A Novel Assessment Tool for Impulsive Aggression in Children with Attention-Deficit/Hyperactivity Disorder

Objective: To establish the validity and reliability of a provisional 30-item impulsive aggression (IA) diary in children (ages 6–12 years, inclusive) with attention-deficit/hyperactivity disorder (ADHD). Methods: The provisional 30-item IA diary was administered for 14 days to parents of children with ADHD and IA symptoms (n = 103). Key inclusion criteria: confirmed ADHD diagnosis; signs of IA as measured by a Retrospective-Modified Overt Aggression Scale (R-MOAS) score ≥20 and an Aggression Questionnaire score of −2 to −5. Analyses included inter-item correlations, exploratory factor analysis (EFA), item response theory (IRT) modeling, internal consistency, test–retest reliability (TRT), concurrent validity (estimated by correlation between the IA diary and the R-MOAS/Nisonger Child Behavior Rating Form), and known-groups methods. Results: The prevalence rates of 15 (50.0%) items were found to be too low (<1%) for analysis; three items with prevalence rates ≤1% were retained, as content validity was deemed high by clinical experts. The remaining 12 behavior items had prevalence rates of 2.7%–73.6%. EFA and IRT models confirmed two subdomains in the IA diary included within a general domain of IA behavior frequency, yielding a single total behavioral frequency score (TBFS). Internal consistency was high for this TBFS (marginal reliability = 0.86 and α = 0.73). TRT for the TBFS, based on the intraclass correlation coefficient, was 0.8. Concurrent validity of TBFS with R-MOAS ranged from r = 0.49 to r = 0.62. Conclusion: The final 15-item IA diary is a reliable, psychometrically validated IA measurement tool that will allow clinicians and researchers to assess the frequency of IA behavior.