Toward a Developmental Nosology for Disruptive Mood Dysregulation Disorder in Early Childhood

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.

A Developmentally Informed Systematic Review and Meta-Analysis of the Strength of General Psychopathology in Childhood and Adolescence

Considerable support exists for higher-order dimensional conceptualizations of psychopathology in adults. A growing body of work has focused on understanding the structure of general and specific psychopathology in children and adolescents. No prior meta-analysis has examined whether the strength of the general psychopathology factor (p factor)-measured by explained common variance (ECV)-changes from childhood to adolescence. The primary objective of this multilevel meta-analysis was to determine whether general psychopathology strength changes across development (i.e. across ages) in childhood and adolescence. Several databases were searched in November 2021; 65 studies, with 110 effect sizes (ECV), nested within shared data sources, were identified. Included empirical studies used a factor analytic modeling approach that estimated latent factors for child/adolescent internalizing, externalizing, and optionally thought-disordered psychopathology, and a general factor. Studies spanned ages 2-17 years. Across ages, general psychopathology explained over half (~ 56%) of the reliable variance in symptoms of psychopathology. Age-moderation analyses revealed that general factor strength remained stable across ages, suggesting that general psychopathology strength does not significantly change across childhood to adolescence. Even if the structure of psychopathology changes with development, the prominence of general psychopathology across development has important implications for future research and intervention.

Future Directions: The Phenomenology of Irritable Mood and Outbursts: Hang Together or Hang Separately1

Recognition of the importance of irritable mood and outbursts has been increasing over the past several decades. This "Future Directions" aims to develop a set of recommendations for future research emphasizing that irritable mood and outbursts "hang together," but have important distinctions and thus also need to "hang separately." Outbursts that are the outcome of irritable mood may be quite different from outbursts that are the trigger or driving force that make youth and his/her environment miserable. What, then, is the relation between irritable mood and outbursts? As the field currently stands, we not only cannot answer this question, but we may also lack the tools to effectively do so. Here, we will propose recommendations for understanding the phenomenology of irritable mood and outbursts so that more directed and clinically useful assessment tools can be designed. We discuss the transdiagnostic and treatment implications that relate to improvements in measurement. We describe the need to do more than repurpose our current assessment tools, specifically interviews and rating scales, which were designed for different purposes. The future directions of the study and treatment of irritable mood and outbursts will require, among others, using universally accepted nomenclature, supporting the development of tools to measure the characteristics of each irritable mood and outbursts, understanding the effects of question order, informant, development and longitudinal course, and studying the ways in which outbursts and irritable mood respond to treatment.

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.

Systematic Review and Meta-Analysis: Early Irritability as a Transdiagnostic Neurodevelopmental Vulnerability to Later Mental Health Problems

OBJECTIVE

Irritability is a transdiagnostic indicator of child and adolescent internalizing and externalizing problems that is measurable from early life. The objective of this systematic review was to determine the strength of the association between irritability measured from 0 to 5 years and later internalizing and externalizing problems, to identify mediators and moderators of these relationships, and to explore whether the strength of the association varied according to irritability operationalization.

METHOD

Relevant studies published in peer-reviewed, English-language journals between the years 2000 and 2021 were sought from EMBASE, PsycINFO, MEDLINE, CINAHL, and ERIC. We synthesized studies that included a measure of irritability within the first 5 years of life and reported associations with later internalizing and/or externalizing problems. Methodological quality was assessed using the JBI-SUMARI Critical Appraisal Checklist.

RESULTS

Of 29,818 identified studies, 98 met inclusion criteria, with a total number of 932,229 participants. Meta-analysis was conducted on 70 studies (n = 831,913). Small, pooled associations were observed between infant irritability (0-12 months) and later internalizing (r = 0.14, 95% CI = 0.09, 0.20) and externalizing symptoms (r = 0.16, 95% CI = 0.11, 0.21) symptoms. For toddler/preschool irritability (13-60 months), small-to-moderate pooled associations were observed for internalizing (r = 0.21, 95% CI = 0.14, 0.28) and externalizing (r = 0.24, 95% CI = 0.18, 0.29) symptoms. These associations were not moderated by the lag between irritability and outcome assessment, although the strength of the associations varied according to irritability operationalization.

CONCLUSION

Early irritability is a consistent transdiagnostic predictor of internalizing and externalizing symptoms in childhood and adolescence. More work is required to understand how to accurately characterize irritability across this developmental period, and to understand mechanisms underlying the relationship between early irritability and later mental health problems.

DIVERSITY & INCLUSION STATEMENT

One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented racial and/or ethnic groups in science. One or more of the authors of this paper self-identifies as living with a disability. We actively worked to promote sex and gender balance in our author group. We actively worked to promote inclusion of historically underrepresented racial and/or ethnic groups in science in our author group.

