Using Item Response Theory to Compare Irritability Measures in Early Adolescent and Childhood Samples

Neural mechanisms of reward processing in preadolescent irritability: Insights from the ABCD study

Elevated youth irritability is characterized by increased proneness to frustration relative to peers when rewards are blocked, and is a transdiagnostic symptom that predicts multiple forms of psychopathology and poorer socioeconomic outcomes in adulthood. Although mechanistic models propose that irritability is the result of aberrant reward-related brain function, youth irritability as it relates to multiple components of reward processes, including reward anticipation, gain, and loss, has yet to be examined in large, population-based samples. Data from the Adolescent Brain and Cognitive Development (ABCD) baseline sample (N = 5923) was used to examine associations between youth irritability (measured by parent-report) and reward-related brain activation and connectivity in a large, preadolescent sample. Preadolescents (M age = 9.96 years, SD = 0.63) performed the Monetary Incentive Delay task during functional MRI acquisition. In the task, during the anticipation period, participants were informed of the upcoming trial type (win money, lose money, no money at stake) and waited to hit a target; during the feedback period, participants were informed of their success. Whole brain and region of interest (ROI) analyses evaluated task conditions in relation to irritability level. Preadolescents with higher compared to lower levels of irritability demonstrated blunted prefrontal cortex activation in the anticipation period and exaggerated striatum-prefrontal connectivity differences among reward conditions during the feedback period. These effects persisted after adjusting for co-occurring anxiety, depression, and attention-deficit/hyperactivity disorder symptoms. These findings provide evidence for the role of reward salience in pathophysiological models of youth irritability, suggesting a mechanism that may contribute to exaggerated behavioral responses.

Irritability and stress: Prospective, bidirectional relationships in adolescence

BACKGROUND

Irritability is a transdiagnostic risk factor for psychopathology and interpersonal problems in youth. However, there is little research on the role of life stress in irritability. The association between stress and irritability may be bidirectional, with irritability leading to stress exposure and stress aggravating irritability. Moreover, it is conceivable that there are sex differences in these relationships. Therefore, we examined the prospective, bidirectional relationships between irritability and stressful life events in a sample of adolescents while considering the role of biological sex.

METHODS

We tested multi-group path models investigating bidirectional associations of irritability with dependent and independent episodic stressors in a community sample of 520 adolescents (52.1 % male) across ages 12, 15, and 18.

RESULTS

All models had acceptable fit. For males, dependent stress at age 12 predicted irritability at age 15, which in turn predicted more stress at age 18. For females, irritability at age 12 predicted dependent stress at age 15, which in turn predicted more irritability at age 18. For independent events in males, irritability at age 15 predicted stress at age 18. For females, independent stress at age 12 predicted irritability at age 15, which in turn predicted more stress at age 18.

CONCLUSION

There are significant bidirectional relationships between irritability and episodic stressors, although the relationships varied depending on youth's age, sex, and role in contributing to stressor occurrence.

Neural mechanisms of inhibitory control in preadolescent irritability: Insights from the ABCD study

OBJECTIVE

Elevated pediatric irritability is a transdiagnostic symptom that predicts multiple mental health problems in adolescence and adulthood. Altered top-down regulatory networks, such as inhibitory control networks that suppress an impulse in favor of goal-directed behavior, are thought to contribute to high levels of youth irritability. Nevertheless, little work has examined links between youth irritability and neural processes supporting inhibitory control in large diverse samples, nor have they focused on the key period ramping up to adolescence (i.e., preadolescence).

METHOD

Functional MRI data from 5380 preadolescents (age M=9.97 years, SD=0.62) in the baseline Adolescent Brain and Cognitive Development (ABCD) Study were analyzed. Parents reported on their preadolescent's irritability. The stop signal task (SST) was leveraged to probe successful and failed inhibitory control. Activation and functional connectivity with amygdala, ventral striatum, and prefrontal seed regions were calculated during the SST and used in whole brain and region of interest (ROI) group-level analyses evaluating irritability effects.

RESULTS

Preadolescents with higher levels of irritability displayed decreases in functional connectivity among amygdala, ventral striatum, and prefrontal cortex regions during both successful and failed inhibitory control conditions. These results remained after adjusting for co-occurring anxiety, depression, and attention-deficit/hyperactivity symptoms.

