Assessment of Attention-Deficit/Hyperactivity Disorder in Young Autistic Children

Co-occurring attention-deficit/hyperactivity disorder (ADHD) is present for many autistic children and is associated with increased impairments, unique treatment needs, and decreased response to autism-specific interventions. Diagnosing ADHD in autistic children during the preschool and early school-age periods presents unique challenges for clinicians.

This work describes a clinically informed diagnostic framework for assessing ADHD in young autistic children. Clinical complexities are illustrated using descriptive data from caregiver and clinician ratings of ADHD symptoms in autistic children without ADHD (n = 83; mean age 63.6 months [SD = 19.2]) and with ADHD (n = 102; mean age 85.9 months [SD = 23.7]). Patterns of caregiver and clinician symptom endorsement are described. Logistic regression is employed to explore clinician confidence in diagnostic decision-making.

Clinical interview probes are presented to help clinicians explore caregiver ratings of ADHD symptoms in the context of an autistic child's presentation. Demonstrating the complexity of diagnosing ADHD in autistic children, caregiver-rated ADHD Rating Scale scores were elevated for both the autistic (M = 27.8; SD = 11.5) and autistic+ADHD groups (M = 34.9; SD = 9.37). Patterns of clinician-caregiver agreement on ADHD symptom ratings showed more disagreement on inattention items than on hyperactivity/impulsivity items across both groups. Clinicians were more confident in ADHD diagnosis in autistic children who were girls, older, and had higher developmental levels.

This manuscript highlights the clinical complexity of evaluating young autistic children for ADHD. Practical tips for addressing the unique challenges of diagnosing ADHD in autistic children are presented. Continued refinement and future validation of this diagnostic framework will help clinicians improve assessment of young children.