Rachel Lawson, Alison A. Papadakis, Ph.D., Christopher I. Higginson, Ph.D., Jeffrey Barnett, Psy.D., ABPP, Meagan C. Wills, John F. Strang, Gregory L. Wallace, Lauren Kenworthy

Specific Executive Function Impairments Predict Comorbid Psychopathology in ASD and ADHD

Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) are often comorbid with specific psychiatric presentations, and they also exhibit unique profiles of impairments in executive functions (EF). Research suggests that EF can play a role in the expression of psychiatric symptoms, but there is a paucity of research exploring whether EF impairments in ASD and ADHD may serve as pathways to common comorbidities in the disorders. The current study hypothesized that the prominent EF impairments in ASD and ADHD mediate the behavioral and psychiatric comorbidities in these disorders, such that impairments with flexibility/shifting in ASD and with inhibition in ADHD mediate the disorders’ associations with anxiety/depression symptoms and oppositional/aggressive behavior, respectively. 

Method: Archival, parent-report data from the Behavior Rating Inventory of Executive Function (BRIEF) and the Child Behavior Checklist (CBCL) were obtained for 125 children (55 ADHD Combined or Hyperactive/Impulsive type, 70 ASD) evaluated at a children’s hospital in the mid-Atlantic. Data were analyzed using path analysis.

Results: Results supported a slightly modified model, χ²(2)= 2.527, p = .283; CFI = .997, RMSEA = .046, SRMR = .039. Children with ASD exhibited significantly more inflexibility than those with ADHD, which predicted greater anxiety/depression symptoms. Children with ADHD exhibited significantly more behavioral disinhibition than those with ASD, which partly predicted oppositionality/aggression; however, ADHD diagnosis alone remained predictive of oppositionality/aggression. Unexpectedly, inflexibility in ASD also predicted oppositionality/aggression.

Conclusions: Findings support the presence of distinct EF impairment profiles in ASD and ADHD and suggest that these impairments may serve as pathways to comorbid psychopathology. Results indicate that EF impairments warrant clinical attention as targets of intervention for possible prevention and/or mitigation of comorbidities.