CONCLUSIONS

Findings suggest neural aberrations in inhibitory control play a role in the pathophysiology of preadolescent irritability and associations are not merely due to co-occurring symptoms. Neural mechanisms of inhibitory control associated with irritability may provide novel intervention targets.

Autistic Symptoms, Irritability, and Executive Dysfunctions: Symptom Dynamics from Multi-Network Models

Socio-cognitive difficulties in individuals with autism spectrum disorder (ASD) are heterogenuous and often co-occur with irritability symptoms, such as angry/grouchy mood and temper outbursts. However, the specific relations between individual symptoms are not well-represented in conventional methods analyzing aggregated autistic symptoms and ASD diagnosis. Moreover, the cognitive-behavioral mechanisms linking ASD to irritability are largely unknown. This study investigated the dynamics between autistic (Social Responsiveness Scale) and irritability (Affective Reactivity Index) symptoms and executive functions (Cambridge Neuropsychological Test Automated Battery) in a sample of children and adolescents with ASD, their unaffected siblings, and neurotypical peers (N = 345, aged 6-18 years, 78.6% male). Three complementary networks across the entire sample were computed: (1) Gaussian graphical network estimating the conditional correlations between symptom nodes; (2) Relative importance network computing relative influence between symptoms; (3) Bayesian directed acyclic graph estimating predictive directionality between symptoms. Networks revealed numerous partial correlations within autistic (rs = .07-.56) and irritability (rs = .01-.45) symptoms and executive functions (rs = -.83 to .67) but weak connections between clusters. This segregated pattern converged in all directed and supplementary networks. Plausible predictive paths were found between social communication difficulties to autism mannerisms and between "angry frequently" to "lose temper easily." Autistic and irritability symptoms are two relatively independent families of symptoms. It is unlikely that executive dysfunctions explain elevated irritability in ASD. Findings underscore the need for researching other mood and cognitive-behavioral bridge symptoms, which may inform individualized treatments for co-occurring irritability in ASD.

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.

Evidence Base Update on the Assessment of Irritability, Anger, and Aggression in Youth

OBJECTIVE

Irritability, anger, and aggression have garnered significant attention from youth mental health researchers and clinicians; however, fundamental challenges of conceptualization and measurement persist. This article reviews the evidence base for assessing these transdiagnostic constructs in children and adolescents.

METHOD

We conducted a preregistered systematic review of the evidence behind instruments used to measure irritability, anger, aggression, and related problems in youth. Searches were conducted in PsycINFO and PubMed, identifying 4,664 unique articles. Eligibility criteria focused on self- and proxy-report measures with peer-reviewed psychometric evidence from studies in English with youths ages 3-18. Additional measures were found through ancillary search strategies (e.g. book chapters, review articles, test publishers). Measures were screened and coded by multiple raters with acceptable reliability.

RESULTS

Overall, 68 instruments met criteria for inclusion, with scales covering irritability (n = 15), anger (n = 19), aggression (n = 45), and/or general overt externalizing problems (n = 27). Regarding overall psychometric support, 6 measures (8.8%) were classified as Excellent, 46 (67.6%) were Good, and 16 (23.5%) were Adequate. Descriptive information (e.g. informants, scales, availability, translations) and psychometric properties (e.g. reliability, validity, norms) are summarized.

CONCLUSIONS

Numerous instruments for youth irritability, anger, and aggression exist with varying degrees of empirical support for specific applications. Although some measures were especially strong, none had uniformly excellent properties across all dimensions, signaling the need for further research in particular areas. Findings promote conceptual clarity while also producing a well-characterized toolkit for researchers and clinicians addressing transdiagnostic problems affecting youth.

Aggression and Irritability in Middle Childhood: Between- and Within-Person Associations

OBJECTIVE

This study tested predicted bidirectional associations between irritability and physical and relational forms of aggression, disentangling theorized within- and between-person effects using latent curve models with structured residuals (LCM-SR) over one year in middle childhood. Gender differences and robustness of results when controlling for other externalizing problems (i.e., attention problems, delinquency) were also considered.

METHOD

Children in third, fourth, and fifth grade (N = 704, 49.9% female) were recruited from schools in a large midwestern city. The sample was diverse in regard to race/ethnicity (31% Black, 29% White, 13% Hmong, 14% Latinx, 4% Native American, 4% Asian, 5% other races/ethnicities). Irritability, attention problems, and delinquency were measured using teacher-report, and physical and relational aggression were measured using self-report at three time points over one calendar year.