STUDY PREREGISTRATION INFORMATION

Early irritability as a transdiagnostic neurodevelopmental vulnerability to early onset mental health problems: A systematic review; https://www.crd.york.ac.uk/prospero/; CRD42020214658.

Developmental Trajectories of Irritability across the Transition to Toddlerhood: Associations with Effortful Control and Psychopathology

Preschool-age irritability is a transdiagnostic marker of internalizing and externalizing problems. However, researchers have generally been reluctant to examine irritability within a clinically salient framework at younger ages due to some instability during the "terrible twos" period. Developmentally sensitive and dense measurements to capture intra- and inter-individual variability, as well as exploration of developmental processes that predict change, are needed. This study aimed to examine (1) the trajectories of irritability at the transition to toddlerhood (12-24 months of age) using repeated measures, (2) whether effortful control was associated with individual differences in level and growth rate of irritability, and (3) whether individual differences in the irritability trajectories were associated with later psychopathology. Families were recruited when the child was 12-18 months old (N = 333, 45.65% female). Mothers reported on their toddler's irritability at baseline and every two months until a follow-up laboratory assessment approximately one year later. Effortful control was measured at baseline. Clinical internalizing/externalizing symptoms were measured at the follow-up assessment. Hierarchical linear models revealed an increase in irritability over time, yet there was relatively little within-person variability. Effortful control was only associated with the level of irritability and not growth rate. Level of irritability was associated with internalizing, externalizing, and combined symptoms, but growth rate was not. Findings suggest intraindividual stability in irritability at the transition to toddlerhood and the possibility that screening for elevated irritability at toddler age is meaningful.

Advancing earlier transdiagnostic identification of mental health risk: A pragmatic approach at the transition to toddlerhood

OBJECTIVES

In light of the youth mental health crisis, as 1 in 5 children have a mental disorder diagnosis by age 3, identification of transdiagnostic behavioral vulnerability prior to impairing psychopathology must occur at an earlier phase of the clinical sequence. Here, we lay the groundwork for a pragmatic irritability measure to identify at-risk infant-toddlers.

METHODS

Data comprised N = 350 diverse infant-toddlers and their mothers assessed at ∼14 months old for irritability (Multidimensional Assessment Profiles- Temper Loss-Infant/Toddler (MAPS-TL-IT) and impairment (Early Childhood Irritability-Related Impairment Interview, E-CRI; and Family Life Impairment Scale (FLIS). Bimonthly follow-up surveys assessed impairment (FLIS) over the following year.

RESULTS

Stepwise logistic regression indicated that 5 MAPS-TL-IT items were most informative for differentiating concurrent impairment on the FLIS: "frustrated about small things"; "hit, bite, or kick during tantrums"; "trouble cheering up when grumpy"; "grumpy during fun activities" and "tantrums in public". With this summed score, Receiver Operating Characteristics analysis differentiating concurrent impairment on the E-CRI indicated good classification accuracy for (Area under the curve = 0.755, p < 0.05), with a cutoff of 5 maximizing sensitivity (71.4%) and specificity (70.6%). Elevated irritability on this MAPS-TL-IT clinically optimized screener increased likelihood of persistently elevated FLIS impairment trajectories over the following year more than fourfold (OR = 4.37; Confidence intervals = 2.40-7.97, p < 0.001).

CONCLUSIONS

Our findings represent the first step toward a pragmatic tool for screening for transdiagnostic mental health risk in toddlers, optimized for feasibility in clinical care. This has potential to strengthen resilience pathways via earlier identification of mental health risk and corollary prevention in toddlers.

Prevalence, stability, and predictive utility of the Multidimensional Assessment of Preschoolers Scales clinically optimized irritability score: Pragmatic early assessment of mental disorder risk

OBJECTIVES

Characterizing the scope and import of early childhood irritability is essential for real-world actualization of this reliable indicator of transdiagnostic mental health risk. Thus, we utilize pragmatic assessment to establish prevalence, stability, and predictive utility of clinically significant early childhood irritability.

METHODS

Data included two independent, diverse community samples of preschool age children (N = 1857; N = 1490), with a subset enriched for risk (N = 425) assessed longitudinally from early childhood through preadolescence (∼4-9 years old). A validated, brief (2-item) scale pragmatically assessed clinically significant irritability. In the longitudinal subsample, clinical interviews assessed internalizing/externalizing disorders.

RESULTS

One in five preschool-age children had clinically significant irritability, which was independently replicated. Irritability was highly stable through preadolescence. Children with versus without clinically significant early childhood irritability had greater odds of early onset, persistent internalizing/externalizing disorders. The pragmatic assessment effectively screened out low-risk children and identified 2/3 of children with early-onset, persistent psychopathology.

