Callous-unemotional (CU) traits represent a risk factor for persistent, severe levels of externalizing problems. Irritability may predict the development of CU traits for some individuals, who are thought to acquire them in reaction to negative environmental experiences. Models on the development of CU traits have emphasized the socializing role of harsh parenting to the neglect of negative peer experiences. The present study 1) tested primary and alternative models of physical and relational peer victimization as socialization agents in relations between irritability and CU traits; and 2) considered hypothalamic-pituitary-adrenal-axis functioning as a moderator of these associations. Gender moderation was also considered. Aims were tested from middle childhood to adolescence using data from the NICHD Study of Early Child Care and Youth Development, which includes a large national sample (N = 1,077) and multiple methods and informants for the constructs of interest. Positive associations between irritability, peer victimization, and CU traits were supported, with indirect effects on CU traits supported specifically from peer victimization through increases in irritability. Associations between relational victimization, irritability, and CU traits may be particularly salient for females, whose experiences have been neglected to date. However, effects were small, and replication efforts are needed.

Autism spectrum disorder (ASD) is a neurodevelopmental condition. Omega-3 fatty acid insufficiency has been linked to ASD. This umbrella meta-analysis was performed to investigate the effects of omega-3 supplementation on clinical manifestations in participants with ASD. Based on the PRISMA statement, databases including Web of Science, PubMed and Scopus were systematically searched for published meta-analyses on the effect of omega-3 supplementation on ASD up to December 2023. To assess the risk of bias, the assessment of multiple systematic reviews (AMSTAR)-2 was utilised. The outcomes were core and non-core symptoms of ASD including social withdrawal/lethargy, cluttering speech, hyperactivity, irritability and stereotypy. Seven meta-analyses eventually remained in the umbrella review. The results revealed that omega-3 fatty acid supplementation caused a significant reduction in cluttering speech in studies conducted on age ≤8 years (effect size (ES) −0·30; 95% confidence interval (CI) −0·55, −0·06; P = 0·02). Omega-3 supplementation caused a significant reduction in hyperactivity in participants ≤8 years (ES −0·30; 95% CI −0·55, −0·06; P = 0·02) and in participants who received the supplements for more than 14 weeks (ES −0·30; 95% CI −0·55, −0·06; P = 0·02). A dosage of ≤1000 mg/d of omega-3 supplementation led to a significant increase in the stereotypy/restricted and repetitive interests and behaviours (ES 0·19; 95% CI 0·03, 0·35; P = 0·02). This umbrella review revealed that omega-3 fatty acid may be a beneficial supplement to control cluttering speech and hyperactivity in children with ASD who are 8 years old or younger.

We evaluated the effectiveness and tolerability of brivaracetam (BRV), an adjunctive antiseizure medication, as a treatment for focal epilepsy in adults. In this prospective study, we enrolled 51 participants from 3 sites across Canada. At 6 months, 68% (26/38) of participants were still taking BRV, among whom 35% (8/23) attained seizure freedom and 48% (11/23) saw their seizure frequency reduced by over 50%. We did not measure any significant change in irritability, quality of life, depression, and anxiety while treated with BRV. Our findings suggest BRV is effective in reducing seizure frequency among adults with focal epilepsy.

In the general population, irritability is associated with later depression. Despite irritability being more prevalent in autistic children, the long-term sequelae are not well explored. We tested whether irritability in early childhood predicted depression symptoms in autistic adolescents, and whether associations could be explained by difficulties in peer relationships and lower educational engagement. Analyses tested the longitudinal associations between early childhood irritability (ages 3–5) and adolescent depression symptoms (age 14) in a prospective inception cohort of autistic children (N = 390), followed from early in development shortly after they received a clinical diagnosis. Mediators were measured in mid-childhood (age 10) by a combination of measures, from which latent factors for peer relationships and educational engagement were estimated. Results showed early childhood irritability was positively associated with adolescent depression symptoms, and this association remained when adjusting for baseline depression. A significant indirect pathway through peer relationships was found, which accounted for around 13% of the association between early childhood irritability and adolescent depression, suggesting peer problems may partially mediate the association between irritability and later depression. No mediation effects were found for education engagement. Results highlight the importance of early screening and intervention for co-occurring irritability and peer problems in young autistic children.

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

Childhood exposure to intimate partner violence (IPV) can have lasting effects on well-being. Children also display resilience following IPV exposure. Yet, little research has prospectively followed changes in both maladaptive and adaptive outcomes in children who experience IPV in early life. The goal of the current study was to investigate how child factors (irritability), trauma history (severity of IPV exposure), maternal factors (mental health, parenting), and early intervention relate to trajectories of behavior problems (internalizing and externalizing problems) and resilience (prosocial behavior, emotion regulation), over 8 years. One hundred twenty mother-child dyads participated in a community-based randomized controlled trial of an intervention for IPV-exposed children and their mothers. Families completed follow-up assessments 6–8 months (N = 71) and 6–8 years (N = 68) later. Although intention-to-treat analyses did not reveal significant intervention effects, per-protocol analyses suggested that participants receiving an effective dose (eight sessions) of the treatment had fewer internalizing problems over time. Child irritability and maternal parenting were associated with both behavior problems and resilience. Maternal mental health was uniquely associated with child behavior problems, whereas maternal positive parenting was uniquely associated with child resilience. Results support the need for a dyadic perspective on child adjustment following IPV exposure.

