About a third of children who have autism also have symptoms of attention deficit hyperactivity disorder, according to a study released Wednesday.
According to researchers at the Baltimore-based Kennedy Krieger Institute, which studies autism, the two disorders may be somehow linked.
"We are increasingly seeing that these two disorders co-occur and a greater understanding of how they relate to each other could ultimately improve outcomes and quality of life for this subset of children," Rebecca Landa, author of the study, said in a statement. The study was published in Autism: The International Journal and Practice.
Experts have long thought the two disorders might be linked, but previous studies have looked at patients who were already exhibiting symptoms of at least one of the disorders, leading to a potential selection bias. Landa's study followed 162 infants and toddlers before they were diagnosed through their eighth birthday. Of the 63 children who were diagnosed with autism, 18 (29 percent) also had "clinically significant" symptoms of ADHD.