The Impact of Co-Occurring Autism and ADHD on Social Impairment

Autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) are neurodevelopmental disorders that can significantly impact social functioning. ASD is characterized by persistent deficits in social communication and interaction, as well as restricted and repetitive patterns of behavior or interests.

Autistic individuals may struggle with social reciprocity, nonverbal communication, and developing and maintaining relationships. ADHD, on the other hand, is marked by inattention, hyperactivity, and impulsivity. People with ADHD may have difficulty waiting their turn, interrupting others, and maintaining friendships due to impulsive behaviors.

Both disorders can lead to social challenges, such as difficulty understanding social cues, engaging in reciprocal interactions, and maintaining friendships.

Harkins, C. M., Handen, B. L., & Mazurek, M. O. (2022). The impact of the comorbidity of ASD and ADHD on social impairment. Journal of Autism and Developmental Disorders, 52(6), 2512-2522. https://doi.org/10.1007/s10803-021-05150-1

Key Points

1. The main findings of this study on social impairment in children with ASD, ADHD, and ASD+ADHD include:
   • No significant differences in social impairment were found between the ASD and ASD+ADHD groups using the ADOS-2 SA-CSS and ABC Lethargy/Social Withdrawal subscale.
   • The ASD and ASD+ADHD groups scored significantly higher on the ADOS-2 SA-CSS than the ADHD group, indicating greater social impairment.
   • The ABC Lethargy/Social Withdrawal subscale did not yield significant differences across the three diagnostic groups, suggesting it captures convergent social symptoms attributed to either ASD or ADHD.
   • The research, while informative, has limitations such as unequal sample sizes across diagnostic groups and variability in participant age.
2. Understanding social impairment in ASD, ADHD, and their co-occurrence is crucial for accurate diagnosis and effective intervention.

Rationale

Previous research has demonstrated that children with autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) experience significant social difficulties (Barkley, 1998; Cervantes et al., 2013).

When these disorders co-occur, an additive effect on symptom expression has been observed (Ames & White, 2011; Factor et al., 2017). However, limited research has focused on the specific impact of ASD+ADHD comorbidity on social functioning, and existing studies have reported inconsistent findings (Factor et al., 2017; Rao & Landa, 2014; Salley et al., 2015).

These inconsistencies may be attributed to differences in sample characteristics and assessment tools used to measure social impairment.

The present study aims to address these limitations by evaluating group differences in social impairment among a large, well-characterized sample of children with ASD, ADHD, and ASD+ADHD using both clinician- and parent-reported measures.

Understanding the social profiles of these diagnostic groups is essential for developing targeted interventions and improving outcomes for affected individuals.

Method

The study utilized data from a previously completed study comparing DSM-IV and DSM-5 criteria for ASD. Participants were 282 children (ages 2-17) diagnosed with ASD (n = 151), ADHD (n = 82), or ASD+ADHD (n = 49) who underwent a comprehensive diagnostic evaluation at one of six autism centers.

Procedure

Participants were recruited before their evaluation and underwent a standard diagnostic process, including record review, standardized observation using the ADOS-2, cognitive assessment, and additional measures as needed.

Sample

The sample consisted of 282 children (82.27% male) with a mean age of 93.12 months (SD=50.46). Participants were predominantly White (80.85%) and non-Hispanic (85.46%).

Measures

• ADOS-2 Social Affect Calibrated Severity Score (SA-CSS): A clinician-observed measure of social impairment that assesses the child’s social communication and interaction skills, such as eye contact, facial expressions, and social overtures, during standardized activities. The SA-CSS provides a standardized severity score that allows for comparison across different ADOS-2 modules and age groups.
• Aberrant Behavior Checklist (ABC) Lethargy/Social Withdrawal subscale: A caregiver-reported measure of social impairment that evaluates the child’s social withdrawal, lack of energy, and reduced interest in their surroundings. The subscale consists of 16 items rated on a 4-point scale, with higher scores indicating greater impairment in social functioning.
• Cognitive assessments: Various measures, such as the Wechsler Intelligence Scales, Stanford-Binet Intelligence Scales, and Mullen Scales of Early Learning, were used to assess the child’s cognitive abilities, including verbal and nonverbal skills, depending on their age and ability level. These assessments provide an estimate of the child’s overall intellectual functioning, which is an important factor to consider when interpreting social impairment scores.

