Identifying Novel Types of Irritability Using a Developmental Genetic Approach

Is irritability multidimensional: Psychometrics of The Irritability and Dysregulation of Emotion Scale (TIDES-13)

Irritability is a common, impairing, and potentially multifaceted manifestation of psychopathology. We designed The Irritability and Dysregulation of Emotion Scale (TIDES-13) to determine whether various expressions of irritability in children and youth form multiple subdimensions with distinct correlates. We administered parent-report (n = 3875, mean age = 8.9) and youth self-report (n = 579, mean age = 15.1) versions of TIDES-13 in a population and community-based sample. We conducted exploratory/confirmatory factor analyses and regression analyses to examine the dimensionality of TIDES-13 and the associations of the scale with age, gender, anxiety, depression, ODD, ADHD traits, and the Affective Reactivity Index (ARI). A higher-order model with a global irritability dimension and four subdimensions, including proneness to anger (PA), internalized negative emotional reactivity (iNER), externalized negative emotional reactivity (eNER), and reactive aggression (RA), showed good to excellent fit in both parent-report and self-report. The global irritability dimension showed excellent internal reliability (⍵Total; parent-report = 0.97, ⍵Total; self-report = 0.95), explained a majority of the item variance (⍵Hierarchical; parent-report = 0.94, ⍵Hierarchical; self-report = 0.90), and was moderately correlated with the ARI (rparent = 0.68, rself = 0.77). Subdimensions PA, eNER, and RA were negatively associated with age in males, whereas iNER was positively associated with age in females. Traits of ODD and ADHD were associated primarily with the global irritability dimension, whereas iNER was strongly associated with anxiety and depression traits over and above the global irritability dimension. Our results support a unidimensional interpretation of irritability in a population sample. However, limited evidence of specific behavioral, age, and sex correlates with particular irritability subdimensions may warrant further investigation.

Irritability: associations with real-time affect dynamics, social interactions, and daily substance use in older adolescents

Irritability is a common and clinically significant symptom associated with a wide range of negative outcomes. Ecological Momentary Assessment (EMA) is a valuable tool for capturing experiences, such as emotions, social interactions, and substance use in real-time, and may be useful in understanding how irritability is related to everyday functioning. We investigated cross-sectional associations between a widely used self-report irritability rating scale and affect dynamics, social interactions, and substance use captured with EMA (5 surveys daily for 14 days) in 349 18-year-olds. We also examined the associations of self- and parent-reported irritability at ages 12 and 15 with the age 18 EMA variables to explore whether these relationships persist over time. Youth-reported irritability at age 18 was linked to greater intensity, variability, and inertia of irritability, sadness, and anxiety, less positive and more negative interpersonal experiences, and greater cigarette and drug use. Most effect sizes were in the medium-small range. Associations of youth- and parent-reported irritability at ages 12 and 15 with the age 18 EMA measures were generally similar, although smaller in magnitude. Findings contribute to understanding how irritability is manifested in real-time affect dynamics and interpersonal functioning, as well as daily substance use. Most effects were evident over the course of up to 6 years - that is, early adolescent irritability, reported by both youth and their parents, was associated with similar real-time affect dynamics and interpersonal experiences at age 18. This study contributes to the literature on the developmental psychopathology of irritability by extending findings to everyday functioning.

Early Predictors and Concurrent Correlates of Tonic and Phasic Irritability in Adolescence

Irritability is a common presenting problem in youth mental health settings that is thought to include two components: tonic (e.g., irritable, touchy mood) and phasic (e.g., temper outbursts), each with unique correlates and outcomes, including later internalizing and externalizing problems, respectively. However, we are unaware of any studies of early predictors of tonic and phasic irritability. We utilized data from a longitudinal study of a community sample of 3-year-old children followed to age 15 (n = 444). We conducted confirmatory factor analysis (CFA) of items from several self-report irritability measures at age 15, including the Affective Reactivity Index, the International Personality Item Pool, the Schedule for Non-Adaptive and Adaptive Personality Youth Version, and the Child Depression Inventory, and examined their early childhood predictors. The CFA identified dimensions consistent with tonic and phasic irritability. Tonic irritability at age 15 was uniquely associated with concurrent internalizing disorders and suicidal behavior while phasic irritability was uniquely associated with concurrent externalizing disorders. When adolescent tonic and phasic irritability were examined together, female sex and parental depressive and substance use disorders at age 3 uniquely predicted adolescent tonic irritability. Additionally, male sex, less parental education, greater laboratory-observed anger and impulsivity, ODD symptoms, higher irritability, and no parental substance use history at age 3 uniquely predicted adolescent phasic irritability. Youth-reported tonic and phasic irritability at age 15 appear to be distinguishable constructs with distinct concurrent correlates and early antecedents. Findings have important implications for research on the etiology of irritability and developing effective treatments.

