Impact of ADHD symptoms on autism spectrum disorder symptom severity.
ADHD symptoms inflate parent and interview autism scores, so always rule out ADHD before setting autism severity or dosage levels.
01Research in Context
What this study did
Reus et al. (2013) compared two groups of kids already diagnosed with autism. One group also had ADHD. The other did not.
Parents filled out the SRS and ADI-R. A clinician gave the ADOS. The team then looked at whether the ADHD-plus-autism group scored higher on autism scales.
What they found
Kids who had both autism and ADHD earned higher parent-report and interview scores for autism severity.
On the direct observation test (ADOS) the two groups looked the same. The extra ADHD symptoms only inflated the paperwork numbers, not the live coding.
How this fits with other research
Green et al. (2015) repeated the idea in reverse. They started with kids who had ADHD and found those children also showed more autism traits on parent forms. The pattern holds in both directions.
Tonizzi et al. (2022) went deeper. Their meta-analysis showed that when autism and ADHD travel together, executive-function and adaptive-skill scores drop lower than in autism alone. So the higher parent scores in Linda’s study likely reflect real added struggle, not just rating error.
McGonigle et al. (2014) extended the picture to emotions. Preschoolers with both diagnoses had more depressive and somatic complaints than kids with autism only. The same comorbidity that inflates autism scores also amplifies internalizing signs.
Why it matters
Before you trust an SRS or ADI-R total, screen for ADHD. If parents rate autism traits high but the child does not look severe in session, check off-task and impulsive items. Consider splitting treatment plans: add ADHD supports such as movement breaks and reinforcement for on-task behavior. This keeps you from over-estimating autism severity and under-serving a treatable second condition.
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02At a glance
03Original abstract
Despite the official exclusion criteria for autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) in the DSM-IV and ICD-10, patients with ASD often show ADHD symptoms. We aimed to examine the potential influence of ADHD symptoms on autistic psychopathology in a large sample of patients with ASD. We tested the hypothesis that patients with ASD and an additional ADHD (ASD+) would show a higher severity of autistic symptoms than those with ASD only (ASD-). We measured autistic symptoms using the autism diagnostic observation schedule (ADOS-G), the autism diagnostic interview (ADI-R), and the social responsiveness scale (SRS). To measure overall psychopathology and ADHD symptoms, we used the child behavior checklist (CBCL) and the ADHD rating scale (FBB-ADHS), respectively. Group differences between the ASD+ and the ASD- group (group division was conducted according to the results of the FBB-ADHS) were calculated using a univariate analysis of variance (ANOVA). The ASD+ group showed a greater severity of autistic symptoms than the ASD- group, measured by the SRS and the ADI-R. Especially in the social interaction subscale (ADI-R), a significantly higher symptom severity was found in the ASD+ group. No significant group differences were found regarding autistic symptoms measured by the ADOS-G. Patients with ASD and an additional ADHD expressed a stronger severity of autistic symptoms than patients with ASD only. According to our results, the possibility of a co-diagnosis of ADS and ADHD, as is being planned in the DSM-5, is in line with earlier studies, is highly reasonable, will simplify research, and have therapeutic implications.
Research in developmental disabilities, 2013 · doi:10.1016/j.ridd.2013.07.028