One of the most
controversial comorbidities in children with ASD is the co-occurrence of
Attention Deficit Hyperactivity Disorder (ADHD). Comorbidity refers to the
presence of more than one diagnosis occurring in an individual at the same
time. Although there continues to a debate about ADHD comorbidity in ASD,
research, practice and theoretical models suggest that comorbidity between
these disorders is relevant and occurs frequently. For example, a study of
comorbid psychiatric disorders in children with ASD found that approximately
71% of cases had a least one comorbid psychiatric disorder, with the most
common comorbidities being social anxiety (29%), ADHD (28%), and Oppositional
Defiant Disorder (28%). Although the current DSM-IV-TR hierarchical rules
prohibit the concurrent diagnosis of ASD/PDD and ADHD, there is a relatively
high frequency of impulsivity and inattention in children with ASD. In fact,
ADHD is a relatively common initial diagnosis in young children with ASD. Some
researchers suggest that there are sub-groups of children with ASD with and without
ADHD symptoms.
Current Research
Although comorbid
psychiatric disorders in children with ASD have been studied previously, there
is a need to examine the impact of co-occurring ADHD symptoms in children with
ASD. A recent study published in the journal Pediatrics
evaluated the frequency of co-occurring ADHD symptoms in a well-defined cohort
of children with ASD and examined the relationship between ADHD symptoms and
both adaptive functioning and health-related quality of life as reported by
parents or other primary caregivers. The purpose of the study was to: (a)
document the frequency of parent-reported ADHD symptoms in a large, geographically
diverse population of children with ASD, and (b) further evaluate the differences
between children with ASD and ADHD symptoms and those with few or no ADHD
symptoms, with an emphasis on parent-report measures of adaptive functioning
and health-related quality of life (HRQoL). Based on a review of previous
studies, the researchers hypothesized that children with ASD and comorbid ADHD
symptoms would have poorer HRQoL and greater impairment in adaptive functioning
than children with ASD and few or no ADHD symptoms.
Current Research
Method and Outcome
Measures
The research was conducted
as part of the activities of the Autism Speaks Autism Treatment Network (ATN),
a registry collecting data on children with ASD across 14 sites in the United
States and Canada. A total of 3066 children and adolescents ages 2 to 18 were eligible
for participation in the study. All participants had a clinical diagnosis of
ASD based on one or more diagnostic measures.
Parents completed the Child
Behavior Checklist (CBCL), a parent/caregiver measure of a variety of problems
exhibited during childhood. T-scores on 2 ADHD-related scales from the CBCL were
used to indicate the presence of ADHD symptoms. Participants were divided into
groups based on whether their parents/caregivers rated them as having
clinically significant T-scores on the Attention Problem and Attention Deficit
Hyperactivity Problem subscales of the CBCL. Parents were interviewed to
complete the Vineland Adaptive Behavior Scales, Second Edition (VABS-II). Standard
scores from VABS-II and raw scores from the parent report version of Pediatric
Quality of Life Inventory (PedsQL) were then compared between groups with the
use of multivariate analyses.
Results
Results indicated that 41%
of the 3,000 participants had elevated scores on one CBCL ADHD-related subscale
and 19% on both subscales. Analysis of responses to the PedsQL revealed that
the ASD/ADHD group had lower scores in all health-related areas measured (School
Functioning, Physical Functioning, Emotional Functioning, and Social Functioning)
in comparison with the group of children with ASD alone. The ASD/ADHD group
also obtained statistically significantly lower scores on all adaptive behavior
domains of the VABS-II (Communication, Daily Living Skills, Socialization, and
Adaptive Composite) when compared with the group of children with only ASD.
Conclusion and
Implications
Overall results of the
study suggest greater impairment in adaptive functioning and a poorer
health-related quality of life for children with ASD and clinically significant
ADHD symptoms in comparison with children with ASD and fewer ADHD symptoms. This
supports previous research on the negative relationship between ADHD symptoms
and the development of functional life and other adaptive skills and provides further
documentation regarding the relationship between comorbid symptoms and overall
health-related quality of life. The results also suggest the need for
additional research. For example, it would be important to determine if
children with ASD that meet diagnostic criteria for ADHD differ significantly
from children with ASD and ADHD symptoms in the areas of adaptive skill
development and HRQoL, as well as other important areas. This question is
particularly important with the impending publication of DSM-V which will
remove the restriction on the comorbid ADHD diagnosis in children with ASD.
These results of the study
have important implications for practitioners in health care, mental health,
and educational contexts. Externalizing behavior problems, including ADHD
symptoms, have been found to have a strong negative relationship with family
functioning and parenting stress in children with ASD. Reducing ADHD symptoms
in children with ASD, in addition to treating core symptoms, may result in greater
improvement in HRQoL and adaptive functioning. Improving adaptive functioning
is especially important in that a child’s level of adaptive functioning can
directly influence their type of educational setting and future adjustment. Children
with better adaptive skills have more opportunity to participate in grade-level
activities with typical peers. Consequently, clinicians and health-care professionals
should screen for symptoms of ADHD in children with ASD and, if present,
consider these symptoms when developing interventions and treatment protocols.
Sikora, D. M., Vora, P.,
Coury, D. L., & Rosenberg, D. (2012). Attention-Deficit/Hyperactivity
Disorder Symptoms, Adaptive Functioning, and Quality of Life in Children With
Autism Spectrum Disorder. Pediatrics,
130, S91-97. DOI: 10.1542/peds.2012-0900G
Kuhlthau K., Orlich F.,
Hall T.A., et al. (2010). Health- Related Quality of Life in children with autism
spectrum disorders: results from the autism treatment network. Journal of Autism and
Developmental Disorders, 40(6), 721–729.
Murray M.J., (2010).
Attention-deficit/hyperactivity disorder in the context of autism spectrum
disorders. Current
Psychiatry Reports, 12(5), 382–388.
Lee A. Wilkinson, PhD,
CCBT, NCSP is author of the award-winning book, A
Best Practice Guide to Assessment and Intervention for Autism and Asperger Syndrome
in Schools, published by Jessica Kingsley Publishers. He is also the editor of a recent volume in the APA School Psychology Book Series, Autism
Spectrum Disorder in Children and Adolescents: Evidence-Based Assessment and
Intervention in Schools and author of the new book, Overcoming
Anxiety and Depression on the Autism Spectrum: A Self-Help Guide Using CBT.