Are Too Many Kids With Autism Being Diagnosed With ADHD?

Benjamin Yerys, PhD


December 12, 2016

Editorial Collaboration

Medscape &

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Hi. I'm Benjamin Yerys, a child psychologist at The Children's Hospital of Philadelphia. Children with autism have a secondary diagnosis of attention-deficit/hyperactivity disorder (ADHD) anywhere from 30% to 50% of the time. This is a very high rate. We wanted to evaluate whether this was accurate and whether the tools we use in children with autism are valid, being that they were created for use in children with ADHD in the general community.

We evaluated the ADHD Rating Scale, one of the most common scales used in the field, in nearly 400 children with autism. Both parents and teachers completed the forms. We did a number of tests looking at the effectiveness or validity of the ADHD Rating Scale. It was effective on some measures, such as tracking symptoms across age. But it missed a very important benchmark, a procedure known as a "factor analysis." By failing the factor analysis, we see that children with autism are being rated high on certain question items, regardless of whether or not they really have attention problems. The scores are actually inflated, meaning that more children with autism will be rated as having a high risk for ADHD than is probably the case. The ADHD Rating Scale is not really capturing inattention or hyperactivity impulsivity the way that we think it should be.

This has significant clinical implications. For providers, it means that if parents are rating symptoms quite high and their child has a diagnosis of autism, you probably would want to do some follow-up interviewing with that family. You would want to know: Is the endorsement of symptoms by the parent or by the teacher really because the child has attention problems, or because they have social difficulties? One example is a [rating] question like, "Child does not listen when spoken to directly." The parent may say "yes" because the child has problems with paying attention. But the parent may also say "yes" because the child has problems with understanding how social interactions work so they are not understanding that when the parent is talking, they are talking to the child.

Clinicians need to ask additional questions to really try to pull that apart. A general pediatrician may want to make a referral for a child with autism to a specialist. If a parent has a question about autism versus ADHD, again, it may be very useful to have a specialist look at this rather than just using a screener like the ADHD Rating Scale or the Vanderbilt, which is commonly used in general practices and is built very similarly to the ADHD Rating Scale.

Our future goal for this research is to refine this measure so that we can measure ADHD symptoms and autism with more precision. By doing this, we will actually set ourselves up so that we can measure changes related to treatment much better than we do currently.

Thank you for paying attention to this video and for your interest in our work.