Stability of Disruptive Mood Dysregulation Disorder Symptoms (Irritable-Angry Mood and Temper Outbursts) Throughout Childhood and Adolescence in a General Population Sample

Exploring temperament and sleep patterns in disruptive mood dysregulation disorder among children and adolescents: implications for clinical practice

BACKGROUND

Disruptive Mood Dysregulation Disorder (DMDD), characterized by severe irritability and temper outbursts, is a relatively new diagnosis included in the DSM-5. The study aimed to investigate the clinical characteristics, temperament, comorbidities, medication use, and sleep quality of children and adolescents diagnosed with DMDD and compare them with Major Depressive Disorder (MDD).

METHODS

A total of 233 participants (DMDD: n = 106; MDD: n = 127) were assessed using the K-SADS-PL. Evaluation tools included the Children's Temperament and Character Inventory, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Strengths and Difficulties Child and Parent Form, Children's Depression Inventory for children, and sociodemographic form.

RESULTS

The DMDD group scored significantly lower in harm avoidance, reward dependence, and cooperation than the MDD group (p ≤ 0.001, p ≤ 0.02, p ≤ 0.002, respectively). DMDD exhibits significantly lower levels of social skill-related temperament traits, such as empathy, compassion, and helpfulness. Furthermore, a higher proportion of patients in the DMDD group received antipsychotic, mood stabilizer, and stimulant medications during treatment.

CONCLUSION

Children and adolescents diagnosed with DMDD demonstrated significantly lower scores in anticipatory worry, fear of uncertainty, shyness, fatigability, sentimentality, dependence, empathy, and helpfulness compared to those with MDD. Conversely, they exhibited higher levels of impulsiveness, disorderliness, and self-acceptance. These findings underscore the necessity of evaluating and enhancing social skills and reward sensitivity in the clinical management of DMDD, as these distinct psychological and behavioral profiles suggest the need for more tailored therapeutic approaches.

Assessment of affective dysregulation in children: development and evaluation of a semi-structured interview for parents and for children

BACKGROUND

Children with affective dysregulation (AD) show an excessive reactivity to emotionally positive or negative stimuli, typically manifesting in chronic irritability, severe temper tantrums, and sudden mood swings. AD shows a large overlap with externalizing and internalizing disorders. Given its transdiagnostic nature, AD cannot be reliably and validly captured only by diagnostic categories such as disruptive mood dysregulation disorder (DMDD). Therefore, this study aimed to evaluate two semi-structured clinical interviews-one for parents and one for children.

METHODS

Both interviews were developed based on existing measures that capture particular aspects of AD. We analyzed internal consistencies and interrater agreement to evaluate their reliability. Furthermore, we analyzed factor loadings in an exploratory factor analysis, differences in interview scores between children with and without co-occurring internalizing and externalizing disorders, and associations with other measures of AD and of AD-related constructs. The evaluation was performed in a screened community sample of children aged 8-12 years (n = 445). Interrater reliability was additionally analyzed in an outpatient sample of children aged 8-12 years (n = 27).

RESULTS

Overall, internal consistency was acceptable to good. In both samples, we found moderate to excellent interrater reliability on a dimensional level. Interrater agreement for the dichotomous diagnosis DMDD was substantial to perfect. In the exploratory factor analysis, almost all factor loadings were acceptable. Children with a diagnosis of disruptive disorder, attention-deficit/hyperactivity disorder, or any disorder (disruptive disorder, attention-deficit/hyperactivity disorder, and depressive disorder) showed higher scores on the DADYS interviews than children without these disorders. The correlation analyses revealed the strongest associations with other measures of AD and measures of AD-specific functional impairment. Moreover, we found moderate to very large associations with internalizing and externalizing symptoms and moderate to large associations with emotion regulation strategies and health-related quality of life.

CONCLUSIONS

The analyses of internal consistency and interrater agreement support the reliability of both clinical interviews. Furthermore, exploratory factor analysis, discriminant analyses, and correlation analyses support the interviews' factorial, discriminant, concurrent, convergent, and divergent validity. The interviews might thus contribute to the reliable and valid identification of children with AD and the assessment of treatment responses.

TRIAL REGISTRATION

ADOPT Online: German Clinical Trials Register (DRKS) DRKS00014963. Registered 27 June 2018.

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.

Screening for affective dysregulation in school-aged children: relationship with comprehensive measures of affective dysregulation and related mental disorders

Affective dysregulation (AD) is characterized by irritability, severe temper outbursts, anger, and unpredictable mood swings, and is typically classified as a transdiagnostic entity. A reliable and valid measure is needed to adequately identify children at risk of AD. This study sought to validate a parent-rated screening questionnaire, which is part of the comprehensive Diagnostic Tool for Affective Dysregulation in Children (DADYS-Screen), by analyzing relationships with comprehensive measures of AD and related mental disorders in a community sample of children with and without AD. The sample comprised 1114 children aged 8-12 years and their parents. We used clinical, parent, and child ratings for our analyses. Across all raters, the DADYS-Screen showed large correlations with comprehensive measures of AD. As expected, correlations were stronger for measures of externalizing symptoms than for measures of internalizing symptoms. Moreover, we found negative associations with emotion regulation strategies and health-related quality of life. In receiver operating characteristic (ROC) analyses, the DADYS-Screen adequately identified children with AD and provided an optimal cut-off. We conclude that the DADYS-Screen appears to be a reliable and valid measure to identify school-aged children at risk of AD.

Validation of the Arabic version of the brief irritability test (Ar-BITe) in non-clinical adolescents

BACKGROUND

Despite the substantial clinical relevance of irritability in the development and maintenance of several mental disorders and its negative effects on functioning, no valid and reliable measures are available yet to identify the presence and consequences of irritability as a distinct construct among the Arabic-speaking populations. To bridge this gap, and help advance this field in the under-researched Arab region, we aimed to validate an Arabic-language version of the Brief Irritability Test (BITe).

METHODS

Eligible participants were native Arabic-speaking non-clinical adolescents from Lebanon; 527 participants aged 15.73 ± 1.81 years (56% females) completed the survey.

