Irritability as a Transdiagnostic Construct Across Childhood and Adolescence: A Systematic Review and Meta-analysis.

This meta-analytic review examined irritability across childhood and adolescence as it relates to symptoms of common mental health disorders in these periods. Of key interest was whether the relationship between irritability and symptom severity varies according to symptom domain. This was tested at the level of broad symptom dimensions (internalizing versus externalizing problems) as well as discrete diagnostic domains (e.g., anxiety, depression, oppositional defiant disorder, conduct disorder, attention deficit hyperactivity disorder; autism spectrum disorder). Following PRISMA guidelines, a systematic search of five databases was conducted to identify studies reporting on associations between irritability and mental health symptoms in samples of children aged 2-18 years. Meta-analytic tests based on random effects models examined concurrent and longitudinal associations between irritability and symptom severity. Meta-regression tested potential moderators including symptom domain, child age, sex, informant type, and study quality. 119 studies met inclusion criteria with a total of 122,456 participants. A significant and positive association was found between irritability and severity of concurrent overall psychopathology in the order of a moderate effect size, while small to moderate effect sizes characterized the association between irritability and later mental health outcomes in prospective data. Further variation in this association was seen across specific diagnostic domains and methodological moderators. Findings support the conceptualization of irritability as a transdiagnostic construct reflecting emotion dysregulation across diverse forms of psychopathology in childhood and adolescence. Further research into the risk mechanisms underlying irritability is needed, in addition to translational approaches to early intervention.