By deliberatively investigating the affective side of disruptive behavior, we hope these articles will help bring about better understanding, assessment, and treatment of these challenging problems, for the benefit of youth and families.

Irritability across adolescence: Examining longitudinal trajectory, stability, and associations with psychopathology and functioning at age 18.

BACKGROUND: Irritability, marked by diminished frustration tolerance, holds significant implications for youth mental health treatment. Despite prior research on irritability trajectories, understanding of individual differences during adolescence remains limited. This study examines the stability and trajectory of irritability across ages 12-18, investigating associations with psychopathology and functioning at age 18. METHODS: A community sample of families with 3-year-old children (N = 518) was recruited via commercial mailing lists. Irritability was assessed at ages 12, 15, and 18 using the Affective Reactivity Index. Psychopathology at age 18 was evaluated with the Kiddie Schedule for Affective Disorders and Schizophrenia, and functioning was assessed through the UCLA Life Stress Interview. Measurement invariance analyses and latent growth curve modeling were conducted within a structural equation modeling (SEM) framework. RESULTS: Configural, metric, and scalar invariance models were supported. Elevated irritability at age 12 predicted adverse outcomes at age 18, including increased psychotropic medication use, mental health treatment, suicidal ideation, self-injury, and psychiatric disorders. Importantly, these associations persisted even after accounting for corresponding variables at age 12. The trajectory of irritability during early adolescence significantly predicted heightened risks for various outcomes at age 18, including suicidal ideation, depression, anxiety, disruptive behavior disorders, and impaired interpersonal functioning. DISCUSSION: Limitations include using only youth-reported data at age 18, limited generalizability from a mostly White, middle-class sample, and insufficient exploration of the broader developmental trajectory of irritability. Nevertheless, the findings emphasize the crucial role of irritability's trajectory in influencing various psychopathological and functional outcomes in late adolescence.

What I see, what you say: How cross-method variation sharpens characterization of irritability in early childhood.

OBJECTIVES: Identification of clinically significant irritability in preschool age is important to implement effective interventions. However, varying informant and measurement methods display distinct patterns. These patterns are associated with concurrent and future mental health concerns. Patterns across multi-informant methods in early-childhood irritability may have clinical utility, identifying risk for impaired psychosocial functioning. METHODS: Using data from the Multidimensional Assessment of Preschoolers Study (N = 425), latent profile analysis identified irritability patterns through the parent-reported Multidimensional Assessment Profile Scales-Temper Loss (MAPS-TL), parent-reported interviewer-rated Preschool Age Psychiatric Assessment (PAPA), and observer-rated Disruptive Behavior Diagnostic Observation Schedule (DB-DOS). These profiles were characterized on protective factors, global functioning, and mental health syndromes, concurrently and at early school age and preadolescent follow-up. RESULTS: Fit indices favored a five-class model: Low All, High Observation with Examiner (high DB-DOS Examiner Context), High All, High Parent Report (high MAPS-TL/PAPA), and Very High Parent Report (very high MAPS-TL/PAPA). Whereas Low All and High Observation with Examiner exhibited strong psychosocial functioning, remaining profiles showed impaired psychosocial functioning, with the Very High Parent Report group showing higher impairment at follow-ups, ds = 0.37-1.25. CONCLUSIONS: Multi-informant measurements of irritability may have utility for clinical prediction, and future studies should test utility for diagnostic precision.

Neural Responses to Intranasal Oxytocin in Youths With Severe Irritability.