Psychometric Evaluation of the Affective Reactivity Index Among Children and Adolescents in China: A Multi-Method Assessment Approach

The Affective Reactivity Index (ARI) is one of the most studied scales for assessing youth irritability, but little is known about its measurement performance in community populations. This study applied item response theory (IRT), network analysis, and classical test theory (CTT) to examine the psychometric properties of the ARI in a sample of n = 395 community-based children (Mage = 13.44, SD = 2.51) and n = 403 parents. In this sample, the ARI demonstrated good reliability, as well as convergent and concurrent validity. The one-factor structure was supported by both confirmatory factor analysis (CFA) and network analysis. IRT analysis revealed that the ARI effectively distinguished between various levels of irritability within the community population. Network analysis identified "Loses temper easily,""Gets angry frequently," and "Often loses temper" are central aspects of irritability. The findings support the ARI as a brief, reliable, and valid instrument to assess irritability in community children and adolescents.

Irritability in young people with copy number variants associated with neurodevelopmental disorders (ND-CNVs)

A range of rare mutations involving micro-deletion or -duplication of genetic material (copy number variants (CNVs)) have been associated with high neurodevelopmental and psychiatric risk (ND-CNVs). Irritability is frequently observed in childhood neurodevelopmental conditions, yet its aetiology is largely unknown. Genetic variation may play a role, but there is a sparsity of studies investigating the presentation of irritability in young people with ND-CNVs. This study aimed to investigate whether there is a difference in irritability in young people with rare ND-CNVs compared to those without ND-CNVs, and to what extent irritability is associated with psychiatric diagnoses and cognitive ability (IQ). Irritability and broader psychopathology were assessed in 485 young people with ND-CNVs and 164 sibling controls, using the child and adolescent psychiatric assessment. Autism was assessed using the social communication questionnaire, and intelligence quotient (IQ) by the Wechsler abbreviated scale of intelligence. Fifty four percent of young people with ND-CNVs met the threshold for irritability; significantly more than controls (OR = 3.77, CI = 3.07-7.90, p = 5.31 × 10-11). When controlling for the presence of other psychiatric comorbidities, ND-CNV status was still associated with irritability. There was no evidence for a relationship between irritability and IQ. Irritability is an important aspect of the clinical picture in young people with ND-CNVs. This work shows that genetic variation is associated with irritability in young people with ND-CNVs, independent of psychiatric comorbidities or IQ impairment. Clinicians should be aware of this increased risk to inform management and interventions.

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

BACKGROUND

Irritability, marked by diminished frustration tolerance, holds significant implications for youth mental health treatment. Despite prior research on irritability trajectories, understanding of individual differences during adolescence remains limited. This study examines the stability and trajectory of irritability across ages 12-18, investigating associations with psychopathology and functioning at age 18.

METHODS

A community sample of families with 3-year-old children (N = 518) was recruited via commercial mailing lists. Irritability was assessed at ages 12, 15, and 18 using the Affective Reactivity Index. Psychopathology at age 18 was evaluated with the Kiddie Schedule for Affective Disorders and Schizophrenia, and functioning was assessed through the UCLA Life Stress Interview. Measurement invariance analyses and latent growth curve modeling were conducted within a structural equation modeling (SEM) framework.

RESULTS

Configural, metric, and scalar invariance models were supported. Elevated irritability at age 12 predicted adverse outcomes at age 18, including increased psychotropic medication use, mental health treatment, suicidal ideation, self-injury, and psychiatric disorders. Importantly, these associations persisted even after accounting for corresponding variables at age 12. The trajectory of irritability during early adolescence significantly predicted heightened risks for various outcomes at age 18, including suicidal ideation, depression, anxiety, disruptive behavior disorders, and impaired interpersonal functioning.

DISCUSSION

Limitations include using only youth-reported data at age 18, limited generalizability from a mostly White, middle-class sample, and insufficient exploration of the broader developmental trajectory of irritability. Nevertheless, the findings emphasize the crucial role of irritability's trajectory in influencing various psychopathological and functional outcomes in late adolescence.

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.

Modeling Shared and Specific Variances of Irritability, Inattention, and Hyperactivity Yields Novel Insights Into White Matter Perturbations

OBJECTIVE

Irritability, inattention, and hyperactivity, which are common presentations of childhood psychopathology, have been associated with perturbed white matter microstructure. However, similar tracts have been implicated across these phenotypes; such non-specificity could be rooted in their high co-occurrence. To address this problem, we use a bifactor approach parsing unique and shared components of irritability, inattention, and hyperactivity, which we then relate to white matter microstructure.

METHOD

We developed a bifactor model based on the Conners Comprehensive Behavioral Rating Scale in a sample of youth with no psychiatric diagnosis or a primary diagnosis of attention-deficit/hyperactivity disorder or disruptive mood dysregulation disorder (n = 521). We applied the model to an independent yet sociodemographically and clinically comparable sample (n = 152), in which we tested associations between latent variables and fractional anisotropy (FA).

RESULTS

The bifactor model fit well (comparative fit index = 0.99; root mean square error of approximation = 0.07). The shared factor was positively associated with an independent measure of impulsivity (ρS = 0.88, pFDR < .001) and negatively related to whole-brain FA (r = -0.20), as well as FA of the corticospinal tract (all pFWE < .05). FA increased with age and deviation from this curve, indicating that altered white matter maturation was associated with the hyperactivity-specific factor (r = -0.16, pFWE < .05). Inattention-specific and irritability-specific factors were not linked to FA.