RESULTS

At the between-person level, higher mean levels of irritability predicted higher initial levels of physical and relational aggression. Irritability continued to predict higher levels of physical aggression across the course of the study, whereas the effect of irritability on relational aggression diminished. Boys showed higher starting levels of physical aggression, but no other significant gender differences emerged. No significant within-person associations were found.

CONCLUSIONS

The present study suggests that irritability may represent a between-person risk factor for high levels of physical and relational aggression in middle childhood, although effects on physical aggression may be more persistent. This highlights the importance of considering affective processes to understand the development of aggression trajectories.

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

OBJECTIVES

Identification of clinically significant irritability in preschool age is important to implement effective interventions. However, varying informant and measurement methods display distinct patterns. These patterns are associated with concurrent and future mental health concerns. Patterns across multi-informant methods in early-childhood irritability may have clinical utility, identifying risk for impaired psychosocial functioning.

METHODS

Using data from the Multidimensional Assessment of Preschoolers Study (N = 425), latent profile analysis identified irritability patterns through the parent-reported Multidimensional Assessment Profile Scales-Temper Loss (MAPS-TL), parent-reported interviewer-rated Preschool Age Psychiatric Assessment (PAPA), and observer-rated Disruptive Behavior Diagnostic Observation Schedule (DB-DOS). These profiles were characterized on protective factors, global functioning, and mental health syndromes, concurrently and at early school age and preadolescent follow-up.

RESULTS

Fit indices favored a five-class model: Low All, High Observation with Examiner (high DB-DOS Examiner Context), High All, High Parent Report (high MAPS-TL/PAPA), and Very High Parent Report (very high MAPS-TL/PAPA). Whereas Low All and High Observation with Examiner exhibited strong psychosocial functioning, remaining profiles showed impaired psychosocial functioning, with the Very High Parent Report group showing higher impairment at follow-ups, ds = 0.37-1.25.

CONCLUSIONS

Multi-informant measurements of irritability may have utility for clinical prediction, and future studies should test utility for diagnostic precision.

Development and Psychometric Evaluation of the Open-Source Challenging Behavior Scale (OS-CBS)

At present, there are no brief, freely-available, informant-report measures that evaluate key challenging behaviors relevant to youth with autism spectrum disorder (ASD) or other developmental disabilities (DD). This paper describes the development, refinement, and initial psychometric evaluation of a new 18-item measure, the Open-Source Challenging Behavior Scale (OS-CBS). In a large sample (n = 2004, 169 with ASD, ages 2-17), results of psychometric analyses indicated a clear factor structure (property destruction, aggression, elopement, conduct problems, and self-injury and a general factor with high loadings from all items) based on exploratory structural equation modeling, good scale reliability (α = .66-.83 for subscales, α = .91 total scale), measurement invariance across demographics, and good construct validity. The OS-CBS is a psychometrically-sound instrument for screening and monitoring intervention progress.

Transactional associations of child irritability and anxiety with parent psychological control in Taiwanese school-aged children

Background

Child irritability and anxiety are associated with parent psychological control; yet their transactional relations over time are not well-characterized at the within-person level. Research addressing generalizability of past Western-based literature in non-Western, collectivist community samples is lacking.

Methods

Sample comprised 285 children aged 8.8-11.4 years (145 girls; Mage = 9.9 years, SD = 0.6) in Northern Taiwan. Participants were assessed at baseline (T1), 6-month (T2), and 12-month (T3) follow-ups. Child irritability and anxiety symptoms were assessed using parent-rated Child Behavior Checklist. Parent psychological control was assessed using the parent- and child-rated Psychological Control Scale. Within-person processes were specified using the random-intercept cross-lagged panel models.

Results

Models showed that psychological control predicted increased child irritability when analyzing parenting data from parents and children. However, the lagged effect from psychological control to child anxiety was only seen in parent-rated parenting data. We found limited evidence for a back-and-forth transactional pathway among constructs. Child irritability predicted increased child anxiety in all models.

Conclusions

Directional effects from psychological control to child irritability and anxiety support parent-involved interventions that prioritize collaborative parenting and positive reinforcement techniques. Future validations in combined clinical and typically developing samples and direct cross-cultural comparisons are warranted.

