Autistic Children Over-Diagnosed With ADHD, Study Suggests
By guest blogger Julie M. Depenbrock
Photo courtesy of Getty Images
A new study conducted by the Center for Autism Research at the Children's Hospital of Philadelphia has found that children with autism may be over-diagnosed with ADHD.
Teachers and parents who use the screening tool, which assesses children for attention deficit hyperactivity disorder (ADHD), may mistake autism-related social impairments for attention problems, according to the study. This, in turn, could affect the services and treatments that autistic children receive.
"The worst thing, to me, is sending a family down a bad path," said study leader Benjamin E. Yerys, a clinical psychologist at Children's Hospital. "Part of getting a diagnosis is knowing what treatments might be helpful for your child."
This is important because treatments for ADHD have been less effective in children with autism, Yerys said. For example, methylphenidate, a drug better known by its trade names Concerta and Ritalin, has only been effective for 49 percent of autistic patients, according to a 2012 study from NIH. Eighteen percent saw significant adverse side effects, compared with 1 percent to 2 percent of methylphenidate users without autism, Yerys said.
"If the tool isn't working properly, it might set people up to think certain treatments may be helpful, and maybe they're not," he added. "It has a very important downstream effect."
Screening results are often used to recommend school services as well as potential medications.
In 18 questions, the screener known as the ADHD Rating Scale Fourth Edition (ADHD-RS-IV) asks parents and teachers to numerically rate a child's behaviors.
Half of the questions are focused on inattention, the other half on hyperactivity.
Thomas J. Power, who co-authored the study, developed ADHD-RS-IV in the 1990s. A fifth edition of the screening tool was released in March. ADHD-RS-V features a new section on where symptoms might impair a child—at home or at school. It also includes a change to a question on hyperactivity, which tends to manifest itself as a sort of restlessness as children get older.
The study, which was submitted one month prior to the publication of the new screener, used the fourth edition.
"We wanted to evaluate one of the most common screeners that is used in screening and diagnosing ADHD in kids with autism," Yerys said. "It's only been in the last year or so that we've gotten approval from our diagnostic manual to make a diagnosis of both autism and ADHD in the same child."
The simultaneous presence—or comorbidity—of not only autism and ADHD, but also autism and anxiety, can complicate the diagnosis.
One question on the screener asks: "Does the child respond when spoken to directly?"
A simple yes or no fails to indicate whether a child lacks social skills (autism) or is inattentive (ADHD).
"Some kids seem to have a lot more fear and perceived threat in social situations. And that's maybe not something specific to autism," Yerys said. "It's this other condition that's overlapping with autism."
How do you get a more accurate diagnosis for your child?
That falls on the doctor, Yerys said.
"We have to be smarter about when a parent says 'yes' to some of these questions. What is really behind that?" he asked. "The clinician has to do some follow-up."
The study, which also involved researchers from the Perelman School of Medicine at the University of Pennsylvania and Baylor University, was published last month in the Journal of Autism and Developmental Disorders. You can find the study here.
The participants were 386 children, ages 7-17—all of whom have autism, but no intellectual disability. The researchers found that some of the items in the screening tools they evaluated flagged elevated levels of ADHD-like symptoms in the study sample.