Oppositional defiant and conduct disorder behaviors in boys with autism spectrum disorder with and without attention-deficit hyperactivity disorder versus several comparison samples.

Guttmann-Steinmetz et al. (2009) compared oppositional defiant behaviors in boys with ASD plus ADHD, ASD only, ADHD only, and typical controls.

Teachers and parents filled out rating scales. The team asked: do adults see the same ODD picture when autism is also present?

Teachers saw a unique, more severe ODD pattern in boys who had both ASD and ADHD.

Parents did not pick up that same difference; their scores looked alike across ADHD groups.

In short, the setting and the rater changed the story.

Reus et al. (2013) later showed the same rater split: parents and interviews inflate autism severity when ADHD is present, but direct observation does not.

Berenguer et al. (2018) added a "double-hit" picture—kids with both diagnoses show compounded executive-function and theory-of-mind deficits, giving a reason teachers may see tougher behavior.

Green et al. (2015) seems to disagree: in a community sample, children labeled ADHD showed medium-level autism traits. The clash fades when you notice Leigh pulled kids from regular schools while Sarit worked with clinic-referred boys; source and severity of symptoms differ.

Always gather teacher and parent data before calling a child oppositional. If the school shows a sharp ODD spike and home does not, check for hidden ADHD inside ASD. Use that mismatch to guide your functional assessment and to build setting-specific supports instead of one-size-fits-all behavior plans.