A pragmatic, clinically optimized approach to characterizing adolescent irritability: Validation of parent- and adolescent reports on the Multidimensional Assessment Profile Scales-Temper Loss Scale

OBJECTIVES

Heightened irritability in adolescence is an impairing symptom that can lead to negative outcomes in adulthood, but effective screening tools are lacking. This study aimed to derive clinically-optimized cutoff scores using the Multidimensional Assessment Profile Scales-Temper Loss (MAPS-TL) to pragmatically identify adolescents with impairing irritability.

METHODS

A diverse sample of 79 adolescents and their parents completed the MAPS-TL-Youth version. Stepwise logistic regression analyses were used to determine the items associated with impairment, and receiver operator characteristic (ROC) analyses were conducted to derive optimal cutoff scores.

RESULTS

Three parent-report items (become frustrated easily, angry/irritable/grouchy throughout the day, difficulty calming down when angry) and two youth-report items (hit/shove/kick when lost temper, difficulty calming down when angry) were strongly associated with impairment. Optimal cutoff scores garnered very good sensitivity (91%, 73%) and specificity (77%, 75%) for the parent- and youth-report versions respectively. Scores above these cutoffs were associated with increased internalizing and externalizing problems and lower overall quality of life.

CONCLUSIONS

The MAPS-TL clinically optimized irritability scores show preliminary validity for implementation in practical settings to efficiently identify adolescents who need additional evaluation and/or intervention. Further research is important to validate these cutoff scores with larger population-based samples and real-world settings.

Developmentally specified characterization of the irritability spectrum at early school age: Implications for pragmatic mental health screening

OBJECTIVES

Developmentally specified measures that identify clinically salient irritability are needed for early school-age youth to meaningfully capture this transdiagnostic risk factor for psychopathology. Thus, the current study modeled the normal:abnormal irritability spectrum and generated a clinically optimized screening tool for this population.

METHODS

The irritability spectrum was modeled via the youth version of the Multidimensional Assessment Profile Scales-Temper Loss Scale (MAPS-TL-Youth) in children (n = 474; 6.0-8.9 years) using item response theory (IRT). Both cross-cutting core irritability items from the early childhood version and new developmentally specific items were included. Items uniquely associated with impairment were identified and used to derive a brief, clinically optimized irritability screener. Longitudinal data were then utilized to test the predictive utility of this clinically optimized screener in preadolescence (n = 348; 8.0-12.9 years).

RESULTS

Most children exhibit irritability regularly, but daily occurrence was rare. Of the top 10 most severe items from the IRT analyses, 9 were from the developmentally specific items added for the MAPS-TL Youth version. Two items associated with concurrent impairment were identified for the clinically optimized irritability screener ("Become frustrated easily" and "Act irritable"). The MAPS-TL-Youth clinically optimized screener demonstrated good sensitivity (69%) and specificity (84%) in relation to concurrent DSM 5 irritability-related diagnoses. Youth with elevated scores on the screener at early school age (ESA) had more than 7x greater odds of irritability-related psychopathology at pre-adolescence.

CONCLUSIONS

The MAPS-TL-Youth characterized the developmental spectrum of irritability at ESA and a clinically optimized screener showed promise at predicting psychopathology risk. Rigorous testing of clinical applications is a critical next step.

Future Directions in Youth Irritability Research

Research on irritability in children and adolescents has proliferated over the last 20 years. The evidence shows the clinical and developmental significance of irritable mood and behavior in youth, and it has led to significant changes in mental health classification, diagnosis, and services. At the same time, this research (including our own) has led to relatively little new in terms of practical, empirically based guidance to improve interventions and outcomes. In this article, we briefly summarize some of these developments and current evidence-based practices. We then put forth two key substantive challenges (the "whats") for future research to address: (a) the need for more effective treatments, especially evaluating and adapting evidence-based treatments that are already well-established for problems related to irritability (e.g., cognitive-behavioral therapies for internalizing and externalizing problems); and (b) the need for a better mechanistic understanding of irritability's phenomenology (e.g., phasic vs. tonic irritability, how frustration unfolds) and putative underlying mechanisms (e.g., cognitive control, threat and reward dysfunction). Lastly, we suggest three methodological approaches (the "hows") that may expedite progress in such areas: (a) ecological momentary assessment, (b) digital health applications, and (c) leveraging existing datasets. We hope this article will be useful for students and early-career researchers interested in tackling some of these important questions to better meet the needs of severely irritable youth.

