Line-Item Analysis of the Aberrant Behavior Checklist: Results from Two Studies of Aripiprazole in the Treatment of Irritability Associated with Autistic Disorder

Objectives: The aim of this study was to evaluate the efficacy of aripiprazole in the treatment of discrete symptoms of irritability associated with autistic disorder, as well as other symptoms captured on the Aberrant Behavior Checklist (ABC). Methods: This was a post hoc analysis of data from two 8-week, randomized, double-blind, multicenter trials to evaluate the efficacy of aripiprazole dosed flexibly (2-15 mg/day, n=47) or fixed (5, 10, or 15 mg/day, n=166) versus placebo (flexibly dosed, n=51; fixed dose, n=52). The effects of treatment on the 58 ABC items were evaluated. Results: Statistically significantly greater improvement was seen with aripiprazole versus placebo (p<0.05) for all arms in both trials on the ABC-Irritability total subscale score and on the following individual ABC-Irritability items: Mood changes quickly, cries/screams inappropriately, and stamps feet/bangs objects. Several additional items measuring tantrum-like behaviors improved in the flexibly dosed trial and at least one arm of the fixed-dose trial (p<0.05). Measures of self-injurious behavior, which had low baseline values, demonstrated numerical, but not statistically significant, improvement in both trials. Statistically significantly greater improvement in ABC Stereotypic Behavior and Hyperactivity total subscale scores was also consistent across all arms in both trials. In particular, there was a cluster of items related to hyperkinesis that were consistently sensitive to treatment. Conclusions: Aripiprazole is efficacious in the treatment of irritability in children and adolescents with autistic disorder, particularly with respect to symptoms associated with tantrum behavior.