CONCLUSION

Perturbed white matter microstructure may represent a shared neurobiological mechanism of irritability, inattention, and hyperactivity related to heightened impulsivity. Furthermore, hyperactivity might be uniquely associated with a delay in white matter maturation.

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.

Association Between Child Maltreatment and Aggression in Chinese Early Adolescents: The Mediating Role of Irritability

Child maltreatment (CM) is a major global public health issue, and a strong association exists between CM and aggression. However, the underlying mechanism of this association has not been understood to date. The objective of this study was to explore the mediating role of irritability in the association between CM and aggression in Chinese early adolescents. A cross-sectional study was conducted using a self-report questionnaire to evaluate the levels of CM, aggression, and irritability in 5,724 middle school students from the Anhui Province, China. Structural equation modeling was used to test the hypothesis of the mediating effect of irritability on the relationship between CM and aggression. We further investigated gender differences in this association using multiple group analyses. CM was positively related to both irritability and aggression, and irritability was positively associated with aggression (p < .01). The mediating effects of irritability between CM and aggression were significant (β = .107, 95% confidence intervals [CI]: 0.077-0.133, p < .05). Males had a higher indirect effect size of the pathway from CM to aggression via irritability compared with females. Overall, irritability was a crucial mediator in the relationship between CM and aggression in Chinese adolescents, and males were more prone to engage in aggression compared with females through the pathway of irritability. Therefore, early irritability characteristics should be carefully monitored in adolescents, and they should be provided adequate support to acquire critical emotion regulation skills.

Irritability in young people with copy number variants associated with neurodevelopmental disorders (ND-CNVs)

Background

A range of rare mutations involving micro-deletion or -duplication of genetic material (copy number variants (CNVs)) have been associated with high neurodevelopmental and psychiatric risk (ND-CNVs). Irritability is frequently observed in childhood neurodevelopmental conditions, yet its aetiology is largely unknown. Genetic variation may play a role, but there is a sparsity of studies investigating presentation of irritability in young people with ND-CNVs.

Aims

This study aimed to investigate whether there is a difference in irritability in young people with rare ND-CNVs compared to those without ND-CNVs, and to what extent irritability is associated with psychiatric diagnoses and cognitive ability (IQ).

Methods

Irritability and broader psychopathology was assessed in 485 young people with ND-CNVs and 164 sibling controls, using the child and adolescent psychiatric assessment (CAPA). Autism was assessed using the Social Communication Questionnaire (SCQ), and Intelligence Quotient (IQ) by the Wechsler Abbreviated Scale of Intelligence (WASI).

Results

54% of young people with ND-CNVs met the threshold for irritability; significantly more than controls (OR = 3.77, CI = 3.07-7.90, p= 5.31 × 10-11). When controlling for the presence of other psychiatric comorbidities, ND-CNV status was still associated with irritability. There was no evidence for a relationship between irritability and IQ.

Conclusions

Irritability is an important aspect of the clinical picture in young people with ND-CNVs. This work shows that genetic variation is associated with irritability in young people with ND-CNVs, independent of psychiatric comorbidities or IQ impairment. Clinicians should be aware of this increased risk to inform management and interventions.

The relationship between self-control and mental health problems among Chinese university students

Background

Mental health issues are often associated with poor self-control. Therefore, effective interventions against mental health problems should include self-control training. However, it is unclear whether the effect of self-control varies across different types of mental health problems.

Methods

A cross-sectional survey was conducted using the convenience sampling method at five universities in Chongqing, China, where 1,409 students reported their demographic information, level of self-control, and symptoms of irritability, depression, and anxiety. Descriptive statistical methods and a network analysis approach were employed to explore the relationship between self-control and symptoms of irritability, depression, and anxiety among 1,409 students. The bridging links between self-control and the three mental health problems were analyzed.

Results

The findings revealed a negative correlation between self-control and symptoms of irritability, depression, and anxiety among university students. Impulse control was found to be the bridge between self-control and irritability or anxiety symptoms, while resistance to temptation was the bridge between self-control and depressive symptoms.

Conclusion

These results demonstrate the different relationship between self-control with irritability, anxiety, and depressive symptoms. The findings of this study may shed light on future mental health interventions for university students during potential public health emergencies, such as prior knowledge of the main types of psychological problems among university students, which may allow for the development of precise self-control intervention strategies, such as targeting impulsivity or resistance to temptation.

Categorical and dimensional approaches to the developmental relationship between ADHD and irritability

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) and irritability commonly co-occur, and follow similar developmental trajectories from childhood to adolescence. Understanding of the developmental relationship between these co-occurrences is limited. This study provides a longitudinal assessment of how ADHD diagnostic status and symptom patterns predict change in irritability.

METHODS

A community sample of 337 participants (45.2% ADHD), recruited for the Childhood Attention Project, completed the Affective Reactivity Index (ARI) to measure irritability at baseline (mean age 10.5 years) and follow-up after 18-months. Latent change score models were used to assess how (a) baseline ADHD vs. control group status, (b) baseline symptom domain (inattention, hyperactivity-impulsivity) and (c) longitudinal change in ADHD symptom severity predicted change in irritability.