Statistical Measures

Data were transformed due to skewed distributions and missing data were replaced using multiple imputation. MANCOVA was used to compare diagnostic groups on measures of social impairment, with age and IQ as covariates.

Results

The study hypothesized that the ASD+ADHD group would exhibit the highest degree of social impairment, followed by the ASD and ADHD groups.

MANCOVA results revealed significant differences between diagnostic groups on the ADOS-2 SA-CSS, with the ASD and ASD+ADHD groups scoring significantly higher than the ADHD group (p<.001).

However, no significant differences were found between the ASD and ASD+ADHD groups on the ADOS-2 SA-CSS. Additionally, no significant group differences were observed on the ABC Lethargy/Social Withdrawal subscale.

Age was a significant covariate (p<.001), while IQ was not (p=.227). These findings suggest that children with ASD and ASD+ADHD display similar levels of social impairment when assessed using the ADOS-2 SA-CSS, and that the ABC Lethargy/Social Withdrawal subscale may capture convergent social symptoms attributed to either ASD or ADHD.

The results highlight the importance of using multiple assessment methods to evaluate social functioning in these diagnostic groups.

Insight

This study provides valuable insights into the social profiles of children with ASD, ADHD, and ASD+ADHD.

The finding that children with ASD and ASD+ADHD exhibit similar levels of social impairment on the ADOS-2 SA-CSS suggests that the core social deficits observed in ASD may not be significantly worsened by the presence of ADHD.

However, the lack of significant group differences on the ABC Lethargy/Social Withdrawal subscale indicates that this parent-report measure may be capturing convergent social symptoms attributed to either disorder.

These findings underscore the importance of using multiple assessment methods, including both clinician observation and parent report, to comprehensively evaluate social functioning in these populations.

The study extends previous research by using a large, well-characterized sample and employing both clinician- and parent-reported measures of social impairment.

The results contribute to the understanding of the ASD+ADHD phenotype and have implications for diagnostic assessment and intervention planning.

Future research should investigate potential age-related differences in symptom presentation and explore the role of executive functioning in the social difficulties observed in these diagnostic groups.

Strengths

Below are some of the methodological strengths of this study:

• Large, well-characterized sample of children with ASD, ADHD, and ASD+ADHD
• Use of both clinician-observed (ADOS-2 SA-CSS) and caregiver-reported (ABC Lethargy/Social Withdrawal) measures of social impairment
• Comprehensive diagnostic evaluations conducted by autism specialists in accordance with standard ATN diagnostic process
• Inclusion of age and IQ as covariates in statistical analyses
• Rigorous data transformation and multiple imputation methods to address skewed distributions and missing data

Limitations

Below are some of the methodological limitations of this study:

• Unequal sample sizes across diagnostic groups, with the ASD+ADHD group having the smallest sample size (n=49)
• Wide age range of participants (2-17 years), which may have contributed to variability in symptom presentation
• Potential differences in social demands across ADOS-2 modules, which could have impacted results despite the use of calibrated severity scores
• All participants were initially referred for an ASD evaluation, suggesting that social impairment in the ADHD group may have been more significant than in the general ADHD population
• Lack of comprehensive assessment data on co-occurring conditions and limited IQ data for some participants

The limitations of this study highlight the need for future research with more balanced sample sizes, participants matched on age and ADOS-2 module, and more representative samples of children with ADHD.

Additionally, comprehensive assessment data on co-occurring conditions and cognitive functioning should be included to better understand the factors influencing social impairment in these diagnostic groups.