RESULTS

Utilizing the Confirmatory Factor Analysis approach, we found that the five items of the Arabic BITe loaded into a single factor structure. The scale showed excellent reliability, as both Cronbach's alpha and McDonald's omega coefficient values were of 0.88. Multi-group analyses showed invariance across sex groups in our sample at the configural, metric, and scalar levels. Female adolescents exhibited higher BITe scores than their male counterparts (14.01 vs. 13.25), but this difference did not reach the statistical significance. Good concurrent validity was supported based on positive correlations between irritability scores and measures of aggression, anger and hostility (r Pearson's coefficients ranging from 0.35 to 0.42), as well as positive correlations with insomnia symptoms scores.

CONCLUSION

The present findings allow us to conclude that the Arabic version of the BITe is a unidimensional, reliable, valid, brief, and economic self-report measure of the irritability construct for both male and female Arabic-speakers. Providing an Arabic validated version of the BITe will hopefully foster the research efforts of the Arab scientific community in this area, and promote the implementation of timely, evidence-informed and culturally-sensitive mental health interventions that appropriately address irritability-related problems and consequences among Arab young populations.

Impact of the COVID-19 pandemic on children with and without affective dysregulation and their families

Analyzing COVID-19-related stress in children with affective dysregulation (AD) seems especially interesting, as these children typically show heightened reactivity to potential stressors and an increased use of maladaptive emotion regulation strategies. Children in out-of-home care often show similar characteristics to those with AD. Since COVID-19 has led to interruptions in psychotherapy for children with mental health problems and to potentially reduced resources to implement treatment strategies in daily life in families or in out-of-home care, these children might show a particularly strong increase in stress levels. In this study, 512 families of children without AD and 269 families of children with AD reported on COVID-19-related stress. The sample comprised screened community, clinical, and out-of-home care samples. Sociodemographic factors, characteristics of child and caregiver before the pandemic, and perceived change in external conditions due to the pandemic were examined as potential risk or protective factors. Interestingly, only small differences emerged between families of children with and without AD or between subsamples: families of children with AD and families in out-of-home care were affected slightly more, but in few domains. Improvements and deteriorations in treatment-related effects balanced each other out. Overall, the most stable and strongest risk factor for COVID-19-related stress was perceived negative change in external conditions-particularly family conditions and leisure options. Additionally, caregiver characteristics emerged as risk factors across most models. Actions to support families during the pandemic should, therefore, facilitate external conditions and focus on caregiver characteristic to reduce familial COVID-19-related stress. Trial registration: German Clinical Trials Register (DRKS), ADOPT Online: DRKS00014963 registered 27 June 2018, ADOPT Treatment: DRKS00013317 registered 27 September 2018, ADOPT Institution: DRKS00014581 registered 04 July 2018.

The Feasibility, Acceptability, and Efficacy of Positive Search Training for Irritable Youth: A Single-Case Experimental Design

Although irritability is common in youth, research on treatment is in its infancy. Threat biases are more pronounced in irritable compared to low irritable youth, similar to evidence found in anxious youth. Therefore, interventions targeting these biases may be promising for reducing irritability. This study utilised a multiple baseline case series design to determine the feasibility, acceptability, and efficacy of positive search training (PST) for irritable children. Three children were included who met criteria for a principal diagnosis of Disruptive Mood Dysregulation Disorder (DMDD), and a secondary diagnosis of Attention Deficit Hyperactivity Disorder (ADHD) or Major Depressive Disorder (MDD). PST was feasible with two of the three participants; one child refused to continue after one session. For the two participants who completed PST, acceptability was stable with moderate-to-high ratings of engagement and enjoyment, and high and stable treatment-relevant verbalisations of the key strategies. Both cases showed declines in DMDD severity across treatment and no longer met criteria at post-treatment. Both participants met criteria for Oppositional Defiant Disorder (ODD) at post-treatment (considered less severe for irritability than DMDD). Declines in parent-reported irritability occurred for both cases, however some returns to baseline were observed. Overall, PST for irritable youth shows promise as an acceptable and feasible intervention. Further studies are needed combining PST with strategies for secondary diagnoses, given its high comorbidity with disruptive behaviour disorders.

The DADYS-Screen: Development and Evaluation of a Screening Tool for Affective Dysregulation in Children

Affective dysregulation (AD) in children is characterized by persistent irritability and severe temper outbursts. This study developed and evaluated a screening questionnaire for AD in children. The development included the generation of an initial item pool from existing instruments, a Delphi rating of experts, focus groups with experts and parents, and psychometric analyses of clinical and population-based samples. Based on data of a large community-based study, the final screening questionnaire was developed (n = 771; 49.7 % female; age M = 10.02 years; SD = 1.34) and evaluated (n = 8,974; 48.7 % female; age M = 10.00 years; SD = 1.38) with methods from classical test theory and item response theory. The developed DADYS-Screen (Diagnostic Tool for Affective Dysregulation in Children-Screening Questionnaire) includes 12 items with good psychometric properties and scale characteristics including a good fit to a one-factorial model in comparison to the baseline model, although only a "mediocre" fit according to the root mean square error of approximation (RMSEA). Results could be confirmed using a second and larger data set. Overall, the DADYS-Screen is able to identify children with AD, although it needs further investigation using clinical data.

Investigating the associations between irritability and hot and cool executive functioning in those with ADHD

BACKGROUND

Irritability is especially pertinent to those with Attention Deficit Hyperactivity Disorder (ADHD) as it is highly prevalent and associated with a more severe clinical presentation and poorer longitudinal outcomes. Preliminary evidence suggests that top-down cognitive processes taking place in emotional contexts (i.e., hot executive functions) as opposed to those evoked in abstract scenarios (i.e., cool executive functions) may be relevant to the presentation of irritability in ADHD. This study explored the cognitive mechanisms underlying irritability in young people with ADHD, hypothesising that irritability would be associated with hot, but not cool, executive function impairments.

METHODS

Our sample included 219 individuals with ADHD. A composite irritability score was derived extracting items from a parent interview, with scores ranging from 0 to 5. Associations were investigated using linear regression analyses, between irritability and four hot tasks measuring sensitivity to risk, risk-taking behaviour following reward or punishment, acceptance of reward delay and reaction to unfair behaviour from others, and two cool tasks measuring set-shifting and motor inhibition.