CONCLUSIONS

Clinically significant early childhood irritability prevalence is akin to the pediatric obesity epidemic and may warrant similar universal screening/intervention. Also, irritability's stability demonstrates the common guidance "they'll grow out of it" to be false. Finally, pragmatic irritability assessment has transdiagnostic predictive power and addresses a need for feasible measures to flag risk.

Does the apple fall far from the tree? Commentary on Hafeman et al., early indicators of bipolar risk in preschool offspring of parents with bipolar disorder

Comorbid externalizing and internalizing disorders are common in offspring of a parent with bipolar I or II disorder. In some cases, the symptoms are harbingers of future bipolar spectrum disorder. Even when they are not, they are likely to be impairing to the child. Clinicians need to be better informed about how the history leading up to mania/hypomania unfolds, and what comorbid disorders are impairing in and of themselves. More information is needed about the parents' psychopathology, course of illness and response to treatment. Until we have data on how to prevent bipolar disorder, the best course of action is to treat the child's current impairing symptoms and render the parent as asymptomatic as possible.

Do general and specific factors of preschool psychopathology predict preadolescent outcomes? A transdiagnostic hierarchical approach

BACKGROUND

Preschool psychiatric symptoms significantly increase the risk for long-term negative outcomes. Transdiagnostic hierarchical approaches that capture general ('p') and specific psychopathology dimensions are promising for understanding risk and predicting outcomes, but their predictive utility in young children is not well established. We delineated a hierarchical structure of preschool psychopathology dimensions and tested their ability to predict psychiatric disorders and functional impairment in preadolescence.

METHODS

Data for 1253 preschool children (mean age = 4.17, s.d. = 0.81) were drawn from three longitudinal studies using a similar methodology (one community sample, two psychopathology-enriched samples) and followed up into preadolescence, yielding a large and diverse sample. Exploratory factor models derived a hierarchical structure of general and specific factors using symptoms from the Preschool Age Psychiatric Assessment interview. Longitudinal analyses examined the prospective associations of preschool p and specific factors with preadolescent psychiatric disorders and functional impairment.

RESULTS

A hierarchical dimensional structure with a p factor at the top and up to six specific factors (distress, fear, separation anxiety, social anxiety, inattention-hyperactivity, oppositionality) emerged at preschool age. The p factor predicted all preadolescent disorders (ΔR2 = 0.04-0.15) and functional impairment (ΔR2 = 0.01-0.07) to a significantly greater extent than preschool psychiatric diagnoses and functioning. Specific dimensions provided additional predictive power for the majority of preadolescent outcomes (disorders: ΔR2 = 0.06-0.15; functional impairment: ΔR2 = 0.05-0.12).

CONCLUSIONS

Both general and specific dimensions of preschool psychopathology are useful for predicting clinical and functional outcomes almost a decade later. These findings highlight the value of transdiagnostic dimensions for predicting prognosis and as potential targets for early intervention and prevention.

Inhibitory Control in Early Childhood Aggression Subtypes: Mediation by Irritability

The present study tested irritability as a mediator of inhibitory control's (IC) associations with crossed form and function aggression subtypes over one year in early childhood (N = 300, M_age = 44.70 months, SD = 4.38 months). We hypothesized lower IC would predict increases in irritability, which would in turn predict increases in aggression overall (severity) and a predominance of reactive over proactive subtypes (directionality), and considered moderation by gender. Irritability mediated IC's relations in the predicted direction for physical severity for girls only and relational severity for both genders. Lower IC predicted increases in irritability, which in turn predicted increasing predominance of reactive over proactive physical and relational aggression. The predicted indirect effect was significant for physical but not relational directionality. Findings highlight the viability of directionality scores for disentangling these effects, and that developmental associations between IC, irritability, and reactive functions of aggression are evident in early childhood.

Finding a Needed Diagnostic Home for Children with Impulsive Aggression

Aggressive behavior is one of the most common reasons for referrals of youth to mental health treatment. While there are multiple publications describing different types of aggression in children, it remains challenging for clinicians to diagnose and treat aggressive youth, especially those with impulsively aggressive behaviors. The reason for this dilemma is that currently several psychiatric diagnoses include only some of the common symptoms of aggression in their criteria. However, no single diagnosis or diagnostic specifier adequately captures youth with impulsive aggression (IA). Here we review select current diagnostic categories, including behavior and mood disorders, and suggest that they do not provide an adequate description of youth with IA. We also specifically focus on the construct of IA as a distinct entity from other diagnoses and propose a set of initial, provisional diagnostic criteria based on the available evidence that describes youth with IA to use for future evaluation.

Narrative Review: Impairing Emotional Outbursts: What They Are and What We Should Do About Them

OBJECTIVE

Impairing emotional outbursts, defined by extreme anger or distress in response to relatively ordinary frustrations and disappointments, impact all mental health care systems, emergency departments, schools, and juvenile justice programs. However, the prevalence, outcome, and impact of outbursts are difficult to quantify because they are transdiagnostic and not explicitly defined by current diagnostic nosology. Research variably addresses outbursts under the rubrics of tantrums, anger, irritability, aggression, rage attacks, or emotional and behavioral dysregulation. Consistent methods for identifying and assessing impairing emotional outbursts across development or systems of care are lacking.

