A new study comparing children with autism, ADHD, and both conditions reveals that comorbidity may alter how cognitive abilities relate to emotional and behavioral regulation, offering new insight into why children with both diagnoses may require more tailored assessment and intervention strategies.
Study: Cognitive and emotional profiles in children with ASD, ADHD, and comorbid presentations: evidence for a distinct clinical phenotype. Image credit: Pixel-Shot/Shutterstock.com
A recent study in Frontiers in Psychiatry investigated the cognitive and emotional-behavioral profiles of children with ASD, ADHD, and those with both conditions, to determine whether comorbidity may represent a distinct clinical phenotype requiring tailored assessment and intervention approaches.
Clinical Overlap and Comorbidity of ASD and ADHD
ASD and ADHD are highly prevalent neurodevelopmental disorders that begin in childhood and persist across the lifespan. ASD is defined by deficits in social communication and restricted, repetitive behaviors, while ADHD is characterized by persistent patterns of inattention, hyperactivity, and impulsivity. Both conditions are associated with significant cognitive, emotional, and adaptive impairments, often resulting in academic, social, and behavioral challenges.
Both ASD and ADHD exhibit executive function (EF) deficits. ASD is associated with broad EF impairments, including cognitive inhibition and planning, while ADHD shows pronounced deficits in inhibitory control, sustained attention, and regulation. ADHD is primarily linked to externalizing symptoms (e.g., aggression, rule-breaking), while ASD is associated with internalizing traits (e.g., social withdrawal, affective flattening).
Epidemiological data have revealed that up to 70% of children with ASD meet ADHD criteria, and 30–50% of children with ADHD exhibit autistic traits. Previous studies have shown overlapping symptomatology and shared neurobiological mechanisms of ASD and ADHD, which complicates differential diagnosis and raises questions about comorbidity and phenotype boundaries.
Although ASD and ADHD frequently co-occur, it remains poorly characterized and underdiagnosed, resulting in misclassification, suboptimal interventions, and increased systemic burden. Clarifying whether ASD+ADHD is a distinct neurodevelopmental phenotype or an additive syndrome is essential for diagnostic accuracy and targeted treatment.
Recent large-scale genomic research highlighted pleiotropy across neurodevelopmental phenotypes, supporting a dimensional model. It is imperative to determine disorder-specific factors that contribute to ASD+ADHD being a distinct or overlapping phenotype. Methodological shortcomings have limited the understanding of whether the comorbid group is a discrete phenotype or an additive syndrome.
Assessing Cognitive and Behavioral Profiles in ASD, ADHD, and ASD+ADHD Groups
The current study investigated cognitive and behavioral-emotional profiles in children with ASD, ADHD, and comorbid ASD+ADHD. Researchers hypothesized that the ASD+ADHD group would display lower working memory, processing speed, and full-scale IQ, alongside broader behavioral-emotional dysregulation with elevated internalizing and externalizing symptoms.
They also proposed that cognitive abilities would correlate with behavioral outcomes in ASD and ADHD, but not in ASD+ADHD, indicating a potential disruption in the typical relationship between cognitive abilities and emotional-behavioral regulation in the comorbid group.
A total of 207 children and adolescents, between 6 and 16, were assessed using the Wechsler Intelligence Scale for Children – Fourth Edition (WISC-IV) and the Child Behavior Checklist (CBCL 6–18). Based on the assessments, they were retrospectively assigned into three groups: ASD (n = 21), ADHD (n = 103), and ASD+ADHD (n = 83).
Distinct Cognitive and Behavioral Patterns Uncovered in ASD, ADHD, and Comorbid Cohorts
Demographic analyses indicated comparable sex distribution across all groups, with the ASD+ADHD group exhibiting a marginally younger mean age. In the cognitive profile, no group differences emerged for verbal comprehension or perceptual reasoning. The ASD+ADHD group showed significantly lower working memory, processing speed, and full-scale IQ compared to the ASD group, but the results were similar to those of the ADHD group.
This indicates that on cognitive measures, the comorbid group showed a profile more similar to ADHD than ASD, while behavioral findings showed a broader and more mixed pattern across symptom domains. The largest effect was seen in global cognitive functioning.
CBCL behavioral profiles showed that the ASD group had higher withdrawn/depressed scores, reflecting greater social withdrawal and low mood. The ADHD group exhibited the highest rule-breaking and aggressive behaviors, as well as externalizing symptoms, distinguishing them from the other groups. No significant group differences were found for internalizing or total behavioral symptom severity.
On DSM-oriented CBCL scales, ADHD and ASD+ADHD groups had higher ADHD and conduct-related problems than ASD alone. Supplementary scales revealed that Sluggish Cognitive Tempo and Obsessive–Compulsive Problems were more prominent in ASD and ASD+ADHD, compared to ADHD. The most substantial effect sizes were observed for externalizing problems, aggressive behavior, and conduct-related problems.
Correlation analyses demonstrated that in both ADHD and ASD groups, greater cognitive abilities, particularly verbal comprehension, working memory, and overall IQ, were associated with reduced behavioral and emotional problems, especially in the domains of attention, social functioning, and mood regulation.
In ASD, stronger cognitive skills were consistently associated with better academic performance and social functioning and fewer behavioral/emotional issues, particularly attention and somatic symptoms. In ASD+ADHD, cognitive functioning showed fewer associations with behavioral symptoms, but moderate links with school performance and overall competence remained; unusually, higher verbal scores were weakly associated with more oppositional symptoms, suggesting unique dynamics in the comorbid group.
Conclusions
Children with both ASD and ADHD tended to show cognitive and behavioral characteristics that partly overlapped with those seen in ADHD, particularly in cognitive domains such as working memory, processing speed, and overall IQ. However, contrary to expectations, they did not exhibit the highest levels of externalizing symptoms. While strong cognitive skills appeared to help buffer against behavioral and emotional challenges in ASD and ADHD individually, this protective role was less evident in children with both conditions.
These findings suggest that the co-occurrence of ASD and ADHD may disrupt the typical relationship between cognitive abilities and emotional-behavioral regulation, highlighting the need for tailored approaches in assessment and intervention for this potentially distinct clinical group. However, the authors caution that conclusions about a discrete phenotype remain tentative and should be confirmed in larger studies with more comprehensive clinical and demographic data.
The researchers also note several limitations, including a relatively small ASD-only sample, a retrospective cross-sectional design, and reliance on parent-reported behavioral measures, which may limit the generalizability of the findings.
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