RESULTS

As hypothesised, there were no significant associations between irritability and cool executive functions in those with ADHD; however, contrary to expectations, there was also no significant evidence that hot executive functions were associated with irritability.

CONCLUSIONS

These results, in a large well characterised sample and using a comprehensive task battery, suggest that the variation in irritability in those with ADHD may not be associated with differences in hot or cool executive function performance.

Is Irritability a Top Problem in Youth Mental Health Care? A Multi-informant, Multi-method Investigation

Irritability is often described as a common problem affecting youth referred for mental health services; however, little is known about the prevalence and nature of irritability as a focus of treatment. We examined assessment data from a diverse sample of youths (N = 206; ages 7-15; 52% male, 48% female; 33% White, 27% Black, 25% Latinx) referred for outpatient treatment of emotional and behavioral concerns. Caregivers and youths completed nomothetic (standardized checklist) and idiographic (free response) measures at intake. Irritability was identified as a top problem (TP) in 58% of cases, commonly reported by caregivers (38%), youths (42%), or both (23%)-rates that were significantly greater than those of other TP domains (depression, anxiety, ADHD, conduct, and defiance). Further analyses identified clinical correlates of irritability TPs, with results supporting the incremental utility of multiple informants and methods. Findings suggest that irritability is among the most common problems for which families seek youth treatment.

Irritability in developmental age: A narrative review of a dimension crossing paediatric psychopathology

OBJECTIVE

Irritability is an important theme in paediatric psychiatry considering its high frequency in developmental age, its association with negative outcomes and consequently significant public health impact. Present as main or associated feature of several psychiatric diagnoses, irritability represents a challenge for clinicians who try to understand its origin and role in developmental psychopathology. In this review we try to: (1) get an overview of this dimension and its relationship with each of the main neuropsychiatric disorders in paediatric population and (2) provide a summary of currently available instruments to assess irritability in children and adolescents.

METHOD

In this narrative review, an overview of irritability in children and adolescents is proposed focusing on selected literature.

RESULTS

Irritability as feature of many paediatric psychiatric conditions has been evaluated by many authors and included in classifications of paediatric psychiatric diseases. Framework of irritability evolved over time and dimension of irritability has been investigated using different tools and methodologies, both qualitative and quantitative. Metrics of irritability as clinical dimension are important in the diagnostic process of paediatric diseases.

CONCLUSION

Investigating the presence of irritability in all children with related disorders is mandatory if we consider the risk for functional impairment and affective and behavioural disorders associated with high levels of irritability. Using rigid threshold in developmental age to differentiate physiological from pathological irritability could lead many children having subthreshold levels of irritability to receive no diagnosis and, consequently, no treatment where instead a dimensional approach to irritability could allow to identify prodromal phase and prevent the evolution towards clinical pathological expressions.

Novel insights into irritability: the relationship between subjective experience, age and mood

BACKGROUND

The relationship between irritability as a subjective experience and the behavioural indicators typically used to measure the construct are not known. Its links to mood, and contextual relationships, vary with age and are yet to be thoroughly examined.

AIMS

First, to interrogate the relationship between the subjective experience of irritability and mood, and that with its behavioural indicators. Second, to determine how these relationships vary with age and over time.

METHOD

This study examined data from a previous clinical trial of adolescents and young adults (N = 82) with bipolar disorder, who received a psychological intervention over 18 months. Participants completed a battery of questionnaires, which included assessments of irritability. Analyses of covariance were conducted to examine the interaction between mood symptoms, subjective measures of irritability, behavioural measures of irritability and age over time.

RESULTS

Subjective irritability scores differed significantly over time when controlling for manic, but not depressive, symptom scores. Further, subjective irritability significantly differed when controlling for behavioural measures of irritability (temper outbursts and argumentativeness). There were significant interactions between scores of depressive symptoms, temper outbursts and subjective irritability with age, wherein younger participants showed no correlation between depressive symptoms and temper outbursts. In addition, younger participants showed lower correlations between subjective irritability and both depressive and temper outburst scores, than older participants.

CONCLUSIONS

Subjective irritability is linked to mood morbidity and behavioural outbursts, and these relationships are contingent on age. Our novel findings suggest that subjective irritability should be assessed in greater detail in patients with mood disorders.

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.

Preventing Irritability and Temper Outbursts in Youth by Building Resilience

Severe irritability and temper outbursts are risk factors for the onset of serious and lifelong mood disorders. In treating children and adolescents with severe irritability, clinicians should evaluate and address safety issues before acute stabilization of symptoms. Then, clinicians can initiate interventions to prevent the onset or relapses of the undesired behavior and its functional consequences. This review summarizes primary, secondary, and tertiary relapse prevention strategies, with an emphasis on strategies that build resilience in youth that mitigate the onset, recurrence, and progression of emotion dysregulation.

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

OBJECTIVE

Disruptive mood dysregulation disorder (DMDD) in DSM, characterized by severe, chronic irritability, currently excludes children <6 years of age. However, capitalizing on a burgeoning developmental science base to differentiate clinically salient irritability in young children may enable earlier identification. The objective of this study was to advance an empirically derived framework for early childhood DMDD (EC-DMDD) by modeling and validating DMDD patterns in early childhood and generating clinically informative, optimized behaviors with thresholds.

METHOD

Data (N = 425) were from 3 longitudinal assessments of the MAPS Study, spanning preschool (means = 4.7 and 5.5 years) to early school age (mean = 6.8 years). The Multidimensional Assessment Profile of Disruptive Behavior (MAP-DB) Temper Loss scale captured irritability, the Family Life Impairment Scale (FLIS) assessed cross-domain impairment at the preschool time points and the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS) was used to assess clinical status at early school age. Latent transition analyses differentiated children with EC-DMDD from children with low, transient, or nonimpairing irritability.