RESULTS

Irritability was significantly higher among the ADHD group than controls; however, change in irritability over time did not differ between groups. When assessed across the entire cohort, change in irritability was predicted by higher symptom count in the hyperactive-impulsive domain, but not the inattentive domain. Greater declines in ADHD symptoms over time significantly predicted greater declines in irritability. Baseline ADHD symptom severity was found to significantly predict change in irritability; however, baseline irritability did not significantly predict change in ADHD symptoms.

CONCLUSIONS

ADHD symptoms-particularly hyperactive-impulsive symptoms-predict the degree and trajectory of irritability during childhood and adolescence, even when symptoms are below diagnostic thresholds. The use of longitudinal, dimensional and symptom domain-specific measures provides additional insight into this relationship.

Offspring irritability: associations with parental psychopathology and personality

Although there are well-established correlates and outcomes of irritability, there are fewer studies reporting on predictors of the longitudinal course of irritability in youth. The current report examined parent internalizing and externalizing psychopathology and dimensions of personality as predictors of the developmental course of irritability in youth. Offspring irritability was assessed between ages 2 and 10 years using the Irritability Factor from the parent-reported Child Behavior Checklist (N = 570, 53.51% female). Parental psychopathology was assessed with a clinical interview; parents also completed the General Temperament Survey as a measure of personality. Results demonstrated that offspring irritability decreased with age. Offspring irritability was associated with parental depressive and anxiety disorders, higher levels of negative emotionality/neuroticism (NE) and disinhibition, and lower levels of positive emotionality; parental NE and disinhibition remained unique predictors of offspring irritability in a multivariate model. Finally, parental externalizing disorders were associated with more stable trajectories of offspring irritability, whereas offspring of parents without a history of externalizing disorders showed decreasing irritability across time. Findings demonstrate that different aspects of parental personality and psychopathology have differential impacts on levels and course of offspring irritability.

Tonic and phasic irritability in 6-year-old children: differential correlates and outcomes

OBJECTIVE

Irritability is a common and clinically important problem in children and adolescents and a risk factor for later psychopathology and impairment. Irritability can manifest in both tonic (e.g., irritable, touchy mood) and phasic (e.g., temper outburst) forms, and recent studies of adolescents suggest that they predict different outcomes. However, no studies have examined whether tonic and phasic irritability are empirically distinguishable in 6-year-old children and whether they have distinct correlates and outcomes.

METHOD

We utilized data from a longitudinal study of an unselected community sample of four hundred fifty-two 6-year-olds followed at 3-year intervals to age 15. We conducted confirmatory factor analysis (CFA) using relevant items from a diagnostic interview and several parent-report inventories.

RESULTS

The CFA identified dimensions that were consistent with tonic and phasic irritability. Tonic irritability was independently associated with concurrent parent-reported temperamental negative affectivity and internalizing and externalizing disorders at age 6 and predicted higher rates of internalizing psychopathology, and suicidal ideation, in adolescence. Phasic irritability was independently associated with concurrent parent-reported temperamental negative affectivity, surgency, and low effortful control, maladaptive parenting styles and practices, and externalizing disorders at age 6, and predicted higher rates of externalizing psychopathology in adolescence.

CONCLUSIONS

Tonic and phasic irritability in 6-year-old children appear to be distinguishable constructs with different temperament and parenting correlates and psychopathological outcomes. Distinguishing these components has implications for research on the etiology and pathophysiology of irritability and developing effective treatments.

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.

Practitioner Review: Attention-deficit hyperactivity disorder and autism spectrum disorder - the importance of depression

Young people with neurodevelopmental disorders, such as attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), show high rates of mental health problems, of which depression is one of the most common. Given that depression in ASD and ADHD is linked with a range of poor outcomes, knowledge of how clinicians should assess, identify and treat depression in the context of these neurodevelopmental disorders is much needed. Here, we give an overview of the latest research on depression in young people with ADHD and ASD, including possible mechanisms underlying the link between ADHD/ASD and depression, as well as the presentation, assessment and treatment of depression in these neurodevelopmental disorders. We discuss the implications for clinicians and make recommendations for critical future research in this area.

Editorial: Roads Less Traveled: New Directions for Novel Outcomes in Youth Irritability Research

Road metaphors are ubiquitous in youth mental health. Developmental psychopathology research is described in terms of pathways, trajectories, cascades, and transitions. Children's behavioral concerns are discussed as warning signs and rough spots. Although these metaphors have long been useful abstractions, modern quantitative methods and large-scale longitudinal studies have made it possible to empirically investigate the "roads" traveled by individuals across development. One goal here is to chart the paths most often followed by different subgroups of youth. Another goal involves surveying variables that nudge children toward (or away from) psychopathology and other key outcomes. These 2 goals-finding trajectories and predictors thereof-have important implications for research, intervention, and policy; and some of the most important studies, in our view, accomplish both.

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.