METHOD

The American Academy of Child and Adolescent Psychiatry Presidential Task Force (2019-2021) conducted a narrative review addressing impairing emotional outbursts within the limitations of the existing literature and independent of diagnosis.

RESULTS

Extrapolating from the existing literature, best estimates suggest that outbursts occur in 4%-10% of community children (preschoolers through adolescents). Impairing emotional outbursts may respond to successful treatment of the primary disorder, especially for some children with attention-deficit/hyperactivity disorder whose medications have been optimized. However, outbursts are generally multi-determined and often represent maladaptive or deficient coping strategies and responses.

CONCLUSION

Evidence-based strategies are necessary to address factors that trigger, reinforce, or excuse the behaviors and to enhance problem-solving skills. Currently available interventions yield only modest effect sizes for treatment effect. More specific definitions and measures are needed to track and quantify outbursts and to design and assess the effectiveness of interventions. Better treatments are clearly needed.

Irritability in early to middle childhood: Cross-sectional and longitudinal associations with resting state amygdala and ventral striatum connectivity

BACKGROUND

Irritability is a common symptom that may affect children's brain development. This study aims to (1) characterize age-dependent and age-independent neural correlates of irritability in a sample of 4-8 year old children, and (2) examine early irritability as a predictor of change in brain connectivity over time.

METHODS

Typically developing children, ages 4-8 years, with varying levels of irritability were included. Resting state fMRI and parent-rated irritability (via Child Behavior Checklist; CBCL) were collected at up to three time points, resulting in a cross-sectional sample at baseline (N = 176, M = 6.27, SD = 1.49), and two subsamples consisting of children who were either 4 or 6 years old at baseline that were followed longitudinally for two additional timepoints, one- and two-years post-baseline. That is, a "younger" cohort (age 4 at baseline, n = 34, M age = 4.44, SD = 0.25) and an "older" cohort (age 6 at baseline, n = 29, M age = 6.50, SD = 0.30). Across our exploratory analyses, we examined how irritability related to seed-based intrinsic connectivity via whole-brain connectivity ANCOVAs using the left and right amygdala, and left and right ventral striatum as seed regions.

RESULTS

Cross-sectionally, higher levels of irritability were associated with greater amygdala connectivity with the posterior cingulate, controlling for child age. No age-dependent effects were observed in the cross-sectional analyses. Longitudinal analyses in the younger cohort revealed that early higher vs. lower levels of irritability, controlling for later irritability, were associated with decreases in amygdala and ventral striatum connectivity with multiple frontal and parietal regions over time. There were no significant findings in the older cohort.

CONCLUSIONS

Findings suggest that irritability is related to altered neural connectivity during rest regardless of age in early to middle childhood and that early childhood irritability may be linked to altered changes in neural connectivity over time. Understanding how childhood irritability interacts with neural processes can inform pathophysiological models of pediatric irritability and the development of targeted mechanistic interventions.

Roads Diverged: Developmental Trajectories of Irritability From Toddlerhood Through Adolescence

OBJECTIVE

Irritability is a dimensional trait that manifests from early life and is a robust transdiagnostic risk factor for psychopathology and impairment. A large, national dataset was leveraged to identify and broadly characterize trajectories from toddlerhood through adolescence, which is crucial for timely, targeted interventions.

METHOD

Data on irritability and a broad array of potential factors affecting irritability development from 4,462 children assessed longitudinally at ages 3, 5, 9, and 15 were included. Latent class growth models identified groups of children based on their nonlinear irritability trajectories from toddlerhood to adolescence. LASSO regression then identified key characteristics differentiating trajectory groups.

RESULTS

Five distinct irritability trajectories were identified, two of which were stable, maintaining medium or high irritability from age 3 to 15. Three trajectories showed undulating change over development, with an inflection point at the transition to adolescence (age 9): Most children had consistently low irritability. Two smaller groups started with high irritability at age 3 but diverged, sharply decreasing or increasing until a turning point at age 9. Developmental patterning of harsh/neglectful parenting and child internalizing symptoms most strongly differentiated trajectory groups. Sociodemographic characteristics, attachment style, neighborhood support, cognitive functioning, and genetic variation also differentiated trajectories.

CONCLUSION

The results demonstrated the importance of the transition to adolescence as a critical inflection point for youths with fluctuating irritability trajectories. Identifying these patterns and multiple malleable factors associated with stably high or rising trajectories is an important step toward targeted interventions for the most vulnerable subgroups.