OBJECTIVE: The authors investigated the neural impact of intranasal oxytocin on emotion processing areas in youths with severe irritability in the context of disruptive mood and behavior disorders. METHODS: Fifty-two participants with severe irritability, as measured by a score ≥4 on the Affective Reactivity Index (ARI), with diagnoses of disruptive behavior disorders (DBDs) and/or disruptive mood dysregulation disorder (DMDD) were randomly assigned to treatment with intranasal oxytocin or placebo daily for 3 weeks. Assessments were conducted at baseline and at the end of the trial; the primary outcomes were measures of irritability on the ARI and ratings on the Clinical Global Impressions severity scale (CGI-S) focusing on DBD and DMDD symptoms, and secondary outcomes included the CGI improvement scale (CGI-I) and ratings of proactive and reactive aggressive behavior on the Reactive-Proactive Aggression Questionnaire. Forty-three participants (22 in the oxytocin group and 21 in the placebo group) completed pre- and posttreatment functional MRI (fMRI) scans with the affective Stroop task. RESULTS: Youths who received oxytocin showed significant improvement in CGI-S and CGI-I ratings compared with those who received placebo. In the fMRI data, blood-oxygen-level-dependent (BOLD) responses to emotional stimuli in the dorsomedial prefrontal cortex and posterior cingulate cortex were significantly reduced after oxytocin compared with placebo. These BOLD response changes were correlated with improvement in clinical severity. CONCLUSIONS: This study provides initial and preliminary evidence that intranasal oxytocin may induce neural-level changes in emotion processing in youths with irritability in the context of DBDs and DMDD. This may lead to symptom and severity changes in irritability.

Irritability in Youths: A Critical Integrative Review.

Irritability, defined as proneness to anger that may impair an individual's functioning, is common in youths. There has been a recent upsurge in relevant research. The authors combine systematic and narrative review approaches to integrate the latest clinical and translational findings and provide suggestions for addressing research gaps. Clinicians and researchers should assess irritability routinely, and specific assessment tools are now available. Informant effects are prominent, are stable, and vary by age and gender. The prevalence of irritability is particularly high among individuals with attention deficit hyperactivity disorder, autism spectrum disorder, and mood and anxiety disorders. Irritability is associated with impairment and suicidality risk independent of co-occurring diagnoses. Developmental trajectories of irritability (which may begin early in life) have been identified and are differentially associated with clinical outcomes. Youth irritability is associated with increased risk of anxiety, depression, behavioral problems, and suicidality later in life. Irritability is moderately heritable, and genetic associations differ based on age and comorbid illnesses. Parent management training is effective for treating psychological problems related to irritability, but its efficacy in treating irritability should be tested rigorously, as should novel mechanism-informed interventions (e.g., those targeting exposure to frustration). Associations between irritability and suicidality and the impact of cultural context are important, underresearched topics. Analyses of large, diverse longitudinal samples that extend into adulthood are needed. Data from both animal and human research indicate that aberrant responses to frustration and threat are central to the pathophysiology of irritability, revealing important translational opportunities.

An expert opinion on the pharmacological interventions for Disruptive Mood Dysregulation Disorder (DMDD).

INTRODUCTION: Disruptive Mood Dysregulation Disorder (DMDD) was officially introduced as a new diagnostic entity in the Diagnostic and Statistical Manual of Mental Disorder, Fifth Edition (DSM-5), under the category of depressive disorders. AREAS COVERED: A comprehensive overview and a critical commentary on the currently investigated psychopharmacological approaches for the treatment of DMDD have been here provided. EXPERT OPINION: Behavioral and psychosocial interventions should be considered as first-line treatment strategies. When ineffective or partially effective, psychopharmacological strategy is recommended. Overall, pharmacological strategy should be preferred in those individuals with psychiatric comorbidities (e.g. ADHD). Indeed, so far published studies on pharmacological strategies in DMDD are scant and heterogeneous (i.e. age, assessment tools, symptomatology profile, comorbidity, and so forth). Therefore, DMDD psychopharmacological guidelines are needed, particularly to guide clinicians toward the patient's typical symptom profile who could benefit from psychopharmacological strategy.

Long-term cortisol secretion in attention deficit hyperactivity disorder: roles of sex, comorbidity, and symptom presentation.