Examining the impact of ADHD polygenic risk scores on ADHD and associated outcomes: A systematic review and meta-analysis

Early identification of attention-deficit/hyperactivity disorder (ADHD) is critical for mitigating the many negative functional outcomes associated with its diagnosis. Because of the strong genetic basis of ADHD, the use of polygenic risk scores (PRS) could potentially aid in the early identification of ADHD and associated outcomes. Therefore, a systematic search of the literature on the association between ADHD and PRS in pediatric populations was conducted. All articles were screened for a priori inclusion and exclusion criteria, and, after careful review, 33 studies were included in our systematic review and 16 studies with extractable data were included in our meta-analysis. The results of the review were categorized into three common themes: the associations between ADHD-PRS with 1) the diagnosis of ADHD and ADHD symptoms 2) comorbid psychopathology and 3) cognitive and educational outcomes. Higher ADHD-PRS were associated with increased odds of having a diagnosis (OR = 1.37; p<0.001) and more symptoms of ADHD (β = 0.06; p<0.001). While ADHD-PRS were associated with a persistent diagnostic trajectory over time in the systematic review, the meta-analysis did not confirm these findings (OR = 1.09; p = 0.62). Findings showed that ADHD-PRS were associated with increased odds for comorbid psychopathology such as anxiety/depression (OR = 1.16; p<0.001) and irritability/emotional dysregulation (OR = 1.14; p<0.001). Finally, while the systematic review showed that ADHD-PRS were associated with a variety of negative cognitive outcomes, the meta-analysis showed no significant association (β = 0.08; p = 0.07). Our review of the available literature suggests that ADHD-PRS, together with risk factors, may contribute to the early identification of children with suspected ADHD and associated disorders.

Pharmacotherapy of Disruptive Behaviors in Children with Intellectual Disabilities

Disruptive behaviors are a class of predominantly externalizing behaviors that include physical aggression, property destruction, temper outbursts, verbal aggression, and some forms of self-injurious behaviors. Externalizing behaviors are also major components of disruptive, impulse-control and conduct disorders, disruptive mood dysregulation disorder, trauma-related and stressor-related disorders, intermittent explosive disorder, personality disorders, and other neuropsychiatric and neurodevelopmental disorders. Disruptive behaviors and associated disorders are among the most frequent reasons for child behavioral health referrals and are the most common reason for referrals among children with intellectual disabilities. The focus of this paper is on the adjunctive role of integrated psychopharmacological treatment in the management of children with disruptive behaviors and co-occurring intellectual disabilities. The decision-making process for adding pharmacotherapy to a comprehensive treatment plan incorporates not only a working knowledge of basic behavioral neurobiology of disruptive behaviors but also an understanding of the strengths and weaknesses of various pharmacotherapies. Importantly, there is little evidence to support the use of psychopharmacologic agents in managing difficult behaviors in children with intellectual disabilities, but with that said, risperidone has the strongest evidence base for its use.

Psychometric Validation of the Greek Version of the Scale “Temper Loss” of the Questionnaire “Multidimensional Assessment Profile of Disruptive Behavior (MAP-DB)”

It has become increasingly evident that vulnerability to psychopathology is identifiable early in life. A body of evidence suggests that the recognition and prevention of a spectrum of typical/atypical behaviors in preschoolers can lead to earlier diagnosis and treatment. The Multidimensional Assessment Profile of Disruptive Behavior (MAP-DB) is a parent-completed instrument that has been developed recently to differentiate normative misbehaviors in early childhood from markers of clinical risk. The aim of the present study was to validate the “Temper Loss” Subscale in the Greek language and to assess its psychometric properties in healthy children. An on-print parent-report survey was conducted among Greek children, aged between 3 and 5.5 years. The survey included the MAP-DB and the Child Behavior Checklist (CBCL). A total of 400 respondents participated in the study. The analysis suggested that the Greek version of the MAP-DB’s “Temper Loss” scale has good psychometric properties. The results of the Exploratory Factor Analysis (EFA) of the 22 items were able to explain 64.4% of the total variance. Internal consistency for the one subscale was satisfactory, with Cronbach’s alpha at 0.970. This scale can be used by researchers and practitioners for the evaluation of dimensional phenotypes in early childhood.

Genetics in the ADHD Clinic: How Can Genetic Testing Support the Current Clinical Practice?

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with a childhood prevalence of 5%. In about two-thirds of the cases, ADHD symptoms persist into adulthood and often cause significant functional impairment. Based on the results of family and twin studies, the estimated heritability of ADHD approximates 80%, suggests a significant genetic component in the etiological background of the disorder; however, the potential genetic effects on disease risk, symptom severity, and persistence are unclear. This article provides a brief review of the genome-wide and candidate gene association studies with a focus on the clinical aspects, summarizing findings of ADHD disease risk, ADHD core symptoms as dimensional traits, and other traits frequently associated with ADHD, which may contribute to the susceptibility to other comorbid psychiatric disorders. Furthermore, neuropsychological impairment and measures from neuroimaging and electrophysiological paradigms, emerging as potential biomarkers, also provide a prominent target for molecular genetic studies, since they lie in the pathway from genes to behavior; therefore, they can contribute to the understanding of the underlying neurobiological mechanisms and the interindividual heterogeneity of clinical symptoms. Beyond the aforementioned aspects, throughout the review, we also give a brief summary of the genetic results, including polygenic risk scores that can potentially predict individual response to different treatment options and may offer a possibility for personalized treatment for the therapy of ADHD in the future.