DIVERSITY & INCLUSION STATEMENT

We worked to ensure sex and gender balance in the recruitment of human participants. We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented racial and/or ethnic groups in science. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented sexual and/or gender groups in science. One or more of the authors of this paper self-identifies as living with a disability. One or more of the authors of this paper received support from a program designed to increase minority representation in science. We actively worked to promote sex and gender balance in our author group. We actively worked to promote inclusion of historically underrepresented racial and/or ethnic groups in science in our author group.

Differential diagnoses of irritability and temper loss in a 6-year-old

Irritability and temper loss are common concerns among young children seen for mental health diagnostic evaluations and represent features of nearly a dozen childhood mental health conditions. Thus, careful assessment of irritability and temper loss is essential for informing case conceptualization, diagnosis, and treatment recommendations. The current case study provides a clinical description of a 6-year-old Black male ("Tyler") seen in a tertiary pediatric medical center for concerns related to significant inattention, hyperactivity, impulsivity, oppositional behaviors, irritability, and severe temper loss displayed at home and school. The clinical description summarizes findings from rating scales and diagnostic evaluations, case conceptualization, as well as treatment recommendations. Detailed suggestions for clinicians regarding strategies for assessing irritability and temper loss and questions to consider when seeking clarification to inform differential diagnoses are provided.

Temper Tantrums in Toddlers and Preschoolers: Longitudinal Associations with Adjustment Problems

OBJECTIVE

We examined parent reports of temper tantrum characteristics (e.g., frequency, duration, and behavioral profile) in toddlers and preschoolers and their longitudinal association with internalizing and externalizing adjustment problems.

METHODS

Parents of 1- to 5-year-olds (N = 861, M age = 36 months, 47% girls) reported their child's temper tantrum frequency, duration, and behaviors. A subsample also reported on their child's tantrums and adjustment problems 1 year later (n = 252). We first compared the distribution of temper tantrum frequency and duration for different ages. Next, we examined which factors underlie the tantrum behaviors and whether behavioral profiles could be distinguished based on configurations of these factors within children. Finally, we performed regression analyses predicting internalizing and externalizing adjustment problems by temper tantrum frequency, duration, and behavioral profile, controlling for child sex and age.

RESULTS

Chi-square tests indicated that overall, tantrum frequency declined, whereas tantrum duration increased across the 1- to 5-year age range. We found that based on 4 tantrum behavior factors (anger, distress, aggression, and self-injurious behavior), 3 profiles characterized the tantrum behavior of children in the sample: a low-intensity profile (26%), a moderate-intensity profile (32%), and a high aggressive/self-injurious profile (42%). More frequent tantrums predicted more externalizing problems, whereas longer tantrum duration predicted internalizing problems. The high aggressive/self-injurious profile predicted adjustment problems above and beyond tantrum duration and frequency.

CONCLUSION

Parent reports of different tantrum characteristics are uniquely predictive of different types of problems and may each be important to include in screening efforts for adjustment problems in young children.

Developmental patterning of irritability enhances prediction of psychopathology in preadolescence: Improving RDoC with developmental science

The transdiagnostic importance of irritability in psychopathology has been demonstrated. However, the contribution of developmentally unfolding irritability patterns to specific clinical and neural outcomes remains an important and unanswered question. To address this gap in the literature, irritability patterns of 110 youth from a large, diverse cohort were assessed at preschool age and again at early school age (∼2.5 years later) with a dimensional irritability scale designed to capture the normal:abnormal spectrum. At preadolescence (∼6 years later), clinical outcomes (internalizing/externalizing symptoms) derived from a semistructured clinical interview and neural outcomes (characterized as gray-matter-volume abnormalities) were assessed. For clinical outcomes, preschool-age irritability alone was a transdiagnostic predictor of internalizing and externalizing symptoms at preadolescence. However, in a model including both preschool and early school age, irritability provided greater specificity, suggesting that higher irritability at early school age related to elevated preadolescent externalizing but not internalizing symptoms. In terms of neural outcomes, elevated preschool irritability did not predict preadolescent gray-matter-volume abnormality; however, irritability at early school age demonstrated an interactive effect among regions, with reduced volume in preadolescence emotional regions (e.g., amygdala, medial orbitofrontal cortex) and increased volume in other regions (e.g., cerebellum). These complex patterns highlight the contribution of a developmentally informed approach, the National Institute of Mental Health's Research Domain Criteria (RDoC) approach, to yield transdiagnostic phenotypes and multiple units of analysis. Capturing these individual differences and developmental heterogeneity can provide critical insight into the unfolding of mechanisms underlying emerging psychopathology. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Executive functioning moderates neural mechanisms of irritability during reward processing in youth