Parsing between- and within-person effects: Longitudinal associations between irritability and internalizing and externalizing problems from early childhood through adolescence

INTRODUCTION

This report examines between- and within-person associations between youth irritability and concurrent and prospective internalizing and externalizing symptoms from early childhood through adolescence. Distinguishing between- and within-person longitudinal associations may yield distinct, clinically relevant information about pathways to multifinality from childhood irritability.

METHODS

Children's irritability and co-occurring symptoms were assessed across five waves between ages 3 and 15 years using the mother-reported Child Behavior Checklist (N = 605, 46% female). Parental history of depressive disorders was assessed with a clinical interview.

RESULTS

Results demonstrated that between- and within-person irritability were uniquely associated with concurrent depressive, anxiety, and defiance symptoms, but not ADHD. Prior wave within-person irritability also predicted next wave depressive, anxiety, and defiance symptoms, controlling for prior symptoms; these prospective associations were bidirectional. Child sex and parental depressive disorders moderated associations.

DISCUSSIONS

Findings identify pathways from within- and between-person irritability to later internalizing and externalizing psychopathology. Results demonstrate the importance of parsing within- and between-person effects to understand nuanced relations among symptoms over childhood.

Neural correlates of irritability symptom relief in adolescents pre- and post-trauma-focused cognitive behavioral therapy: A pilot study on reward processing

Despite that Trauma-Focused Cognitive Behavioral Therapy (TF-CBT) is a first-line, evidence-based treatment for youths experiencing trauma-related symptoms, treatment responses vary and it remains unclear for whom and how this treatment works. In this context, we examined pre-treatment neural reward processing and pre- vs. post-treatment changes in neural reward processing, in relation to irritability - a transdiagnostic and dimensional feature present in multiple trauma-related syndromes, following TF-CBT. Adolescents (N = 22) with childhood trauma history completed a child-friendly monetary incentive delay task during fMRI acquisition, prior to and after the treatment, and irritability symptoms were assessed at five time points over the course of the treatment. Individual irritability slopes (i.e., irritability change rate) and intercepts (i.e., initial irritability level), generated by linear growth curve modeling, were integrated with fMRI data. Repeated ANCOVAs demonstrated that both pre-treatment neural response to reward and pre- vs. post-treatment changes in neural reward processing correlated with irritability symptom relief, such that opposite baseline neural reward processing profiles and differential changing patterns were observed in individuals showing irritability symptom relief vs. not. Together, our findings provide proof of concept that integrating brain information with clinical information has the potential to identify predictors and mechanisms of symptom relief.

Robust caregiver-youth discrepancies in irritability ratings on the affective reactivity index: An investigation of its origins

OBJECTIVE

The Affective Reactivity Index (ARI) is widely used to assess young people's irritability symptoms, but youth and caregivers often diverge in their assessments. Such informant discrepancy might be rooted in poor psychometric properties, the differential conceptualization of irritability across informants, or reflect sociodemographic and clinical characteristics. We use an out-of-sample replication approach and leverage longitudinal data, available for a subset of the participants, to test these hypotheses.

METHOD

Across two independent samples (NCohort-1 = 765, 8-21 years; NCohort-2 = 1910, 6-21 years), we investigate the reliability and measurement invariance of the ARI, examine sociodemographic and clinical predictors of discrepant reporting and probe the utility of a bifactor model for cross-informant integration.

RESULTS

Despite good internal consistency and 6-week-retest-reliability of parent (Cohort-1: α = 0.92, ICC = 0.85; Cohort-2: α = 0.93) and youth forms (Cohort-1: α = 0.88, ICC = 0.78; Cohort-2: α = 0.82), we confirm substantial informant discrepancy in ARI ratings (3 points on a scale from 0 to 12), which is stable over six weeks (ICC = 0.53). Measurement invariance across informants was weak, indicating that parents and youth may interpret ARI items differently. Irritability severity and diagnostic status predicted informant-discrepancy, albeit in opposing directions: higher severity was linked to relative, higher irritability-ratings by youth (Cohort-1: β = -0.06, p < .001; Cohort-2: β = -0.06, p < .001), while diagnoses of Disruptive Mood Dysregulation Disorder (Cohort-1: β = 0.44, p < .001; Cohort-2: β = 0.84, p < .001) and Oppositional Defiant Disorder (Cohort-1: β = 0.41, p < .001; Cohort-2: β = 0.42, p < .001) predicted relative higher irritability-ratings by caregivers. In both datasets, a bifactor model parsing informant-specific from shared irritability-related variance fit the data well (CFI = 0.99, RMSEA = 0.05; N2: CFI = 0.99; RMSEA = 0.04).

