Clinical characteristics of children with ASD and comorbid ADHD: Association with social impairment and externalizing and internalizing behaviours.

Dellapiazza et al. (2021) compared three groups of school-age kids: ASD plus ADHD, ADHD only, and neurotypical peers.

They used rating scales and interviews to map social skills, acting-out behaviors, and internalizing problems like worry or withdrawal.

The goal was to see if the combo group looked different from the single-diagnosis kids.

The ASD+ADHD group showed the worst social impairment, worse than ADHD-only and typical peers.

Acting-out tracked with how severe the ADHD symptoms were, while withdrawn or anxious moods tracked with ASD severity.

In short, each diagnosis kept its own “signature” problems, and together they piled up.

Ohan et al. (2015) already showed that kids with both conditions score lower on daily living and social skills; Florine extends that by showing which diagnosis drives which problem.

McIntyre et al. (2017) found that even ADHD symptoms (not full diagnosis) worsen social scores in ASD; Florine confirms and sharpens the picture using full diagnoses and parent reports.

Rosello et al. (2022) pooled 34 studies and reached the same bottom line—more impairment when ASD and ADHD meet—so Florine’s 2021 data sit right inside that bigger wave.

Crisci et al. (2026) will add a twist: half of each single-diagnosis group actually share the same “social deficits plus behavior dysregulation” profile, reminding us to look at the child, not just the label.

When a child carries both ASD and ADHD, expect social struggles above the ADHD-only level, and know that acting-out usually comes from ADHD severity while mood withdrawal comes from ASD severity. Tailor your plan: teach social skills, but also target self-control or anxiety depending on which driver is louder that day.