Pediatric irritability is the most robust indicator of transdiagnostic psychopathology risk. It is associated with altered neural reward processing, including neural networks related to cognitive control, and better cognitive control has been hypothesized to mitigate irritability. We evaluated the relationship of executive functioning (EF) with irritability-related neural correlates of reward processing in youths with varying levels of irritability. Participants (N = 51, mean age=13.80 years, SD=1.94) completed a monetary incentive delay task during multiband fMRI acquisition. Irritability and EF were measured via the Affective Reactivity Index and the NIH Toolbox cognition battery, respectively. Whole-brain analyses, controlling for age, examined the moderating role of EF on irritability-related brain activation and connectivity (seeds: striatum, amygdala) during reward anticipation and performance feedback. Irritability-related neural patterns during reward processing depended on EF, in occipital areas during reward anticipation and limbic, frontal, and temporal networks during performance feedback. Higher irritability combined with higher EF was associated with neural patterns opposite to those observed for higher irritability with lower co-occurring EF. Although preliminary, findings suggest that EF may buffer irritability-related reward processing deficits. Additionally, individual differences in EF and their relation to irritability may be related to varied etiologic mechanisms of irritability with important implications for personalized prevention and intervention.

Measuring PROMIS® Emotional Distress in Early Childhood

OBJECTIVE

Create and validate developmentally sensitive parent-report measures of emotional distress for children ages 1-5 years that conceptually align with the Patient-Reported Outcome Measurement Information System (PROMIS®) pediatric measures.

METHODS

Initial items were generated based on expert and parent input regarding core components of emotional distress in early childhood and review of theoretical and empirical work in this domain. Items were psychometrically tested using data from two waves of panel surveys. Item response theory (IRT) was applied to develop item calibration parameters (Wave 1), and scores were centered on a general U.S. population sample (Wave 2). Final PROMIS early childhood (EC) instruments were compared with existing measures of related constructs to establish construct validity.

RESULTS

Experts and parents confirmed the content validity of the existing PROMIS Pediatric emotional distress domains (i.e., anger, anxiety, and depressive symptoms) as developmentally salient for young children. Existing items were adapted and expanded for early childhood by employing best practices from developmental measurement science. Item banks as well as 4- and 8-item short forms, free from differential item functioning across sex and age, were constructed for the three domains based on rigorous IRT analyses. Correlations with subscales from previously validated measures provided further evidence of construct validity.

CONCLUSIONS

The PROMIS EC Anger/Irritability, Anxiety, and Depressive Symptoms measures demonstrated good reliability and initial evidence of validity for use in early childhood. This is an important contribution to advancing brief, efficient measurement of emotional distress in young children, closing a developmental gap in PROMIS pediatric emotional distress assessment.

Translating RDoC to Real-World Impact in Developmental Psychopathology: A Neurodevelopmental Framework for Application of Mental Health Risk Calculators

The National Institute of Mental Health Research Domain Criteria's (RDoC) has prompted a paradigm shift from categorical psychiatric disorders to considering multiple levels of vulnerability for probabilistic risk of disorder. However, the lack of neurodevelopmentally-based tools for clinical decision-making has limited RDoC's real-world impact. Integration with developmental psychopathology principles and statistical methods actualize the clinical implementation of RDoC to inform neurodevelopmental risk. In this conceptual paper, we introduce the probabilistic mental health risk calculator as an innovation for such translation and lay out a research agenda for generating an RDoC- and developmentally-informed paradigm that could be applied to predict a range of developmental psychopathologies from early childhood to young adulthood. We discuss methods that weigh the incremental utility for prediction based on intensity and burden of assessment, the addition of developmental change patterns, considerations for assessing outcomes, and integrative data approaches. Throughout, we illustrate the risk calculator approach with different neurodevelopmental pathways and phenotypes. Finally, we discuss real-world implementation of these methods for improving early identification and prevention of developmental psychopathology. We propose that mental health risk calculators can build a needed bridge between RDoC's multiple units of analysis and developmental science.

Chronic Irritability in Youth: A Reprise on Challenges and Opportunities Toward Meeting Unmet Clinical Needs

This commentary focuses on irritability, one subtype of emotion dysregulation. We review literature demonstrating that irritability is not a developmental phenotype of bipolar disorder, but is longitudinally associated with unipolar depression and anxiety and genetically associated with unipolar depression, anxiety, and attention-deficit hyperactivity disorder. We describe how irritability is amenable to translational research, in part because of the relevance of frustrative nonreward, a model developed in rodents, to human irritability. Last, we demonstrate how such research has suggested a novel exposure-based intervention for irritability.

The Irritable and Oppositional Dimensions of Oppositional Defiant Disorder: Integral Factors in the Explanation of Affective and Behavioral Psychopathology

Oppositional defiant disorder includes distinct but inseparable dimensions of chronic irritability and oppositional behavior. The dimensions have been identified in early childhood to adulthood, and show discriminant associations with internalizing and externalizing psychopathology. The introduction of disruptive mood dysregulation disorders and the requirements that it take precedence over oppositional defiant disorder diagnostically are not supported by evidence and introduce confusion about the structure and linkages of irritability and oppositional behavior, and obscure the importance of the behavioral dimension in explaining and predicting poor outcomes. A dimensional framework with irritability, oppositionality, callous-unemotional traits, and aggression may more fully describe antisocial outcomes.