Systematic Review: Molecular Studies of Common Genetic Variation in Child and Adolescent Psychiatric Disorders

OBJECTIVE

A systematic review of studies using molecular genetics and statistical approaches to investigate the role of common genetic variation in the development, persistence, and comorbidity of childhood psychiatric traits was conducted.

METHOD

A literature review was performed using the PubMed database, following PRISMA guidelines. There were 131 studies meeting inclusion criteria, having investigated at least one type of childhood-onset or childhood-measured psychiatric disorder or trait with the aim of identifying trait-associated common genetic variants, estimating the contribution of single nucleotide polymorphisms (SNPs) to the amount of variance explained (SNP-based heritability), investigating genetic overlap between psychiatric traits, or investigating whether the stability in traits or the association with adult traits is explained by genetic factors.

RESULTS

The first robustly associated genetic variants have started to be identified for childhood psychiatric traits. There were substantial contributions of common genetic variants to many traits, with variation in single nucleotide polymorphism heritability estimates depending on age and raters. Moreover, genetic variants also appeared to explain comorbidity as well as stability across a range of psychiatric traits in childhood and across the life span.

CONCLUSION

Common genetic variation plays a substantial role in childhood psychiatric traits. Increased sample sizes will lead to increased power to identify genetic variants and to understand genetic architecture, which will ultimately be beneficial to targeted and prevention strategies. This can be achieved by harmonizing phenotype measurements, as is already proposed by large international consortia and by including the collection of genetic material in every study.

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.

Systematic Review: How the Attention-Deficit/Hyperactivity Disorder Polygenic Risk Score Adds to Our Understanding of ADHD and Associated Traits

OBJECTIVE

To investigate, by systematically reviewing the literature, whether the attention-deficit/hyperactivity disorder (ADHD) polygenic risk score (PRS) associates with ADHD and related traits in independent clinical and population samples.

METHOD

PubMed, Embase and PsychoInfo were systematically searched, alongside study bibliographies. Quality assessments were conducted, and a best-evidence synthesis was applied. Studies were excluded when the predictor was not based on the latest ADHD genome-wide association study, when PRS was not based on genome-wide results, or when the study was a review. Initially, 197 studies were retrieved (February 22, 2020), and a second search (June 3, 2020) yielded a further 49 studies. From both searches, 57 studies were eligible, and 44 studies met inclusion criteria.

RESULTS

Included studies were published in the last 3 years. Over 80% of the studies were rated excellent, based on a standardized quality assessment. Evidence of associations between ADHD PRS and the following categories was strong: ADHD, ADHD traits, brain structure, education, externalizing behaviors, neuropsychological constructs, physical health, and socioeconomic status. Evidence for associations with addiction, autism, and mental health were mixed and were, so far, inconclusive. Odds ratios for PRS associating with ADHD ranged from 1.22% to 1.76%; variance explained in dimensional assessments of ADHD traits was 0.7% to 3.3%.

CONCLUSION

A new wave of high-quality research using the ADHD PRS has emerged. Eventually, symptoms may be partly identified based on PRS, but the current ADHD PRS is useful for research purposes only. This review shows that the ADHD PRS is robust and reliable, associating not only with ADHD but many outcomes and challenges known to be linked to ADHD.

A Transdiagnostic Perspective on Youth Irritability

Irritability is increasingly recognized as a significant clinical problem in youth. It is a criterion for multiple diagnoses and predicts the development of a wide range of disorders. Research on etiopathogenesis suggests that genetic and family environmental factors play a role, as do abnormalities in reward and cognitive control circuitry. However, many of these effects are age dependent. Threat-responsive self-regulatory systems and the degree to which irritability manifests as tonic or phasic influence whether irritable youth exhibit more internalizing versus externalizing outcomes.

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.

EARLY PREDICTORS OF ADOLESCENT IRRITABILITY

Limited research has examined precursors/risk factors for adolescent irritability. This study examines continuity of irritability from early childhood to adolescence and identifies antecedents of adolescent irritability. Across self-reports and mother-reports, evidence was found for continuity of irritability. A range of variables assessed at age 3 predicted irritability at age 15. These findings suggest that adolescent irritability is characterized by distinct developmental pathways from age 3 that have potential to result in an irritable phenotype at age 15. Adolescent-reported and mother-reported irritability may be capturing distinct underlying constructs of irritability; both should be considered in assessments of adolescent 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.

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.