Irritability, characterized by anger in response to frustration, is normative in childhood. While children typically show a decline in irritability from toddlerhood to school age, elevated irritability throughout childhood may predict later psychopathology. The current study (n = 78) examined associations between trajectories of irritability in early childhood (ages 2–7) and irritability in adolescence (age 12) and tested whether these associations are moderated by parenting behaviors. Results indicate that negative emotion socialization moderated trajectories of irritability – relative to children with low stable irritability, children who exhibited high stable irritability in early childhood and who had parents that exhibited greater negative emotion socialization behaviors had higher irritability in adolescence. Further, negative parental control behavior moderated trajectories of irritability – relative to children with low stable irritability, children who had high decreasing irritability in early childhood and who had parents who exhibited greater negative control behaviors had higher irritability in adolescence. In contrast, positive emotion socialization and control behaviors did not moderate the relations between early childhood irritability and later irritability in adolescence. These results suggest that both irritability in early childhood and negative parenting behaviors may jointly influence irritability in adolescence. The current study underscores the significance of negative parenting behaviors and could inform treatment.

Irritability is a transdiagnostic symptom dimension in developmental psychopathology, closely related to the Research Domain Criteria (RDoC) construct of frustrative nonreward. Consistent with the RDoC framework and calls for transdiagnostic, developmentally-sensitive assessment methods, we report data from a smartphone-based, naturalistic ecological momentary assessment (EMA) study of irritability. We assessed 109 children and adolescents (Mage = 12.55 years; 75.20% male) encompassing several diagnostic groups – disruptive mood dysregulation disorder (DMDD), attention-deficit/hyperactivity disorder (ADHD), anxiety disorders (ANX), healthy volunteers (HV). The participants rated symptoms three times per day for 1 week. Compliance with the EMA protocol was high. As tested using multilevel modeling, EMA ratings of irritability were strongly and consistently associated with in-clinic, gold-standard measures of irritability. Further, EMA ratings of irritability were significantly related to subjective frustration during a laboratory task eliciting frustrative nonreward. Irritability levels exhibited an expected graduated pattern across diagnostic groups, and the different EMA items measuring irritability were significantly associated with one another within all groups, supporting the transdiagnostic phenomenology of irritability. Additional analyses utilized EMA ratings of anxiety as a comparison with respect to convergent validity and transdiagnostic phenomenology. The results support new measurement tools that can be used in future studies of irritability and frustrative nonreward.

Emotion dysregulation is cross-diagnostic and impairing. Most research has focused on dysregulated expressions of negative affect, often measured as irritability, which is associated with multiple forms of psychopathology and predicts negative outcomes. However, the Research Domain Criteria (RDoC) include both negative and positive valence systems. Emerging evidence suggests that dysregulated expressions of positive affect, or excitability, in early childhood predict later psychopathology and impairment above and beyond irritability. Typically, irritability declines from early through middle childhood; however, the developmental trajectory of excitability is unknown. The impact of excitability across childhood on later emotion dysregulation is also yet unknown. In a well-characterized, longitudinal sample of 129 children studied from ages 3 to 5.11 years through 14 to 19 years, enriched for early depression and disruptive symptoms, we assessed the trajectory of irritability and excitability using multilevel modeling and how components of these trajectories impact later emotion dysregulation. While irritability declines across childhood, excitability remains remarkably stable both within and across the group. Overall levels of excitability (excitability intercept) predict later emotion dysregulation as measured by parent and self-report and predict decreased functional magnetic resonance imaging activity in cognitive emotion regulation regions during an emotion regulation task. Irritability was not related to any dysregulation outcome above and beyond excitability.

Irritability is a transdiagnostic feature of diverse forms of psychopathology and a rapidly growing literature implicates the construct in child maladaptation. However, most irritability measures currently used are drawn from parent-report questionnaires not designed to measure irritability per se; furthermore, parent report methods have several important limitations. We therefore examined the utility of observational ratings of children's irritability in predicting later psychopathology symptoms. Four-hundred and nine 3-year-old children (208 girls) completed observational tasks tapping temperamental emotionality and parents completed questionnaires assessing child irritability and anger. Parent-reported child psychopathology symptoms were assessed concurrently to the irritability assessment and when children were 5 and 8 years old. Children's irritability observed during tasks that did not typically elicit anger predicted their later depressive and hyperactivity symptoms, above and beyond parent-reported irritability and context-appropriate observed anger. Our findings support the use of observational indices of irritability and have implications for the development of observational paradigms designed to assess this construct in childhood.

Irritability is a transdiagnostic phenomenon that, despite its ubiquity and significant impact, is poorly conceptualised, defined and measured. As it lacks specificity, efforts to examine irritability in adults by using a diagnostic category perspective have been hamstrung. Therefore, using a Research Domain Criteria (RDoC) approach to examine irritability in adults, which spans many constructs and domains, may have a better chance of yielding underlying mechanisms that can then be mapped onto various diagnostic categories. Recently, a model has been proposed for irritability in children and adolescents that uses the RDoC framework; however, this model, which accounts for chronic, persistent irritability, may not necessarily transpose to adults. Therefore, use of the RDoC framework to examine irritability in adults is urgently needed, as it may shed light on this currently amorphous phenomenon and the many disorders within which it operates.