Low activity of the hypothalamic-pituitary-adrenal axis (HPAA) has been found in children with attention deficit hyperactivity disorder (ADHD). The condition may be related to the reduced attention regulation capacity and/or to comorbid oppositional defiant or conduct disorder (ODD/CD). Sex differences are probable but not sufficiently studied. We analyzed the HPAA activity and sympathetic nervous system reactivity (SR) in children with ADHD while accounting for ADHD symptom presentation, comorbidity, and sex differences. The sample comprised 205 children, 98 (61 boys, 37 girls) with ADHD and 107 (48 boys, 59 girls) healthy controls. DSM-5 phenotypic symptom presentation and comorbid ODD/CD were assessed using clinical interviews. Hair cortisol concentration (HCC) was used to assess the long-term, cumulative activity of the HPAA. SR was assessed via skin conductance response (SCR). For control purposes, comorbid internalizing symptoms and indicators of adverse childhood experiences (ACE) were assessed. Children were medication naive. Boys presenting with predominantly inattentive symptoms (ADHD-I) showed lower HCC than healthy boys. Girls presenting with combined symptoms (ADHD-C) showed higher HCC than did healthy girls (p's < 0.05, sex-by-group interaction, F (2,194) = 4.09, p = 0.018). Boys with ADHD plus ODD/CD showed a blunted SR (p < 0.001, sex-by-group interaction, F (2,172) = 3.08, p = 0.048). Adjustment for ACE indicators led to non-significant differences in HCC but did not affect differences in SR. HCC constitutes an easily assessable, reliable, and valid marker of phenotypic ADHD-related features (i.e. symptom presentation and comorbidity). It indicates more homogenous subgroups of ADHD and might point to specifically involved pathophysiological processes.

Development of symptoms of oppositional defiant disorder from preschool to adolescence: the role of bullying victimization and emotion regulation.

BACKGROUND: Childhood oppositional defiant disorder (ODD) is associated with adverse outcomes which can continue to impair life well into adulthood. Identifying modifiable etiological factors of ODD is therefore essential. Although bullying victimization and poor emotion regulation are assumed to be risk factors for the development of ODD symptoms, little research has been conducted to test this possibility. METHODS: A sample (n = 1,042) from two birth cohorts of children in the city of Trondheim, Norway, was assessed biennially from age 4 to 14 years. Parents and children (from age 8) were assessed with clinical interviews to determine symptoms of ODD, children reported on their victimization from bullying, and teachers reported on children's emotion regulation. RESULTS: Oppositional defiant disorder symptoms increased from age 4 to 6, from age 8 to 10, and then started to wane as children entered adolescence. A Random Intercept Cross-Lagged Panel Model revealed that increased emotion regulation predicted a reduced number of ODD symptoms across development (ß = -.15 to -.13, p < .001). This prediction was equally strong for the angry/irritable and argumentative/defiant dimensions of ODD. No longitudinal links were observed between bullying victimization and ODD symptoms. CONCLUSIONS: Improving emotion regulation skills may protect against ODD symptoms throughout childhood and adolescence.

Emotion regulation as central to psychopathology across childhood and adolescence: a commentary on Nobakht et al. (2023).

An important goal of clinical/developmental research is to identify factors contributing to the onset and maintenance of psychopathology - particularly factors that could be modified through intervention. Large-scale, multi-informant, longitudinal studies provide valuable opportunities for testing such etiological hypotheses, as illustrated by Nobakht et al.'s recent six-wave cohort study spanning ages 4-14. At a within-person level, emotion regulation (ER) deficits consistently predicted oppositional defiant disorder (ODD) symptoms (including both irritability and defiance), whereas victimization did not. These results comport with growing evidence highlighting ER's centrality to ODD and psychopathology more broadly. While the ER findings carry promising implications, caution is warranted in interpreting the results for victimization given that its association with psychopathology is well-documented. More research is needed to test precise questions about within- and between-person processes involving ER, victimization, and psychopathology across development. Pressing research questions include whether, how, and when youths' ER can be modified, and with what effects on clinical outcomes.