Measuring Irritability in Early Childhood: A Psychometric Evaluation of the Affective Reactivity Index in a Clinical Sample of 3- to 8-Year-Old Children

The parent-report Affective Reactivity Index (ARI-P) is the most studied brief scale specifically developed to assess irritability, but relatively little is known about its performance in early childhood (i.e., ≤8 years). Support in such populations is particularly important given developmental shifts in what constitutes normative irritability across childhood. We examined the performance of the ARI-P in a diverse, treatment-seeking sample of children ages 3 to 8 years (N = 115; mean age = 5.56 years; 58.4% from ethnic/racial minority backgrounds). In this sample, confirmatory factor analysis supported the single-factor structure of the ARI-P previously identified with older youth. ARI-P scores showed large associations with another irritability index, as well as small-to-large associations with aggression, anxiety, depression, and attention problems, supporting the convergent and concurrent validity of the ARI-P when used with children in this younger age range. Findings support the ARI-P as a promising parent-report tool for assessing irritability in early childhood, particularly in clinical samples.

Drs. Wiggins and Wakschlag Reply

We thank Benarous et al. for their recognition of the necessity of a developmental view on disruptive mood dysregulation disorder (DMDD) and for their thoughtful comments.¹ Indeed, a growing science base challenges the "old thinking" that developmental instability precludes earlier identification of DMDD syndromes. Notably, our paper was designed to promote a move toward a dimensional approach, which ultimately would obviate the need to make "you have it or you don't" decisions. In the short term, because real-world clinical decision making still rests on the presence or absence of DSM syndromes, our goal was to generate a developmentally informed evidence base for earlier identification and prevention of early-onset clinically significant irritability.

Editorial: A Call for Developmental Psychopathology Approaches to Diagnostic Nosology

The publication of DSM-5 came with a number of significant advances, including shifts in disorder classifications and a new focus on dimensional assessment.¹ It also introduced disruptive mood dysregulation disorder (DMDD), which was met with some criticism and concern. Although there was research to support the establishment of this new diagnosis aimed at improving classification of children and adolescents with persistent and impairing irritability,² specific symptoms and definitions of frequency and impairment were not as empirically supported, and concerns arose regarding validity and reliability.³ The introduction of new diagnoses is a complex endeavor, particularly for disorders affecting children and adolescents, which require consideration of the immense neural, cognitive, and emotional changes occurring during this developmental period. Rigorous approaches grounded in developmental psychopathology are needed to establish a meaningful and clinically useful set of symptoms and associated characteristics. This is the approach that Wiggins et al.⁴ take to address the applicability of the DMDD diagnosis for children below the age of 6 years. Although this minimum age was included in DSM-5 to prevent unwarranted labeling of young children for whom temper outbursts are common,⁵ it fails to consider growing evidence of impairing irritability in preschoolers and limits identification of children who would benefit from early interventions. In response to this, these authors take a comprehensive bottom-up approach to empirically identify symptoms and to define limits of clinical severity, tailored specifically to preschool-aged children. As such, this study serves as a model of how to develop and to refine the diagnostic nosology of child psychiatric disorders.

Editorial: Defining the Clinical Boundary of Disruptive Mood Dysregulation Disorder Symptoms in Youth

Disruptive mood dysregulation disorder (DMDD) is a novel diagnosis emerging from a continuing discourse on the best diagnostic home for children with severe, chronic irritability. DMDD emerged from a research diagnosis that was developed to test the hypothesis that severe, chronic irritability is a developmental phenotype of pediatric bipolar disorder.¹ That is, such irritability is a phenomenon that emerges prior to a hypo/manic episode that defines bipolar disorder. For many, such irritability in conjunction with attention-deficit/hyperactivity disorder (ADHD) symptoms had been treated as a prodrome of bipolar disorder. Although this line of research did not establish a deterministic association between the DMDD syndrome and later bipolar disorder, it did provide guidance for assessing the risk of irritability for later bipolar disorder.² Among the outcomes was the introduction of DMDD as a new diagnosis in DSM-5. It is defined by 2 core symptoms-temper outbursts and irritable/angry mood-the 2 major features of irritability. However, what qualifies as DMDD-level irritable mood and temper outbursts is unclear, and, unlike other mood disorders, no ancillary symptom criteria are available to establish a diagnosis of DMDD. Through the example of the relationship between DMDD and ODD, we will illustrate the clinical impact of this lack of clarity and describe the current efforts to establish a developmentally sensitive clinical nosology for irritability.

