Objective: Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) both have psychiatric comorbidities and distinctive profiles of executive dysfunction. Although there is evidence that executive function (EF) plays a role in the expression of specific behaviors and psychiatric symptoms, it is not known whether specific EF deficits in ASD and ADHD may be pathways to comorbidities in the disorders. This study examines whether parent reported problems with flexibility in ASD and inhibition in ADHD mediate the disorders' associations with anxiety/depression and oppositional/aggressive behavior, respectively.
Method: Parent report data from the Behavior Rating Inventory of Executive Function (BRIEF) and the Child Behavior Checklist (CBCL) were obtained for 125 children (70 ASD, 55 ADHD Hyperactive/Impulsive or Combined type) as part of a neuropsychological assessment. Diagnostic status, BRIEF Shift (shifting/flexibility) and Inhibit (behavioral inhibition) scale scores, and CBCL Anxious/Depressed (anxiety/depression) and Aggressive Behavior (oppositionality/aggression) scale scores were analyzed with a path analysis to investigate the relation of flexibility and inhibition to comorbid symptoms in children with ASD and ADHD.
Results: In a path model with good fit ASD predicted greater inflexibility which predicted greater anxiety/depression, while ADHD predicted greater disinhibition that predicted greater aggression, consistent with our mediational hypotheses. Unexpectedly, the greater inflexibility associated with ASD also predicted greater aggression.
Conclusions: Findings support the importance of everyday EF problems in ASD and ADHD as predictors of comorbid psychopathology and as crucial intervention targets for potential prevention and mitigation of comorbid symptoms.
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