Irritability in Mood Disorders: Neurobiological Underpinnings and Implications for Pharmacological Intervention

Feeling irritable is a common experience, both in health and disease. In the context of psychiatric illnesses, it is a transdiagnostic phenomenon that features across all ages, and often causes significant distress and impairment. In mood disorders, irritability is near ubiquitous and plays a central role in diagnosis and yet, despite its prevalence, it remains poorly understood. A neurobiological model of irritability posits that, in children and adolescents, it is consequent upon deficits in reward and threat processing, involving regions such as the amygdala and frontal cortices. In comparison, in adults with mood disorders, the few studies that have been conducted implicate the amygdala, orbitofrontal cortices, and hypothalamus; however, the patterns of activity in these areas are at variance with the findings in youth. These age-related differences seem to extend to the neurochemistry of irritability, with links between increased monoamine transmission and irritability evident in adults, but aberrant levels of, and responses to, dopamine in youth. Presently, there are no specific treatments that have significant efficacy in reducing irritability in mood disorders. However, treatments that hold some potential and warrant further exploration include agents that act on serotonergic and dopaminergic systems, especially as irritability may serve as a prognostic indicator for overall clinical responsiveness to specific medications. Therefore, for understanding and treatment of irritability to advance meaningfully, it is imperative that an accurate definition and means of measuring irritability are developed. To achieve this, it is necessary that the subjective experience of irritability, both in health and illness, is better understood. These insights will inform an accurate, comprehensive, and valid interrogation of the qualities of irritability in health and illness, and allow not only a clinical appreciation of the phenomenon, but also a deeper understanding of its important role within the development and manifestation of mood disorders.

How and Why Are Irritability and Depression Linked?

Based on its course over time, irritability is linked to depression cross-sectionally and longitudinally. Cross-sectionally, irritability takes an episodic form as a symptom in pediatric depression; yet, irritability in the absence of depressed mood or anhedonia is rare. Longitudinally, chronic irritability has been shown to predict depression rather than bipolar disorder or externalizing disorders. Evidence suggests that the link between irritability and depression is explained mostly by shared genetic risk. Both conditions are also associated with higher rates of family history of depression, childhood temperaments and personality styles, and negative parenting styles. The treatment implications are discussed.

Irritability and mood symptoms in adolescent girls: Trait anxiety and emotion dysregulation as mediators

BACKGROUND

Irritability is a common symptom in youth that is thought to be predictive of mood disorders. Its effects on mood are likely to be age-dependent, with direct and indirect mediators. We assessed age-related effects and mediators of irritability in adolescent girls with subthreshold depressive and manic symptoms.

METHODS

We analysed the irritability item from the Mood Disorder Questionnaire in 3 cohorts of girls aged 12-18years (N=229); 12-13years (N=82); 14-15years (N=68); and 16-18years (N=79). They also completed mood, anxiety and emotion regulation questionnaires. MANOVA, correlations and bootstrapped mediation analyses were performed with SPSS®v25 and Hayes Processv3.5®.

RESULTS

Overall, irritable girls had higher depressive and manic symptoms, trait anxiety and emotion dysregulation than those who were not irritable. Significantly higher rates of irritability were observed in mid-adolescents (aged 14-15years; p = 0.001). Notably, irritability exerted effects on depressive symptoms via trait anxiety, non-acceptance of emotions and dysregulation in emotion clarity throughout adolescence. However, irritability directly exerted effects on manic symptoms in mid-adolescence but in older adolescents, their relationship was indirect via impulse control dysregulation.

LIMITATIONS

The cross-sectional design and non-clinical sample limit generalisability of our findings.

CONCLUSIONS

Irritability is involved in subthreshold depressive symptoms, via trait anxiety and perceptual emotion dysregulation. On the other hand, irritability is directly and indirectly associated with subthreshold manic symptoms via dysregulated impulse control depending on age. Therefore, screening for irritability, trait anxiety and emotion dysregulation throughout adolescence may facilitate the early detection of subthreshold depressive and manic symptoms, and the implementation of preventive strategies.

Aggressive outbursts among adults with major depressive disorder: Results from the Collaborative Psychiatric Epidemiological Surveys

INTRODUCTION

Little is known about the epidemiology of aggressive outbursts, including physical assault, property destruction, and verbal aggression, among adults with unipolar Major Depressive Disorder (MDD).

METHODS

We examined the prevalence and correlates of aggressive outbursts among adults with primary MDD (N = 2539) from the Collaborative Psychiatric Epidemiological Surveys (N = 20,013) using generalized linear models.

RESULTS

The prevalence estimate of any aggressive outbursts was 58.7% among adults with MDD. MDD was associated with aggressive outbursts independent of other psychiatric diagnoses. The prevalence of aggressive outbursts differed significantly by age, race/ethnicity, sex, education, marital status, and employment status, and psychiatric diagnoses. Aggressive outbursts were associated with greater severity and earlier age of onset for MDD. Positive associations were also found between the frequency of aggressive outbursts and depressive symptoms including weight/appetite change, fatigue, recurrent thoughts of death. Moreover, aggressive outbursts significantly multiplied the odds of experiencing more severe functional impairment, suicidal ideation, suicide plan, and suicide attempt.

CONCLUSION

Aggressive outbursts are much more common than previously recognized among adults with MDD. The significant association of aggressive outbursts with MDD characteristics, increased functional impairment, and suicidal thoughts and behaviors make them an important target for assessment and treatment for adults with MDD.

