Could ADHD Rates Among People With Autism Be Wrong?

Could ADHD Rates Among People With Autism Be Wrong?

ADHD and OCD are frequent co-occurring conditions diagnosed in populations with autism. Short consult times and pressure on healthcare providers make it difficult to provide accurate diagnosis of ADHD, in particular when ADHD and autism expression in children share some of the same behavioral conditions. The projected rates of ADHD among populations with autism may not be accurate and therefore proposed treatments may not assist those who are diagnosed with but do not have ADHD. What are the findings and issues around testing for ADHD? Are new tests necessary? Explore the issues and challenges surrounding ADHD diagnosis in those with ASD or autism.

Study results published in the Journal of Autism and Developmental Disorders as of October 13th uncover evidence that may show children with autism are being over-diagnosed with ADHD. Understand the importance of this study and how it may impact autism and ADHD diagnosis and treatment.

New Research Sheds Light on Testing

The research team that includes one of the psychologists responsible for designing the ADHD screening tool has come to the conclusion that the screening tools needs additional refinement and results should be supplemented with careful clinical interviews. The researchers from CHOP, Baylor University and the Perelman School of Medicine at the University of Pennsylvania collaborated on this study. Study leader, Benjamin E. Yerys, PhD, researcher in the Center for Autism Research at Children’s Hospital of Philadelphia (CHOP), said:

“One of our best current screening measures for ADHD may be over-diagnosing ADHD in children with autism. This is important because medications that work for ADHD may be less effective for a child on the autism spectrum.”

Scores are used not only for determining treatment options but also in forming recommendations for school-based services. Currently, it is estimated that about 30 percent or more of youth diagnosed with ASD also experience ADHD.

The team analyzed the ADHD Rating Scale Fourth Edition (ADHD-RS-IV) and determined that it may not be an accurate diagnostic tool for those with ASD, although it is well-validated for use in the general population of children. These findings and a review of current testing tools many enhance diagnostic capabilities for researchers and healthcare professionals. Study co-author, Thomas J. Power, PhD, director of CHOP’s Center for Management of ADHD, said:

“I’m excited to be involved in this study, and in efforts to refine our screening tools, especially since few researchers have previously investigated using this scale in children with ASD. Our research raises questions not only about this rating tool, but all such measures that rely on parent and teacher ratings to assess ADHD in children with ASD.”

In the study, 386 children from ages 7 to 17 who had ASD with no intellectual disability participated. Factor analysis was used to test validity of the ADHD rating scale. Some questions put forth on the given scale were high for this population rather than being high for children only with significant ADHD symptoms. The way in which questions are being asked may also skew testing results, as in “Does the child respond when spoken to directly?” As verbal communication can be significantly impaired in those with ASD and autism, a negative response may provide little indication of whether or not a child has symptoms of ADHD. Other ADHD rating scale questions may not provide an accurate picture of understanding of social interactions, focus on a task and problems with social play that are often key features of those with ASD.

Study Team Recommendations

Researchers believe that it would be useful to modify the rating scale to minimize ASD influences. Also, it would benefit clinicians to use a follow-up interview with parents to clarify whether or not specific behaviors are due to ADHD symptoms or ASD-related social impairments. Scores from the ADHD rating scales may need modification due to co-morbid ASD-associated factors. Parents seeking out assessments should ideally find a clinician experienced in the evaluation of both ASD and ADHD. Yerys said:

“Until we’re able to develop and validate a new rating scale that takes symptoms of autism into account, parents who are concerned should seek out clinicians who are conducting evaluations for ADHD and are also taking into account the possibility of autism.”

Why is This Study Important?

Evaluation of the ADHD Rating Scale in Youth with Autism highlights the uses and limitations of current tools and tests used to determine the diagnosis of ADHD in children. The process used to confirm observations in this study showed “unsatisfactory fits for one-, two- and three-factor models. There are several items that are deemed to be “cross-loading on multiple factors.”

Parents, educators, physicians and the medical community want to know how to accurately assess for ADHD or Autism. Research, such as in this study, underscores the possibility that the testing and diagnostic tools currently being used may have some restrictions for use and may need further refinement. A broader approach that involves observations from parents and educators will be needed to balance testing results.

A significant consideration is the need for more accurate testing using the ADHD rating scale and potentially other tests used to determine potential diagnosis of ADHD or other conditions that share similar behaviors with autism. Research findings may spur a new version of such diagnostic tools that can be more accurately applied to those with autism, ASD or related conditions. Improved treatment options may result from such a review and improve the lives of children with ADHD and/or autism.


Lisa DiFalco is a leading writer for wellness and education. She has helped manage cases directly at halfway houses before extensive careers in education and wellness. She is passionate about vital issues and supports community improvement efforts.

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