CONCLUSION

Parent and youth ARI reports and their discrepancy are reliable and reflect different interpretations of the scale items; hence they should not be averaged. This finding also suggests that irritability is not a unitary construct. Future work should investigate and model how different aspects of irritability might differ in their impact on the responses of specific informants.

Cross-sectional and Longitudinal Associations of Anxiety and Irritability With Adolescents' Neural Responses to Cognitive Conflict

BACKGROUND

Psychiatric symptoms are commonly comorbid in childhood. The ability to disentangle unique and shared correlates of comorbid symptoms facilitates personalized medicine. Cognitive control is implicated broadly in psychopathology, including in pediatric disorders characterized by anxiety and irritability. To disentangle cognitive control correlates of anxiety versus irritability, the current study leveraged both cross-sectional and longitudinal data from early childhood into adolescence.

METHODS

For this study, 89 participants were recruited from a large longitudinal research study on early-life temperament to investigate associations of developmental trajectories of anxiety and irritability symptoms (from ages 2 to 15) as well as associations of anxiety and irritability symptoms measured cross-sectionally at age 15 with neural substrates of conflict and error processing assessed at age 15 using the flanker task.

RESULTS

Results of whole-brain multivariate linear models revealed that anxiety at age 15 was uniquely associated with decreased neural response to conflict across multiple regions implicated in attentional control and conflict adaptation. Conversely, irritability at age 15 was uniquely associated with increased neural response to conflict in regions implicated in response inhibition. Developmental trajectories of anxiety and irritability interacted in relation to neural responses to both error and conflict.

CONCLUSIONS

Our findings suggest that neural correlates of conflict processing may relate uniquely to anxiety and irritability. Continued cross-symptom research on the neural correlates of cognitive control could stimulate advances in individualized treatment for anxiety and irritability during child and adolescent development.

Systematic Review and Meta-analysis: Task-based fMRI Studies in Youths With Irritability

OBJECTIVE

Childhood irritability, operationalized as disproportionate and frequent temper tantrums and low frustration tolerance relative to peers, is a transdiagnostic symptom across many pediatric disorders. Studies using task-dependent functional magnetic resonance imaging (fMRI) to probe neural dysfunction in irritability have increased. However, an integrated review summarizing the published methods and synthesized fMRI results remains lacking.

METHOD

We conducted a systematic search using irritability terms and task functional neuroimaging in key databases in March 2021, and identified 30 studies for our systematic review. Sample characteristics and fMRI methods were summarized. A subset of 28 studies met the criteria for extracting coordinate-based data for quantitative meta-analysis. Ten activation-likelihood estimations were performed to examine neural convergence across irritability measures and fMRI task domains.

RESULTS

Systematic review revealed small sample sizes (median = 58, mean age range = 8-16 years) with heterogeneous sample characteristics, irritability measures, tasks, and analytical procedures. Meta-analyses found no evidence for neural activation convergence of irritability across neurocognitive functions related to emotional reactivity, cognitive control, and reward processing, or within each domain. Sensitivity analyses partialing out variances driven by heterogeneous tasks, irritability measures, stimulus types, and developmental ages all yielded null findings. Results were compared with a review on irritability-related structural anomalies from 11 studies.

CONCLUSION

The lack of neural convergence suggests a need for common, standardized irritability assessments and more homogeneous fMRI tasks. Thoughtfully designed fMRI studies probing commonly defined neurocognitive functions may be more fruitful to elucidate the neural mechanisms of irritability. Open science practices, data mining in large neuroscience databases, and standardized analytical methods promote meaningful collaboration in irritability research.