Moving the dial on prenatal stress mechanisms of neurodevelopmental vulnerability to mental health problems: A personalized prevention proof of concept

Prenatal stress exposure increases vulnerability to virtually all forms of psychopathology. Based on this robust evidence base, we propose a "Mental Health, Earlier" paradigm shift for prenatal stress research, which moves from the documentation of stress-related outcomes to their prevention, with a focus on infant neurodevelopmental indicators of vulnerability to subsequent mental health problems. Achieving this requires an expansive team science approach. As an exemplar, we introduce the Promoting Healthy Brain Project (PHBP), a randomized trial testing the impact of the Wellness-4-2 personalized prenatal stress-reduction intervention on stress-related alterations in infant neurodevelopmental trajectories in the first year of life. Wellness-4-2 utilizes bio-integrated stress monitoring for just-in-time adaptive intervention. We highlight unique challenges and opportunities this novel team science approach presents in synergizing expertise across predictive analytics, bioengineering, health information technology, prevention science, maternal-fetal medicine, neonatology, pediatrics, and neurodevelopmental science. We discuss how innovations across many areas of study facilitate this personalized preventive approach, using developmentally sensitive brain and behavioral methods to investigate whether altering children's adverse gestational exposures, i.e., maternal stress in the womb, can improve their mental health outlooks. In so doing, we seek to propel developmental SEED research towards preventive applications with the potential to reduce the pernicious effect of prenatal stress on neurodevelopment, mental health, and wellbeing.

Principles for Guiding the Selection of Early Childhood Neurodevelopmental Risk and Resilience Measures: HEALthy Brain and Child Development Study as an Exemplar

The vast individual differences in the developmental origins of risk and resilience pathways combined with sophisticated capabilities of big data science increasingly point to the imperative of large, neurodevelopmental consortia to capture population heterogeneity and key variations in developmental trajectories. At the same time, such large-scale population-based designs involving multiple independent sites also must weigh competing demands. For example, the need for efficient, scalable assessment strategies must be balanced with the need for nuanced, developmentally sensitive phenotyping optimized for linkage to neural mechanisms and specification of common and distinct exposure pathways. Standardized epidemiologic batteries designed for this purpose such as PhenX (consensus measures for Phenotypes and eXposures) and the National Institutes of Health (NIH) Toolbox provide excellent "off the shelf" assessment tools that are well-validated and enable cross-study comparability. However, these standardized toolkits can also constrain ability to leverage advances in neurodevelopmental measurement over time, at times disproportionately advantaging established measures. In addition, individual consortia often expend exhaustive effort "reinventing the wheel," which is inefficient and fails to fully maximize potential synergies with other like initiatives. To address these issues, this paper lays forth an early childhood neurodevelopmental assessment strategy, guided by a set of principles synthesizing developmental and pragmatic considerations generated by the Neurodevelopmental Workgroup of the HEALthy Brain and Child Development (HBCD) Planning Consortium. These principles emphasize characterization of both risk- and resilience-promoting processes. Specific measurement recommendations to HBCD are provided to illustrate application. However, principles are intended as a guiding framework to transcend any particular initiative as a broad neurodevelopmentally informed, early childhood assessment strategy for large-scale consortia science.

Amygdala subnuclei volume in bipolar spectrum disorders: Insights from diffusion-based subsegmentation and a high-risk design

Amygdala abnormalities are widely documented in bipolar spectrum disorders (BSD). Amygdala volume typically is measured after BSD onset; thus, it is not known whether amygdala abnormalities predict BSD risk or relate to the disorder. Additionally, past literature often treated the amygdala as a homogeneous structure, and did not consider its distinct subnuclei and their differential connectivity to other brain regions. To address these issues, we used a behavioral high‐risk design and diffusion‐based subsegmentation to examine amygdala subnuclei among medication‐free individuals with, and at risk for, BSD. The behavioral high‐risk design (N = 114) included low‐risk (N = 37), high‐risk (N = 47), and BSD groups (N = 30). Diffusion‐based subsegmentation of the amygdala was conducted to determine whether amygdala volume differences related to particular subnuclei. Individuals with a BSD diagnosis showed greater whole, bilateral amygdala volume compared to Low‐Risk individuals. Examination of subnuclei revealed that the BSD group had larger volumes compared to the High‐Risk group in both the left medial and central subnuclei, and showed larger volume in the right lateral subnucleus compared to the Low‐Risk group. Within the BSD group, specific amygdala subnuclei volumes related to time since first episode onset and number of lifetime episodes. Taken together, whole amygdala volume analyses replicated past findings of enlargement in BSD, but did not detect abnormalities in the high‐risk group. Examination of subnuclei volumes detected differences in volume between the high‐risk and BSD groups that were missed in the whole amygdala volume. Results have implications for understanding amygdala abnormalities among individuals with, and at risk for, a BSD.