RESULTS

Developmental patterning of irritability proved important for normal:abnormal differentiation. Of children, 27% had initially high irritability, but only two-thirds of these were persistently highly irritable. Thus, "false positives" based on a single screen would be substantial. Yet, "false negatives" are low, as <1% of children with baseline low irritability demonstrated later high irritability. Based on the sequential preschool-age time points, 6.7% of children were identified with EC-DMDD, characterized by persistent irritability with pervasive impairment, similar to prevalence at older ages. Specific behaviors included low frustration tolerance; dysregulated, developmentally unexpectable tantrums; and sustained irritable mood, all of which sensitively (0.85-0.96) and specifically (0.80-0.91) identified EC-DMDD. EC-DMDD predicted irritability-related syndromes (DMDD, oppositional defiant disorder) at early school age better than downward extension of DSM DMDD criteria to preschool age.

CONCLUSION

These findings provide empirical thresholds for preschool-age clinical identification of DMDD patterns. The results lay the foundation for validation of DMDD in early childhood and inform revision of DSM criteria.

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.

The Impact of Persistent Irritability on the Medication Treatment of Paediatric Attention Deficit Hyperactivity Disorder

This study compares the efficacy and tolerability of central nervous system (CNS) stimulants in children with attention deficit hyperactivity disorder (ADHD) with and without prominent irritability (IRR) over the course of 30 months. This is a secondary analysis of a study examining growth patterns in medication naïve children with ADHD subsequently treated with CNS stimulants (predominantly OROS-Methylphenidate, up to 54 mg per day) for 30 months. Participants had to meet full diagnostic criteria for ADHD and been treated with CNS stimulants for under 30 days. Children were classified as IRR if they were rated as pretty much or very much on either of the "often angry" or easily annoyed" items plus "lose temper," items of the Disruptive Behavior Disorders Rating Scale (DBDRS). Structured ratings of ADHD symptoms, impairment, side effects, and symptoms of oppositional defiant disorder (ODD) were collected every 2-12 weeks for the duration of the study. Medication use was measured by pill count and parent report. The IRR group comprised 28% of all participants. The IRR group had significantly higher levels of ADHD and ODD symptoms, impairment, and side effects ratings at baseline. In the IRR group, ODD symptoms, emotional lability, and impairment significantly decreased for participants with higher medication use. Total side effects increased for non-IRR participants with higher medication use. Emotional side effects decreased for IRR participants with higher medication use. Central nervous system stimulants were a tolerable and efficacious treatment in treatment naïve youth with ADHD with irritability. Clinical Trials Registration: NCT01109849.

Unpacking Associations between Mood Symptoms and Screen Time in Preadolescents: a Network Analysis

Mounting evidence highlights the link between screen time and adolescent mood problems. However, there are several shortcomings to the extant literature: (1) this link is underexplored in preadolescents, (2) most existing studies look at mood problems using categorical diagnoses rather than from a symptom-level perspective, despite the heterogeneity within mood disorders, (3) few studies have simultaneously examined the links of mood symptoms with different types of screen time, and (4) family/child-level factors that have shown links to youth psychopathology are not typically considered. This study, for the first time, examined the relationships of mood symptoms with different types of screen time, while accounting for theoretically important factors-parental monitoring and the behavioral inhibition/activation systems (BIS/BAS)-in preadolescents aged 9 to 10 from 9986 families participating in the Adolescent Brain and Cognitive Development Study. Using mixed graphical models, we found that screen time involving age-inappropriate content was stably and significantly associated with various elevated mood symptoms, independent from other types of screen time, BIS/BAS, and parental monitoring. Additionally, age-inappropriate screen time was associated with increased overall symptom connectivity. Further, preadolescents engaged in high levels of age-inappropriate screen time reported different symptom profiles (i.e., differences in symptom centralities) from common pediatric mood problems. Our findings underline the multifaceted role (i.e., direct associations with symptoms, a moderator for symptom relationships, associations with distinct symptom profiles) of age-inappropriate screen time in preadolescent mood problems. These findings serve as foundations for future research that may facilitate early detection of preadolescents at risk of mood problems.

Assessment of irritability in school-aged children by pediatric, family practice, and psychiatric providers

BACKGROUND

Irritability, a common behavioral problem for school-aged children, is often first assessed by primary care providers, who manage about a third of mental health conditions in children. Until recent changes in the Diagnostic and Statistical Manual of Mental Disorders (DSM), irritability was often associated with mood disorders, which may have led to increases in bipolar disorder diagnosis and prescription of mood stabilizing medication.

OBJECTIVE

Our aim was to explore differences between the approaches psychiatric and primary care providers use to assess irritability.

METHODS

A single trained interviewer conducted detailed interviews and collected demographic data from a homogeneous group of physicians that saturated with a sample size of 17 pediatric, family medicine, and psychiatric providers who evaluate and treat school-aged children. Qualitative and quantitative data were collected and analyzed.

RESULTS

In general, primary care providers chose to refer children with irritability to mental health specialists when medication management became complex, while the psychiatric providers chose behavior modification and parent education strategies rather than medications. The psychiatric group had a significantly higher caseload mix, prior experience with irritability, and more confidence in their assessment capabilities. There was lack of continuing medical education about irritability in all groups.

CONCLUSION

This preliminary study highlights the importance of collaboration between primary care and subspecialties to promote accurate assessment and subsequent treatment of school-aged children with irritability, who can represent a safety concern for self and others. More research is needed to establish an efficient method of assessing and managing irritability in primary care and better utilization of specialists.

The Clinician Affective Reactivity Index: Validity and Reliability of a Clinician-Rated Assessment of Irritability

Irritability is impairing in youth and is the core feature of disruptive mood dysregulation disorder (DMDD). Currently, there are no established clinician-rated instruments to assess irritability in pediatric research and clinical settings. Clinician-rated measures ensure consistency of assessment across patients and are important specifically for treatment research. Here, we present data on the psychometric properties of the Clinician Affective Reactivity Index (CL-ARI), the first semistructured interview focused on pediatric irritability. The CL-ARI was administered to a transdiagnostic sample of 98 youth (M age = 12.66, SD = 2.47; 41% female). With respect to convergent validity, CL-ARI scores were (a) significantly higher for youth with DMDD than for any other diagnostic group, and (b) showed uniquely strong associations with other clinician-, parent-, and youth-report measures of irritability compared to measures of related constructs, such as anxiety. The three subscales of the CL-ARI (temper outbursts, irritable mood, impairment) showed excellent internal consistency. Test-retest reliability of the CL-ARI was adequate. These data support that irritability can be feasibly, validly, and reliably assessed by clinicians using the CL-ARI. A validated, gold-standard assessment of pediatric irritability is critical in advancing research and treatment efforts.