Executive function in children with disruptive mood dysregulation disorder compared to attention-deficit/hyperactivity disorder and oppositional defiant disorder, and in children with different irritability levels.

Addressing current challenges in research on disruptive mood dysregulation disorder (DMDD), this study aims to compare executive function in children with DMDD, children with attention-deficit/hyperactivity disorder (ADHD), and children with oppositional defiant disorder (ODD). We also explore associations between irritability, a key DMDD characteristic, and executive function in a clinical sample regardless of diagnosis. Our sample include children (6-12 years) referred to child psychiatric clinics. Measures of daily-life (parent-reported questionnaire) and performance-based (neuropsychological tasks) executive function were applied. Identifying diagnoses, clinicians administered a standardized semi-structured diagnostic interview with parents. Irritability was assessed by parent-report. First, we compared executive function in DMDD (without ADHD/ODD), ADHD (without DMDD/ODD), ODD (without DMDD/ADHD) and DMDD + ADHD (without ODD). Second, we analyzed associations between executive function and irritability using the total sample. In daily life, children with DMDD showed clinically elevated and significantly worse emotion control scores compared to children with ADHD, and clinically elevated scores on cognitive flexibility compared to norm scores. Children with DMDD had significantly less working memory problems than those with ADHD. No differences were found between DMDD and ODD. Increased irritability was positively associated with emotional dyscontrol and cognitive inflexibility. For performance-based executive function, no diagnostic differences or associations with irritability were observed. We discuss how, in daily life, children with high irritability-levels get overwhelmed by feelings without accompanying regulatory capacities.

START NOW: a cognitive behavioral skills training for adolescent girls with conduct or oppositional defiant disorder - a randomized clinical trial.

BACKGROUND: Conduct disorder (CD) and oppositional defiant disorder (ODD) both convey a high risk for maladjustment later in life and are understudied in girls. Here, we aimed at confirming the efficacy of START NOW, a cognitive-behavioral, dialectical behavior therapy-oriented skills training program aiming to enhance emotion regulation skills, interpersonal and psychosocial adjustment, adapted for female adolescents with CD or ODD. METHODS: A total of 127 girls were included in this prospective, cluster randomized, multi-center, parallel group, quasi-randomized, controlled phase III trial, which tested the efficacy of START NOW (n = 72) compared with standard care (treatment as usual, TAU, n = 55). All female adolescents had a clinical diagnosis of CD or ODD, were 15.6 (±1.5) years on average (range: 12-20 years), and were institutionalized in youth welfare institutions. The two primary endpoints were the change in number of CD/ODD symptoms between (1) baseline (T1) and post-treatment (T3), and (2) between T1 and 12-week follow-up (T4). RESULTS: Both treatment groups showed reduced CD/ODD symptoms at T3 compared with T1 (95% CI: START NOW = -4.87, -2.49; TAU = -4.94, -2.30). There was no significant mean difference in CD/ODD symptom reduction from T1 to T3 between START NOW and TAU (-0.056; 95% CI = -1.860, 1.749; Hedge's g = -0.011). However, the START NOW group showed greater mean symptom reduction from T1 to T4 (-2.326; 95% CI = -4.274, -0.378; Hedge's g = -0.563). Additionally, secondary endpoint results revealed a reduction in staff reported aggression and parent-reported irritability at post assessment. CONCLUSIONS: Although START NOW did not result in greater symptom reduction from baseline to post-treatment compared with TAU, the START NOW group showed greater symptom reduction from baseline to follow-up with a medium effect size, which indicates a clinically meaningful delayed treatment effect.

Impulsivity as key bridge symptoms in cross-sectional and longitudinal networks of ADHD and ODD.

