Developmental trajectories of irritability during the transition to adolescence: Examining caregiver and youth perspectives and sex differences

Background: Irritability is a leading reason for referral to child and adolescent mental health services. However, longitudinal studies on the development of irritability rely exclusively on caregiver reports, yielding limited insights into youth experiences and potential sex differences during the transition to adolescence. Methods: Using data from the ABCD Study (N=9411, 48% females), this study compared caregiver and youth reports of irritability from ages 9 to 13, with a focus on persistent high irritability (≥2 'very true' and ≥1 'somewhat true' ratings of hot temper across time points) and sex differences. Results: Persistent high irritability was observed in 5.1% of youth, compared to 1.6% of caregivers. Agreement between informants across irritability trajectories (‘low’, ‘low-to-moderate’, ‘moderate’, and ‘high’) was low, Cohen’s κ = 0.09, p<.001, particularly among girls. When girls reported persistent high irritability, only 3.9% of their caregivers did so, compared to 9.5% among boys. Conclusions: These findings underscore the importance of incorporating youth self-report – especially for females – as sole reliance on caregiver reports may overlook key aspects of youth’s development of irritability.