A new study comparing children with autism, ADHD, and symptoms of both reveals that comorbid conditions can alter the relationship between cognitive abilities and emotional and behavioral regulation, providing new insights into why children with both diagnoses require better assessment and intervention strategies.
study: Cognitive and emotional profiles of children with ASD, ADHD, and comorbid conditions: Evidence for distinct clinical phenotypes. Image credit: Pixel-Shot/Shutterstock.com
In recent research, frontiers of psychiatry investigated the cognitive and emotional behavioral profiles of children with ASD, ADHD, and both disorders to determine whether comorbid conditions may represent distinct clinical phenotypes that require individualized assessment and intervention approaches.
Clinical overlap and comorbidity between ASD and ADHD
ASD and ADHD are highly prevalent neurodevelopmental disorders that begin in childhood and persist throughout life. 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 adjustment disorders, often leading to academic, social, and behavioral problems.
Both ASD and ADHD exhibit deficits in executive function (EF). ASD is associated with a wide range of EF deficits, including cognitive inhibition and planning, whereas ADHD exhibits significant deficits in inhibitory control, attention span, and regulation. ADHD is primarily associated with externalizing symptoms (e.g., aggression, rule-breaking), whereas ASD is associated with internalizing traits (e.g., social withdrawal, emotional flattening).
Epidemiological data reveal that up to 70% of children with ASD meet criteria for ADHD, and 30–50% of children with ADHD exhibit autistic features. Previous studies have demonstrated symptom overlap and common neurobiological mechanisms between ASD and ADHD, complicating differential diagnosis and raising questions about comorbidity and phenotypic boundaries.
ASD and ADHD frequently co-occur, but remain poorly characterized and underdiagnosed, resulting in misclassification, suboptimal interventions, and increased systemic burden. Determining whether ASD+ADHD are distinct neurodevelopmental phenotypes or an additive syndrome is essential for diagnostic accuracy and targeted treatments.
Recent large-scale genomic studies have highlighted pleiotropy across neurodevelopmental phenotypes, supporting the dimensional model. It is essential to identify disorder-specific factors that contribute to ASD+ADHD being distinct or overlapping phenotypes. Methodological deficiencies limit our understanding of whether comorbid groups are distinct phenotypes or additive syndromes.
Assessment of cognitive and behavioral profiles of ASD, ADHD, and ASD+ADHD groups
The current study investigated the cognitive and behavioral-emotional profiles of children with ASD, ADHD, and ASD+ADHD comorbidity. The researchers hypothesized that the ASD+ADHD group would exhibit pervasive behavioral-emotional dysregulation with lower working memory, processing speed, and full-scale IQ, as well as increased internalizing and externalizing symptoms.
They also proposed that cognitive ability correlates with behavioral outcomes in ASD and ADHD, but not in ASD+ADHD, indicating that the typical relationship between cognitive ability and emotional behavioral regulation in comorbid groups may be disrupted.
A total of 207 children and adolescents aged 6 to 16 years were assessed using the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) and the Child Behavior Checklist (CBCL 6-18). Based on the assessment, they were retrospectively assigned to three groups: ASD (n = 21), ADHD (n = 103), and ASD+ADHD (n = 83).
Distinctive cognitive and behavioral patterns revealed in ASD, ADHD, and comorbid cohorts
Demographic analyzes showed comparable gender distribution across all groups, with the ASD+ADHD group having a slightly younger mean age. Cognitive profiles did not reveal group differences in language 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 the ADHD group.
This indicates that on cognitive measures, the comorbid group showed a profile closer to ADHD than to ASD, whereas behavioral findings showed a broader and more mixed pattern across symptom domains. The biggest impact was seen on overall cognitive function.
The behavioral profile of the CBCL showed that the ASD group had higher social withdrawal/depression scores, reflecting greater social withdrawal and depressed mood. The ADHD group showed the highest levels of rule-breaking and aggressive behavior, as well as externalizing symptoms, distinguishing them from other groups. No significant differences between groups were found for internalizing or overall behavioral symptom severity.
On DSM-oriented CBCL scales, the ADHD and ASD+ADHD groups had more ADHD and conduct-related problems than ASD alone. Supplementary measures revealed that cognitive tempo slowness and obsessive-compulsive problems were more pronounced in ASD and ASD+ADHD compared to ADHD. The largest effect sizes were observed for externalizing problems, aggressive behavior, and conduct-related problems.
Correlational analyzes demonstrated that in both the ADHD and ASD groups, improvements in cognitive abilities, particularly language comprehension, working memory, and overall IQ, were associated with reductions in behavioral and emotional problems, particularly in the areas of attention, social functioning, and mood regulation.
In ASD, stronger cognitive skills were consistently associated with better academic performance and social functioning, as well as fewer behavioral/emotional problems, particularly attention and physical symptoms. In ASD+ADHD, cognitive function had a low association with behavioral symptoms, but a moderate association with school. Performance and overall ability were maintained. Unusually, higher language scores were weakly associated with more opposing symptoms, suggesting unique dynamics in the comorbid group.
conclusion
Children with both ASD and ADHD tended to exhibit cognitive and behavioral characteristics that partially overlap 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 show the highest levels of externalizing symptoms. Although strong cognitive skills appear to help buffer behavioral and emotional challenges in the individual cases of ASD and ADHD, 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 and highlight the need for tailored approaches in assessment and intervention for this potentially distinct clinical group. However, the authors caution that conclusions regarding discrete phenotypes are preliminary and should be confirmed in larger studies with more comprehensive clinical and demographic data.
The researchers also noted several limitations that may limit the generalizability of the findings, including the relatively small ASD-only sample, retrospective cross-sectional design, and reliance on parent-reported behavioral measures.
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