BACKGROUND: Impulsivity is viewed as key to attention-deficit/hyperactivity disorder (ADHD) and disruptive behavior disorders (DBD). Yet, to date, no work has provided an item-level analysis in longitudinal samples across the critical developmental period from childhood into adolescence, despite prior work suggesting items exhibit differential relevance with respect to various types of impairment. The current study conducted a novel longitudinal network analysis of ADHD and oppositional defiant disorder (ODD) symptoms between childhood and adolescence, with the important applied prediction of social skills in adolescence. METHODS: Participants were 310 children over-recruited for clinical ADHD issues followed longitudinally for six years in total with gold standard diagnostic procedures and parent and teacher ratings of symptoms and social outcomes. RESULTS: Findings from baseline, Year 3, and Year 6 suggested Difficulty waiting turn, Blurts, and Interrupts/intrudes were key bridge items across cross-sectional and longitudinal parent-reported DBD networks. Furthermore, shortened symptom lists incorporating these symptoms were stronger predictors of teacher-rated social skills 5 years later compared to total DBD scores. CONCLUSIONS: Such findings are consistent with the trait impulsivity theory of DBD and ADHD and may inform useful screening tools and personalized intervention targets for children at risk for DBD during adolescence.

Novel Oppositional Defiant Disorder or Conduct Disorder 24 Months After Traumatic Brain Injury in Children and Adolescents.

OBJECTIVE: The authors sought to identify predictive factors of new-onset or novel oppositional defiant disorder or conduct disorder assessed 24 months after traumatic brain injury (TBI). METHODS: Children ages 5 to 14 years who had experienced TBI were recruited from consecutive hospital admissions. Soon after injury, participants were assessed for preinjury characteristics, including psychiatric disorders, socioeconomic status (SES), psychosocial adversity, and family function, and the presence and location of lesions were documented by MRI. Psychiatric outcomes, including novel oppositional defiant disorder or conduct disorder, were assessed 24 months after injury. RESULTS: Of the children without preinjury oppositional defiant disorder, conduct disorder, or disruptive behavior disorder not otherwise specified who were recruited in this study, 165 were included in this sample; 95 of these children returned for the 24-month assessment. Multiple imputation was used to address attrition. The prevalence of novel oppositional defiant disorder or conduct disorder was 23.7 out of 165 (14%). In univariable analyses, novel oppositional defiant disorder or conduct disorder was significantly associated with psychosocial adversity (p=0.049) and frontal white matter lesions (p=0.016) and was marginally but not significantly associated with SES. In the final multipredictor model, frontal white matter lesions were significantly associated with novel oppositional defiant disorder or conduct disorder (p=0.021), and psychosocial adversity score was marginally but not significantly associated with the outcome. The odds ratio of novel oppositional defiant disorder or conduct disorder among the children with versus those without novel depressive disorder was significantly higher for girls than boys (p=0.025), and the odds ratio of novel oppositional defiant disorder or conduct disorder among the children with versus those without novel attention-deficit hyperactivity disorder (ADHD) was significantly higher for boys than girls (p=0.006). CONCLUSION: Approximately 14% of children with TBI developed oppositional defiant disorder or conduct disorder. The risk for novel oppositional defiant disorder or conduct disorder can be understood from a biopsychosocial perspective. Sex differences were evident for comorbid novel depressive disorder and comorbid novel ADHD.

Differential Effects of Disruptive Mood Dysregulation Disorder Comorbidity in Attention Deficit Hyperactivity Disorder on Social Cognition and Empathy.