Irritability as a Transdiagnostic Vulnerability Trait:Current Issues and Future Directions

In recent years, irritability has received increasing attention among mental health professionals given its transdiagnostic associations with diverse forms of psychopathology. In contrast to other emotional states and traits, however, literature addressing associations between irritability and related temperament and personality constructs is limited. In addition, those who study irritability have diverse perspectives on its neurobiological substrates. In this comment, we situate irritability in the literatures on child temperament and adult personality, and describe a model in which irritability derives from low tonic dopamine (DA) levels and low phasic DA reactivity in subcortical neural structures implicated in appetitive responding. We note that different findings often emerge in neuroimaging studies when irritability is assessed in circumscribed diagnostic groups versus representative samples. We conclude with directions for future research, and propose that more authors use hierarchical Bayesian modeling, which captures functional dependencies between irritability and other dispositional traits (e.g., trait anxiety) that standard regression models are insensitive too. Treatment implications are also considered.

Heritability, stability, and prevalence of tonic and phasic irritability as indicators of disruptive mood dysregulation disorder

BACKGROUND

Little is known about genetic and environmental influences on the components of disruptive mood dysregulation disorder (DMDD), tonic irritability (i.e., irritable mood) and phasic irritability (i.e., temper outbursts). This study examined prevalence, stability, and heritability of tonic irritability, phasic irritability, and a DMDD proxy (pDMDD) based on DSM-5 criteria.

METHODS

pDMDD was derived using data from clinical interviews of parents and their twins (N = 1,431 twin pairs), ages 8-17, participating in Waves 1 and 2 of the Virginia Twin Study of Adolescent Behavioral Development. Biometrical modeling was used to compare a common pathway model (CPM) and an independent pathway model (IPM), and heritability estimates were obtained for pDMDD using the symptoms of irritable mood (tonic irritability; DMDD Criterion D), intense temper outbursts (phasic irritability; DMDD Criterion A), and frequent temper outbursts (phasic irritability; DMDD Criterion C).

RESULTS

Lifetime prevalence of pDMDD was 7.46%. The stability of DMDD symptoms and the pDMDD phenotype across approximately one year were moderate (.30-.69). A CPM was a better fit to the data than an IPM. Phasic irritability loaded strongly onto the pDMDD latent factor (.89-.96) whereas tonic irritability did not (.28). Genetic influences accounted for approximately 59% of the variance in the latent pDMDD phenotype, with the remaining 41% of the variance due to unique environmental effects. The heritability of tonic irritability (54%) was slightly lower than that of frequent and intense temper (components of phasic irritability; 61% and 63%, respectively).

CONCLUSIONS

Compared to tonic irritability, phasic irritability appears to be slightly more stable and heritable, as well as a stronger indicator of the latent factor. Furthermore, environmental experiences appear to play a substantial role in the development of irritability and DMDD, and researchers should seek to elucidate these mechanisms in future work.

Examining ODD/ADHD Symptom Dimensions as Predictors of Social, Emotional, and Academic Trajectories in Middle Childhood

The goal of this article is to investigate the symptom dimensions of oppositional defiant disorder (ODD; irritability, defiance) and attention deficit/hyperactivity disorder (ADHD; inattention, hyperactivity-impulsivity) as predictors of academic performance, depressive symptoms, and peer functioning in middle childhood. Children (N = 346; 51% female) were assessed via teacher-report on measures of ODD/ADHD symptoms at baseline (Grades K-2) and academic performance, depressive symptoms, peer rejection, and victimization on 7 occasions over 4 school years (K-2 through 3-5). Self-report and grade point average data collected in Grades 3-5 served as converging outcome measures. Latent growth curve and multiple regression models were estimated using a hierarchical/sensitivity approach to assess robustness and specificity of effects. Irritability predicted higher baseline depressive symptoms, peer rejection, and victimization, whereas defiance predicted higher baseline peer rejection; however, none of these ODD-related effects persisted 3 years later to Grades 3-5. In contrast, inattention predicted persistently poorer academic performance, persistently higher depressive symptoms, and higher baseline victimization; hyperactivity-impulsivity predicted subsequent peer rejection and victimization in Grades 3-5. In converging models, only inattention emerged as a robust predictor of 3-year outcomes (viz., grade point average, depressive symptoms, peer rejection, and relational victimization). Broadly, ODD dimensions-particularly irritability-may be linked to acute disturbances in social-emotional functioning in school-age children, whereas ADHD dimensions may predict more persistent patterns of peer, affective, and academic problems. By examining all 4 ODD/ADHD symptom dimensions simultaneously, the present analyses offer clarity and specificity regarding which dimensions affect what outcomes, and when. Findings underscore the importance of multidimensional approaches to research, assessment, and intervention.

Practitioner Review: Definition, recognition, and treatment challenges of irritability in young people

BACKGROUND

Irritability is one of the most common reasons for referral to child and adolescent mental health services and is the main characteristic of the new diagnosis of disruptive mood dysregulation disorder (DMDD). However, the recognition and management of irritability presents a major challenge in clinical practice and may be partly responsible for the dramatic increase in antipsychotic prescribing in recent years.

METHODS

In this review, we provide up-to-date information on the definition and mechanisms underlying irritability, and its assessment in clinical practice. We aim to discuss the latest research on DMDD, and the presence of severe irritability in the context of other disorders, as well as to recommend a treatment algorithm.

