Children with autism spectrum disorder may be mistakenly diagnosed with attention-deficit hyperactivity disorder (ADHD) because they have autism-related social impairments rather than problems with attention.
The researchers noted that a well-established screening tool used to assess children for ADHD may be less accurate when a child has autism.
"One of our best current screening measures for ADHD may be over-diagnosing ADHD in children with autism," said study leader Benjamin Yerys, a researcher in the Centre for Autism Research at Children's Hospital of Philadelphia (CHOP) in the US.
"This is important because medications that work for ADHD may be less effective for a child on the autism spectrum," Yerys noted.
The researchers suggested that the tool they analysed, the ADHD Rating Scale Fourth Edition (ADHD-RS-IV), while well-validated in assessing ADHD in a general population of children, may overestimate ADHD in children with autism spectrum.
One complicating factor is comorbidity -- an estimated 30 percent or more of children with ASD also have ADHD, said the study published in the Journal of Autism and Developmental Disorders.
The study team concluded that the tool needs to be refined to better identify the correct disorder, and that clinicians should supplement the screening tool with careful clinical interviews.