OBJECTIVE: This study aimed to investigate social cognition and empathy properties in children among Disruptive Mood Dysregulation Disorder (DMDD) + Attention and Hyperactivity Disorder(ADHD); ADHD and healthy controls from Türkiye. METHODS: Twenty-two children with DMDD were compared to matched 30 children with ADHD and 60 healthy controls. We administered Affective Reactivity Index (ARI), KaSi Empathy Scale, Kiddie-SADS, and Reading Mind in the Eyes Test (RMET) to evaluate Theory of Mind skills to all study participants. RESULTS: DMDD + ADHD group had lower performance in ToM skills and empathy than in two groups. The ARI scores were found to be statistically significantly higher in the DMDD group than in two groups. It was also found that ARI, empathy, and ToM scores were significantly related in children with DMDD + ADHD. CONCLUSION: These results might be important to understand the difficulties in social functioning and interpersonal relationship in children with DMDD and ADHD. Children with DMDD may attend specific therapeutic programs which include specific techniques in social cognition, emotion regulation, and irritability.

Evidence-Based Assessment of DSM-5 Disruptive, Impulse Control, and Conduct Disorders.

The assessment of oppositional defiant disorder, conduct disorder, antisocial personality disorder, and intermittent explosive disorder-the Disruptive, Impulse Control and Conduct Disorders-can be affected by biases in clinical judgment, including overestimating concerns about distinguishing symptoms from normative behavior and stigma associated with diagnosing antisocial behavior. Recent nosological changes call for special attention during assessment to symptom dimensions of limited prosocial emotions and chronic irritability. The present review summarizes best practices for evidence-based assessment of these disorders and discusses tools to identify their symptoms. Despite the focus on disruptive behavior disorders, their high degree of overlap with disruptive mood dysregulation disorder can complicate assessment. Thus, the latter disorder is also included for discussion here. Good practice in the assessment of disruptive behavior disorders involves using several means of information gathering (e.g., clinical interview, standardized rating scales or checklists), ideally via multiple informants (e.g., parent-, teacher-, and self-report). A commitment to providing a full and accurate diagnostic assessment, with careful and attentive reference to diagnostic guidelines, will mitigate concerns regarding biases.

Dysfunction of visual novelty detection in physical but not social anhedonia in a non-clinical sample

Background/objective: Despite its obvious motivational impairment, anhedonia as a transdiagnostic psychopathological construct is accompanied by deficits in attention function. Previous studies have identified voluntary attention anomalies in anhedonia, but its involuntary attention has received less study. Method: Using a visual novelty oddball task, the current event-related potential study assessed electrophysical correlates underlying mismatch detection in anhedonia with a non-clinical sample. Well-matched healthy control (N = 28; CNT), social anhedonia (N = 27; SA), and physical anhedonia (N = 26; PA) groups were presented standard, target, and perceptually novel stimuli while their EEG was recording. Results: The PA group relative to the CNT group exhibited a reduced N2 to novel stimuli but not to target stimuli. In contrast, the SA group as compared to the other two groups showed comparable N2 responses to both target and novel stimuli. Control analyses indicated that these patterns were unaffected by depression symptoms. Conclusions: These findings suggest that anhedonia is a heterogenous construct associated with impairments in early detection of visual novelty in physical but not social anhedonia, highlighting that dysfunction in involuntary attention may play a mediating role in the development, maintenance, and consequences of anhedonia-related psychopathology. (AU)

Characteristic Similarities of Irritability Between Autism and Disruptive Mood Dysregulation Disorder.