RESULTS

Severe irritability is associated with aberrant reward processing and bias toward threatening stimuli. Several measures are available to easily assess irritability. The recent diagnosis of DMDD captures children whose main problem is severe irritability and differ from those with bipolar disorder in longitudinal outcomes, family history, and behavioral and neural correlates. Treatment of irritability might depend on the context it appears. Indirect evidence suggests that parent management training (PMT) and cognitive behavioral therapy (CBT) are the most supported psychological treatments for irritability.

CONCLUSIONS

Irritability, recognized as a mood problem rather than a purely behavioral manifestation, is a common condition for young people. Practitioners should not ignore irritability as it is associated with substantial morbidity and impairment. Although there are no trials with irritability as main outcome, clinicians can apply several existing pharmacological and psychological interventions for its treatment. Also, new promising approaches relying on pathophysiological findings, such as exposure-based cognitive behavioral therapy techniques and interpretation bias training (IBT), are being currently investigated.

The Neurodevelopmental Basis of Early Childhood Disruptive Behavior: Irritable and Callous Phenotypes as Exemplars

The arrival of the Journal's 175th anniversary occurs at a time of recent advances in research, providing an ideal opportunity to present a neurodevelopmental roadmap for understanding, preventing, and treating psychiatric disorders. Such a roadmap is particularly relevant for early-childhood-onset neurodevelopmental conditions, which emerge when experience-dependent neuroplasticity is at its peak. Employing a novel developmental specification approach, this review places recent neurodevelopmental research on early childhood disruptive behavior within the historical context of the Journal. The authors highlight irritability and callous behavior as two core exemplars of early disruptive behavior. Both phenotypes can be reliably differentiated from normative variation as early as the first years of life. Both link to discrete pathophysiology: irritability with disruptions in prefrontal regulation of emotion, and callous behavior with abnormal fear processing. Each phenotype also possesses clinical and predictive utility. Based on a nomologic net of evidence, the authors conclude that early disruptive behavior is neurodevelopmental in nature and should be reclassified as an early-childhood-onset neurodevelopmental condition in DSM-5. Rapid translation from neurodevelopmental discovery to clinical application has transformative potential for psychiatric approaches of the millennium. [AJP at 175: Remembering Our Past As We Envision Our Future November 1938: Electroencephalographic Analyses of Behavior Problem Children Herbert Jasper and colleagues found that brain abnormalities revealed by EEG are a potential causal factor in childhood behavioral disorders. (Am J Psychiatry 1938; 95:641-658 )].

Prevalence Rate and Course of Symptoms of Disruptive Mood Dysregulation Disorder (DMDD)

Abstract. Objective: According to DSM-5, Disruptive Mood Dysregulation Disorder (DMDD) is characterized by chronic temper outbursts and irritable moods. So far, little is known about its prevalence rate, course and influence on individual well-being. We assessed the prevalence rates of DMDD symptoms during adulthood and primary school age – the latter retrospectively – and studied their relationship with psychiatric disorders and socioeconomic variables. Methods: A total of 2,413 subjects, aged 18–94 years, participated in this population-based, representative study based on self-reports. Results: 12 (0.50 %) subjects reported elevated DMDD symptoms during adulthood, and 19 (0.79 %) reported elevated DMDD symptoms during primary school age. DMDD symptoms were associated with higher rates of depression and anxiety symptoms. Those reporting elevated DMDD symptoms during adulthood were more often single or divorced, and those reporting elevated DMDD symptoms during primary school age were more often childless and unemployed during adulthood compared to subjects without DMDD symptoms. Conclusions: DMDD symptoms seem to show a chronic course and go hand in hand with elevated psychiatric symptoms and impaired socioeconomic and demographic status.

ODD Symptom Network during Preschool

Several different conceptualizations of Oppositional Defiant Disorder (ODD) symptoms have been proposed, including one undivided set of symptoms (DSM-IV-TR; APA 2000); two domains of symptoms subdivided into affective and behavioral; and three domains of symptoms subdivided as angry/irritable, argumentative/defiant, and spiteful. The current study utilizes a novel approach to examining the division of ODD symptoms through use of network analysis. Participants were 109 preschoolers (64 male) between the ages of three and six (M = 4.34 years, SD = 1.08) and their parents and teachers/caregivers, who provided ratings of ODD symptoms. Results are consistent with one-, two-, and three- cluster solutions of ODD, but perhaps provide most support for the three-cluster solution. In addition, results support the idea that negative affect, particularly anger, forms the core of the ODD symptom network during preschool. These results suggest the importance of targeting anger in preschool interventions for ODD.

The association between Disruptive Mood Dysregulation Disorder symptoms and sleep problems in children with and without ADHD

BACKGROUND

Many youth experience persistent irritability and recurrent temper outbursts, conceptualized by DSM-5 as Disruptive Mood Dysregulation Disorder (DMDD). Sleep deprivation impairs emotion regulation which could increase rates of DMDD symptoms, especially in those with preexisting regulatory impairments, as seen with ADHD. However, there has been little examination of the relationship between chronic sleep problems and DMDD symptoms.

METHODS

Associations between DMDD symptoms and sleep parameters in children were assessed using parent-report and objective measures of sleep in a general population sample (N = 665) and an ADHD sample (N = 784). Irritability, temper outbursts, sleep problems and other psychological problems were assessed with the Pediatric Behavior Scale. The general population study also completed overnight polysomnography (PSG).

RESULTS

DMDD symptoms were reported in 9.2% of the community sample and 31.4% of the ADHD sample. In both samples, children with DMDD symptoms had significantly higher parent-reported sleep problems than children without DMDD symptoms. Children with sleep problems had significantly higher DMDD scores than children without sleep problems. However, DMDD symptoms were most strongly associated with oppositional behavior. Sleep problems were not a significant contributor. Hyperactivity-impulsivity was most strongly associated with sleep problems, and DMDD was not a significant contributor. Children with and without DMDD symptoms did not differ significantly on any PSG parameter.

CONCLUSIONS

Associations between parent-reported sleep problems and DMDD symptoms were due to their shared relationship with other behavioral problems. Therefore, chronic sleep problems do not appear to be a primary source of DMDD symptoms in children with or without ADHD.