Integrating Clinical and Genomic Analyses of Hippocampal-Prefrontal Circuit Disorder in Depression

Major depressive disorder (MDD) is a prevalent, devastating and recurrent mental disease. Hippocampus (HIP)-prefrontal cortex (PFC) neural circuit abnormalities have been confirmed to exist in MDD; however, the gene-related molecular features of this circuit in the context of depression remain unclear. To clarify this issue, we performed gene set enrichment analysis (GSEA) to comprehensively analyze the genetic characteristics of the two brain regions and used weighted gene correlation network analysis (WGCNA) to determine the main depression-related gene modules in the HIP-PFC network. To clarify the regional differences and consistency for MDD, we also compared the expression patterns and molecular functions of the key modules from the two brain regions. The results showed that candidate modules related to clinical MDD of HIP and PFC, which contained with 363 genes and 225 genes, respectively. Ninety-five differentially expressed genes (DEGs) were identified in the HIP candidate module, and 51 DEGs were identified in the PFC candidate module, with only 11 overlapping DEGs in these two regional modules. Combined with the enrichment results, although there is heterogeneity in the molecular functions in the HIP-PFC network of depression, the regulation of the MAPK cascade, Ras protein signal transduction and Ephrin signaling were significantly enriched in both brain regions, indicating that these biological pathways play important roles in MDD pathogenesis. Additionally, the high coefficient protein–protein interaction (PPI) network was constructed via STRING, and the top-10 coefficient genes were identified as hub genes via the cytoHubba algorithm. In summary, the present study reveals the gene expression characteristics of MDD and identifies common and unique molecular features and patterns in the HIP-PFC network. Our results may provide novel clues from the gene function perspective to explain the pathogenic mechanism of depression and to aid drug development. Further research is needed to confirm these findings and to investigate the genetic regulation mechanisms of different neural networks in depression.

Persistence of disruptive mood dysregulation disorder in children with attention-deficit/hyperactivity disorder

Disruptive mood dysregulation disorder (DMDD) is common in children with ADHD yet it is not known how persistent DMDD is in this population. As such we aimed to investigate the persistence of disruptive mood dysregulation disorder (DMDD) in a community sample of children with ADHD. The sample comprised children (n = 136) participating in a cohort study with data available at age 7 and age 10. DMDD status was ascertained using proxy items from the Diagnostic Interview Schedule for Children, Version IV. Of those with DMDD at age 7 (n = 30), eight (21.1%) had DMDD that persisted at age 10. In the first study investigating the longitudinal course of DMDD in ADHD one in five children with ADHD+DMDD at age 7 continued to meet diagnostic criteria for DMDD three years later.

The importance of a developmental perspective in Psychiatry: what do recent genetic-epidemiological findings show?

There is growing appreciation that a developmental perspective is helpful in Psychiatry. However, clinical practice and research, especially in an era of very large sample sizes, often ignore the developmental context. In this perspective piece, we discuss why a developmental view is important in Psychiatry and how recent genetic-epidemiological findings further highlight this. DSM-5 childhood neurodevelopmental disorders such as ADHD, typically onset in early childhood but can persist into adult life; the same ADHD genetic loading appears to contribute across the life course. However, recent longitudinal studies have observed that ADHD symptoms may emerge later during adolescence and adult life in some individuals although the etiology of this late-onset group is unclear. The epidemiology and genetics of depression do not appear to be the same in childhood, adolescence, and adult life. Recent genetic findings further highlight this. Autistic type problems and irritability also appear to show developmental variation in their genetic etiology. These findings raise the question of whether social communication and irritability have the same meaning at different ages. Schizophrenia typically onsets after adolescence. However, it is commonly preceded by childhood antecedents that do not resemble schizophrenia itself but do appear to index schizophrenia genetic liability. We conclude that there is a need for clinicians and scientists to adopt a developmental perspective in clinical practice and research by considering age-at-onset and changes over time as well as different developmental periods when interpreting clinical symptoms.

Irritability Disorders in Adults: Diagnostic Categories Missing in Plain Sight?

Research into irritability has focused largely on its developmental and child-adolescent manifestations. Although irritability appears to be as elemental an experience as anxiety or depression, diagnoses highlighting irritability as the focal ingredient have yet to be delineated for adults. Instead, irritability-related diagnoses in adults have largely emphasized externalizing behaviors, depressed mood, and personality. Consequently, patients complaining of irritability are sometimes shoehorned into diagnostic categories that they do not experience as authentic representations of their lived experiences. This article proposes that the symptom of irritability might be productively reenvisioned as a focal point, analogous to anxiety and depression, around which irritability-related syndromes and disorders in adults might coalesce. If anxiety, depressive, insomnia, and pain disorders, why not irritability disorders? Both state and trait characteristics of irritability can lend themselves to DSM diagnostic frames. Based on clinical observations, specific irritability disorders in adults can be envisioned, modeled as Irritability Disorder of Adulthood, Irritability Disorder Secondary to Another Medical Condition, Substance-Induced Irritability Disorder, Adjustment Disorder With Irritable Mood, and the like. Further delineation of irritability phenomena, syndromes, and possible disorders in adults is warranted to advance investigation, guide assessment, and improve treatment.