Characterizing the Neural Correlates of Response Inhibition and Error Processing in Children With Symptoms of Irritability and/or Attention-Deficit/Hyperactivity Disorder in the ABCD Study®

Attention-deficit/hyperactivity disorder (ADHD), characterized by symptoms of inattention and/or hyperactivity and impulsivity, is a neurodevelopmental disorder associated with executive dysfunctions, including response inhibition and error processing. Research has documented a common co-occurrence between ADHD and pediatric irritability. The latter is more characterized by affective symptoms, specifically frequent temper outbursts and low frustration tolerance relative to typically developing peers. Shared and non-shared neural correlates of youths with varied profiles of ADHD and irritability symptoms during childhood remain largely unknown. This study first classified a large sample of youths in the Adolescent Brain Cognitive Development (ABCD) study at baseline into distinct phenotypic groups based on ADHD and irritability symptoms (N = 11,748), and then examined shared and non-shared neural correlates of response inhibition and error processing during the Stop Signal Task in a subset of sample with quality neuroimaging data (N = 5,948). Latent class analysis (LCA) revealed four phenotypic groups, i.e., high ADHD with co-occurring irritability symptoms (n = 787, 6.7%), moderate ADHD with low irritability symptoms (n = 901, 7.7%), high irritability with no ADHD symptoms (n = 279, 2.4%), and typically developing peers with low ADHD and low irritability symptoms (n = 9,781, 83.3%). Latent variable modeling revealed group differences in the neural coactivation network supporting response inhibition in the fronto-parietal regions, but limited differences in error processing across frontal and posterior regions. These neural differences were marked by decreased coactivation in the irritability only group relative to youths with ADHD and co-occurring irritability symptoms and typically developing peers during response inhibition. Together, this study provided initial evidence for differential neural mechanisms of response inhibition associated with ADHD, irritability, and their co-occurrence. Precision medicine attending to individual differences in ADHD and irritability symptoms and the underlying mechanisms are warranted when treating affected children and families.

Irritability-related neural responses to frustrative nonreward in adolescents with trauma histories: A preliminary investigation

Irritability, conceptualized as a lowered frustration response threshold to blocked goal attainment (i.e., frustrative nonreward), is a common, detrimental symptom in adolescence. Yet, neural mechanisms of irritability are not well understood. This preliminary study aims to identify irritability-related neural patterns using a novel frustrative nonreward paradigm. Our study used a diverse sample of N = 31 non-White adolescent participants (mean age 14.53 years, SD = 1.74; 83.87% Hispanic/Latinx) to improve generalizability. During fMRI acquisition, participants performed a child-friendly monetary incentive delay task, modified to provide incorrect, negative feedback on performance. Irritability was associated with alterations in amygdala connectivity with basal ganglia, prefrontal, temporal, and parietal regions, and in activation of prefrontal and posterior cortical structures. Across clusters, youths with greater irritability showed activation/connectivity differences between reward blocked versus received conditions in the opposite direction compared to youths with lowered irritability. Alterations in amygdala-temporoparietal connectivity and lingual gyrus activation demonstrated an altered irritability-related recovery effect from the previous trial. These findings support the central role of frustrative nonreward as a key irritability pathway. Our work is one of the first to document neural correlates of difficult recovery from frustration characteristic of irritability and provides insight into novel treatment targets for irritability in diverse populations.

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

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

Measurement and correlates of irritability in clinically referred youth: Further examination of the Affective Reactivity Index

BACKGROUND

Research on youth irritability has proliferated in recent years, largely facilitated by items from existing measures and by key new instruments like the Affective Reactivity Index (ARI). The present study extends this literature by investigating the psychometric properties of the parent- and youth-report ARI and the correlates of irritability in an independent, clinically referred sample.

METHOD

Baseline assessment data were collected from 237 youths (ages 3-18; 36% female) and their parents, seen for outpatient therapy and/or assessment. We examined the ARI in terms of (1) its item, scale, and factor properties; (2) convergent/discriminant validity with internalizing, externalizing, and emotion regulation problems; (3) specificity of associations with reactive aggression, anger, dysregulation, and coping; and (4) robustness of associations after controlling for demographic variables (e.g., age, gender).

RESULTS

The ARI's internal consistency and unidimensional factor structure were acceptable or better, with some variation across items and informants. Irritability, as measured by parent- and youth-report, was associated with variables in the externalizing (inattention, hyperactivity, executive dysfunction, aggression), internalizing (anxiety, depression, suicidality), and emotion regulation domains. Associations with reactive aggression, anger, dysregulation, and coping problems were especially pronounced. Irritability's links with internalizing and externalizing problems remained robust after controlling for demographic covariates.

LIMITATIONS

The sample was limited in diversity and moderate in size.

CONCLUSIONS

Findings support the reliability and validity of the ARI for assessing parent- and youth-rated irritability among clinically referred youth. Future research is needed to understand variations in irritability's manifestations, measurement, and correlates across demographic groups.

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.