Implications

The results of this study have significant implications for the assessment and treatment of social impairment in children with ASD, ADHD, and ASD+ADHD.

The finding that children with ASD and ASD+ADHD display similar levels of social impairment on the ADOS-2 SA-CSS suggests that social interventions targeting core deficits in ASD may be similarly effective for children with ASD+ADHD.

However, the lack of significant group differences on the ABC Lethargy/Social Withdrawal subscale highlights the importance of using multiple assessment methods to comprehensively evaluate social functioning and tailor interventions accordingly.

The study’s findings also underscore the need for clinicians to consider the potential impact of ADHD symptoms on social functioning of autistic children and to screen for co-occurring ADHD in this population.

Early identification and intervention for both disorders may be crucial for improving social outcomes and overall quality of life.

Furthermore, the study’s limitations, such as the wide age range of participants and potential differences in social demands across ADOS-2 modules, emphasize the need for future research to investigate age-related differences in symptom presentation and to control for potential confounding variables.

Longitudinal studies examining the developmental trajectories of social impairment in these diagnostic groups could provide valuable insights into the factors influencing social outcomes over time.

References

Primary reference

Harkins, C. M., Handen, B. L., & Mazurek, M. O. (2022). The impact of the comorbidity of ASD and ADHD on social impairment. Journal of Autism and Developmental Disorders, 52(6), 2512-2522. https://doi.org/10.1007/s10803-021-05150-1

Other references

Ames, C. S., & White, S. J. (2011). Brief report: Are ADHD traits dissociable from the autistic profile? Links between cognition and behaviour. Journal of Autism and Developmental Disorders, 41(3), 357–363. https://doi.org/10.1007/s10803-010-1049-0

Barkley, R. A. (1998). Attention-deficit hyperactivity disorder. Scientific American, 279(3), 66–71. https://doi.org/10.3928/0048-5713-19891101-08

Cervantes, P. E., Matson, J. L., Adams, H. L., Williams, L. W., Goldin, R. L., & Jang, J. (2013). Comparing social skill profiles of children with autism spectrum disorders versus children with attention deficit hyperactivity disorder: Where the deficits lie. Research in Autism Spectrum Disorders, 7(9), 1104–1110. https://doi.org/10.1016/j.rasd.2013.05.008

Factor, R. S., Ryan, S. M., Farley, J. P., Ollendick, T. H., & Scarpa, A. (2017). Does the presence of anxiety and ADHD symptoms add to social impairment in children with autism spectrum disorder? Journal of Autism and Developmental Disorders, 47(4), 1122–1134. https://doi.org/10.1007/s10803-016-3025-9

Rao, P. A., & Landa, R. J. (2014). Association between severity of behavioral phenotype and comorbid attention deficit hyperactivity disorder symptoms in children with autism spectrum disorders. Autism, 18(3), 272–280. https://doi.org/10.1177/1362361312470494

Salley, B., Gabrielli, J., Smith, C. M., & Braun, M. (2015). Do communication and social interaction skills differ across youth diagnosed with autism spectrum disorder, attention-deficit/hyperactivity disorder, or dual diagnosis? Research in Autism Spectrum Disorders, 20, 58–66. https://doi.org/10.1016/j.rasd.2015.08.006

Keep Learning

Here are some reflective questions related to this study that could prompt further discussion:

1. How might the social profiles of autistic children, ADHD, and ASD+ADHD differ across various developmental stages (e.g., preschool, school-age, adolescence)?
2. What are the potential mechanisms underlying the social difficulties observed in autistic children, ADHD, and ASD+ADHD (e.g., executive functioning, social cognition, language skills)?
3. How can clinicians effectively differentiate between social impairments attributed to core ASD deficits versus those resulting from ADHD symptoms or other co-occurring conditions?
4. How can future research address the limitations of the current study and provide a more comprehensive understanding of the factors influencing social impairment in these diagnostic groups?