Irritability in child and adolescent psychopathology: An integrative review for ICD-11

In preparation for the World Health Organization's development of the Eleventh Revision of the International Classification of Diseases and Related Health Problems (ICD-11) chapter on Mental and Behavioral Disorders, this article reviews the literature pertaining to severe irritability in child and adolescent psychopathology. First, research on severe mood dysregulation suggests that youth with irritability and temper outbursts, among other features of hyperactivity and arousal, demonstrate cross-sectional correlates and developmental outcomes that distinguish them from youth with bipolar disorder. Second, other evidence points to an irritable dimension of Oppositional Defiant Disorder symptomatology, which is uniquely associated with concurrent and subsequent internalizing problems. In contrast to the Diagnostic and Statistical Manual of Mental Disorders' (5th ed.) Disruptive Mood Dysregulation Disorder, our review of the literature supports a different solution: a subtype, Oppositional Defiant Disorder with chronic irritability/anger (proposal included in Appendix). This solution is more consistent with the available evidence and is a better fit with global public health considerations such as harm/benefit potential, clinical utility, and cross-cultural applicability. Implications for assessment, treatment, and research are discussed.

[The Severe Chronic Irritability Concept: A clinical dimension to consider in child and adolescent]

INTRODUCTION

For a decade, the concept of irritability has known a renewed interest in infant and child psychopathology. Indeed, longitudinal follow-up studies clearly highlighted their predictive value - in the short, medium and long terms - of a broad field of behavioral disorders and emotion dysregulation. This dimensional and transnosographic approach of irritability, coupled with the latest neuroscience data, points out that irritability could be the equivalent of a psychopathological marker, covering both a neurobiological, cognitive and emotional component. It is a major challenge today to better understand the developmental sequence of severe chronic irritability and its predictive influence on the etiology of mental disorders from childhood to adulthood.

METHOD

We briefly review here the latest current data on this topic.

RESULTS

The important point is that chronic and non-episodic irritability in children, associated with strong emotional sensitivity to negative events and frequent access of anger, could have a predictive value for progression to anxiety disorder or severe mood disorder but not to bipolar disorder as it was believed until now. The risk of developing a bipolar disorder would be more frequently correlated with the notion of transient and episodic irritability in a context of previous family history of bipolar disorder.

CONCLUSION

Further studies are expected to narrow the discriminative validity of this notion of severe irritability and confirm or not its relevance as a major clinical criterion of Severe Mood Disorders in children and adolescents introduced in the last version of DSM (DSM-5).

Pediatric Bipolar Disorder

The diagnosis of bipolar disorder (BD) in youth is confusing and controversial. Controversy notwithstanding, youth diagnosed with BD have high behavioral health needs and are at elevated risk for problematic long-term psychosocial functioning and complex psychiatric medication regimens. Pediatricians and other primary care providers (PCPs) can play an important role in the assessment and treatment of youth diagnosed with BD and the recently created and also controversial diagnosis of disruptive mood dysregulation disorder (DMDD). This article provides information on the definitions, background, and presentation of pediatric bipolar disorder (PBD), how to differentiate PBD from other psychiatric disorders, effective psychiatric and psychosocial interventions for PBD, potential roles for PCPs, and what is known about DMDD. [Pediatr Ann. 2016;45(10):e362-e366.].

Cognitive-Behavioral Therapy for a 9-Year-Old Girl With Disruptive Mood Dysregulation Disorder

Disruptive mood dysregulation disorder (DMDD) is a relatively new diagnosis in the field of childhood onset disorders. Characterized by both behavior and mood disruption, DMDD is a purportedly unique clinical presentation with few relevant treatment studies to date. The current case study presents the application of cognitive-behavioral therapy (CBT) for anger and aggression in a 9-year-old girl with DMDD, co-occurring attention deficit hyperactivity disorder (ADHD), and a history of unspecified anxiety disorder. At the time of intake evaluation, she demonstrated three to four temper outbursts and two to three episodes of aggressive behavior per week, in addition to prolonged displays of non-episodic irritability lasting hours or days at a time. A total of 12 CBT sessions were conducted over 12 weeks and 5 follow-up booster sessions were completed over a subsequent 3-month period. Irritability-related material was specially designed to target the DMDD clinical presentation. Post-treatment and 3-month follow-up assessments, including independent evaluation, demonstrated significant decreases in the target symptoms of anger, aggression, and irritability. Although the complexities of diagnosing and treating DMDD warrant extensive research inquiry, the current case study suggests CBT for anger and aggression as a viable treatment for affected youth.

The Status of Irritability in Psychiatry: A Conceptual and Quantitative Review

OBJECTIVE

Research and clinical interest in irritability have been on the rise in recent years. Yet several questions remain about the status of irritability in psychiatry, including whether irritability can be differentiated from other symptoms, whether it forms a distinct disorder, and whether it is a meaningful predictor of clinical outcomes. In this article, we try to answer these questions by reviewing the evidence on how reliably irritability can be measured and its validity.

METHOD

We combine a narrative and systematic review and meta-analysis of studies. For the systematic review and meta-analysis, we searched studies in PubMed and Web of Science based on preselected criteria. A total of 163 articles were reviewed, and 24 were included.

RESULTS

We found that irritability forms a distinct dimension with substantial stability across time, and that it is specifically associated with depression and anxiety in longitudinal studies. Evidence from genetic studies reveals that irritability is moderately heritable, and its overlap with depression is explained mainly by genetic factors. Behavioral and neuroimaging studies show that youth with persistent irritability exhibit altered activations in the amygdala, striatum, and frontal regions compared with age-matched healthy volunteers. Most knowledge about the treatment of irritability is based on effects of treatment on related conditions or post hoc analyses of trial data.

CONCLUSION

We identify a number of research priorities including innovative experimental designs and priorities for treatment studies, and conclude with recommendations for the assessment of irritability for researchers and clinicians.

Irritability in Pediatric Patients: Normal or Not?

The goal of this article is to describe the concept of irritability in children and youth, which has been revisited in the DSM-5. Traditionally, this behavior has been more commonly associated with mood disorders, which may account for the rising incidence of bipolar disorder diagnosis and overuse of mood-stabilizing medications in pediatric patients. While not predictive of mania, persistent nonepisodic irritability, if undetected, may escalate to violent behavior with potentially serious outcomes. It is therefore important to educate clinicians about how to accurately assess irritability in pediatric patients.