Objective: Irritability in children with autism spectrum disorder (ASD) is prominent and often leads to distress to both autistic children and their families. However, the nature of irritability in autism and the difference from nonautistic children have rarely been examined. This study aimed to investigate the clinical characteristics of irritability in autism, and to compare the symptom profiles with those of disruptive mood dysregulation disorder (DMDD) in nonautistic children. Methods: Fifty-six children aged 7-17 years (mean age 10.36 ± 3.05) were recruited into this study (21 with DMDD, 21 with high-functioning autism [hfASD], and 14 healthy volunteers [HV]). Their parents completed the Aberrant Behavior Checklist-Irritability (ABC-I) subscale and the Strengths and Difficulties Questionnaire (SDQ) parent report form. The ABC-I subscale was analyzed as a whole and broken into subsets (ABC-I-Irritability, ABC-I-Agitation, and ABC-I-Crying). The symptom profiles of irritability and the association with psychosocial difficulties were compared between groups. Results: The ABC-I-Irritability scores of children with hfASD closely matched to those of children with DMDD. In addition, both DMDD and hfASD groups could be differentiated from HV group in five of the six items except "depressed mood." However, in the ABC-I-Agitation scale, children with DMDD, but not hfASD, had higher scores in "Aggressive to other patients and staff" and "Stamps feet while banging objects or slamming doors" than HV. Regarding psychosocial outcomes, irritability in children with DMDD and hfASD were associated with emotional problems as measured by the SDQ. Moreover, irritability in DMDD was associated with conduct problems, and the hfASD group exhibited the similar trend. Conclusions: Symptom profiles of irritability and the associated emotional and conduct problems in children with hfASD were similar to those of DMDD in the nonautistic population. Future studies are warranted to explore the underlying neurophysiological mechanisms of irritability between autistic and nonautistic children for further insight into the nature of irritability in autism.

Evaluating alternative models of youth externalizing using quantitative genetic analyses.

Interest has increased in the recent literature on characterizing psychopathology dimensionally in hierarchical models. One dimension of psychopathology that has received considerable attention is externalizing. Although extensively studied and well-characterized in late adolescents and adults, delineation of the externalizing spectrum in youth has lagged behind. As a complement to structural analyses of externalizing, in this study, we use quantitative genetic analyses of twin data to adjudicate among alternative models of youth externalizing that differ in granularity. Specifically, we compared model fit, estimates of genetic and environmental influences on the externalizing dimension, and the average, variability, and precision of genetic and environmental influences on individual symptoms due to the externalizing dimension, specific symptom dimensions, and unique etiological influences. Given that none of these criteria are definitive on their own, we looked to the confluence of these criteria to exclude particular models while highlighting others as leading contenders. We analyzed parent-report data on 38 externalizing symptoms from a population-representative, ethnically diverse sample of 883 youth twin pairs (51% female), who were on average 8.5 years old. Although models including an externalizing composite and attention deficit hyperactivity disorder, oppositional defiant disorder, and conduct disorder diagnoses and symptom dimensions showed similar heritability to latent variable models of externalizing, models that included latent dimensions of externalizing and more fine-grained symptom dimensions fit better and were more balanced in the magnitude of genetic and environmental influences on individual symptoms due to the externalizing dimension and specific symptom dimensions. Pending replication, these more granular and elaborated model(s) can be useful for advancing research on causes and outcomes of youth externalizing and its fine-grained specific components. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Revisiting stimulant use for emotional dysregulation in attention-deficit/hyperactivity disorder (ADHD).

INTRODUCTION: Emotional dysregulation (ED) symptoms are present in a considerable portion of patients with attention-deficit/hyperactivity disorder (ADHD). In recent years, an increasing number of studies investigated the effects of stimulant medications on ED in patients with ADHD. AREAS COVERED: A narrative review of the literature on stimulant treatment for ED is provided, including controlled and observational clinical studies conducted on pediatric and adult samples and neurobiological investigations. Positive effects of stimulants on irritability have been demonstrated in children. Comorbidity with disruptive behavior disorders (DBD) and disruptive mood dysregulation disorder does not prevent stimulant effectiveness. Methylphenidate has also been found to reduce temper problems, affective instability, and emotional over-reactivity in adults with ADHD, although with variable effect sizes. A variety of adverse emotional effects have been reported, especially at high doses and in special populations. However, several possible confounders of treatment-emergent ED have been highlighted. Finally, according to neuroimaging studies, stimulants may mitigate emotional processing anomalies associated with ADHD. EXPERT OPINION: The findings are consistent with models including ED within the core features of ADHD. Stimulant treatment should be prioritized over antipsychotics in ADHD-DBD. It remains to be elucidated whether other medications may be more effective in specific populations with ADHD and/or ED.