Disruptive Mood Dysregulation Disorder Symptoms and Association with Oppositional Defiant and Other Disorders in a General Population Child Sample

OBJECTIVE

The new Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (DSM-5) diagnosis, disruptive mood dysregulation disorder (DMDD), has generated appreciable controversy since its inception, primarily in regard to its validity as a distinct disorder from oppositional defiant disorder (ODD). The goal of our study was to determine if the two DSM-5 DMDD symptoms (persistently irritable or angry mood and severe recurrent temper outbursts) occurred independently of other disorders, particularly ODD. Other DSM-5 DMDD criteria were not assessed.

METHODS

Maternal ratings of the two DMDD symptoms, clinical diagnosis of ODD using DSM-5 symptom criteria, and psychological problem scores (anxiety, depression, oppositional behavior, conduct disorder, and attention-deficit/hyperactivity disorder [ADHD]) on the Pediatric Behavior Scale were analyzed in a population sample, 6-12 years of age (n = 665).

RESULTS

The prevalence of DMDD symptoms (irritable-angry mood and temper outbursts both rated by mothers as often or very often a problem) was 9%. In all, 92% of children with DMDD symptoms had ODD, and 66% of children with ODD had DMDD symptoms, indicating that it is very unlikely to have DMDD symptoms without ODD, but that ODD can occur without DMDD symptoms. Comorbid psychological problems (anxiety, depression, conduct disorder, and ADHD) in addition to ODD did not increase the risk of having DMDD symptoms beyond that for ODD alone. Only 3% of children with psychological problems other than ODD had DMDD symptoms.

CONCLUSIONS

Our general population findings are similar to those for a psychiatric sample, suggesting that DMDD cannot be differentiated from ODD based on symptomatology. Therefore, it is important to assess all DSM criteria and to examine for comorbid psychopathology when considering a diagnosis of DMDD. Our results support the recommendation made by the World Health Organization's International Classification of Diseases, 11th Revision (ICD-11) panel of experts that DMDD symptoms may be more appropriately classified as an ODD specifier than a separate diagnosis.

A Randomized Clinical Trial of an Integrative Group Therapy for Children With Severe Mood Dysregulation

OBJECTIVE

Nonepisodic irritability is a common and impairing problem, leading to the development of the diagnoses severe mood dysregulation (SMD) and disruptive mood dysregulation disorder (DMDD). No psychosocial therapies have been formally evaluated for either, with medication being the most common treatment. This study examined the feasibility and efficacy of a joint parent-child intervention for SMD.

METHOD

A total of 68 participants aged 7 to 12 years with attention-deficit/hyperactivity disorder (ADHD) and SMD were randomly assigned to the 11-week therapy or community-based psychosocial treatment. All participants were first stabilized on psychostimulant medication by study physicians. Of the participants, 56 still manifested impairing SMD symptoms and entered the therapy phase. Masked evaluators assessed participants at baseline, midpoint, and endpoint, with therapy participants reassessed 6 weeks later.

RESULTS

All but 2 therapy participants attended the majority of sessions (n = 29), with families reporting high levels of satisfaction. The primary outcome of change in mood symptoms using the Mood Severity Index (MSI) did not reach significance except in the subset attending the majority of sessions (effect size = 0.53). Therapy was associated with significantly greater improvement in parent-rated irritability (effect size = 0.63). Treatment effects for irritability but not MSI diminished after therapy stopped. Little impact on ADHD symptoms was seen. Results may not be generalizable to youth with SMD and comorbidities different from those seen in this sample of children with ADHD, and are limited by the lack of a gold standard for measuring change in SMD symptoms.

CONCLUSION

While failing to significantly improve mood symptoms versus community treatment, the integrative therapy was found to be a feasible and efficacious treatment for irritability in participants with SMD and ADHD.

CLINICAL TRIAL REGISTRATION INFORMATION

Group-Based Behavioral Therapy Combined With Stimulant Medication for Treating Children With Attention Deficit Hyperactivity Disorder and Impaired Mood; http://clinicaltrials.gov/; NCT00632619.

Disruptive Mood Dysregulation Disorder Among Children and Adolescents

Disruptive mood dysregulation disorder (DMDD) was introduced in the mood disorders section of DSM-5. Its primary symptoms are "severe, recurrent temper outbursts" (manifested verbally and/or physically) superimposed on and associated with chronic irritability. DMDD is a condition with an early age of onset (i.e., symptoms apparent by age 10, although the diagnosis cannot be made before age 6); however, nothing is known about the condition among adults in part because questions about temper outbursts (versus "often losing temper") are not consistently asked after 6 years of age. Other qualifiers are present so that better-known conditions are not overlooked. For instance, manic symptoms that are present for more than 1 day, symptoms that are not exclusively occurring during major depressive disorder, or symptoms that are better explained by autism, posttraumatic stress disorder, separation anxiety, and dysthymia are exclusionary. Although DMDD can co-occur with attention-deficit hyperactivity disorder (ADHD), conduct disorder, and substance use disorder, it preempts diagnoses of both oppositional defiant disorder and intermittent explosive disorder.

Disruptive mood dysregulation disorder: current insights

Disruptive mood dysregulation disorder (DMDD) was introduced as a new diagnostic entity under the category of depressive disorders in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). It was included in DSM-5 primarily to address concerns about the misdiagnosis and consequent overtreatment of bipolar disorder in children and adolescents. DMDD does provide a home for a large percentage of referred children with severe persistent irritability that did not fit well into any DSM, Fourth Edition (DSM-IV) diagnostic category. However, it has been a controversial addition to the DSM-5 due to lack of published validity studies, leading to questions about its validity as a distinct disorder. In this article, the authors discuss the diagnostic criteria, assessment, epidemiology, criticism of the diagnosis, and pathophysiology, as well as treatment and future directions for DMDD. They also review the literature on severe mood dysregulation, as described by the National Institute of Mental Health, as the scientific support for DMDD is based primarily on studies of severe mood dysregulation.