About a third of children diagnosed with autism also have symptoms of attention deficit hyperactivity disorder, a new study has found.
Researchers from Kennedy Krieger Institute, who conducted the study, also found that children with both disorders have more cognitive, developmental and social problems than children who have autism spectrum disorder.
"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," said Dr. Rebecca Landa, director of the Center for Autism and Related Disorders at Kennedy Krieger and senior author of the study. "The recent change to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to remove the prohibition of a dual diagnosis of autism and ADHD is an important step forward."
The study included 162 children between ages 4 and 8 years who were categorized into two groups based on their ASD diagnosis. Further, the ASD group was subdivided into those who had symptoms of ADHD based on the parents' report of the child's behavior.
Researchers found that 29 percent of the 63 children with ASD had symptoms of ADHD. Researchers said that children with these two conditions require a different treatment approach than children with one condition.
"We focused on young school-aged children because the earlier we can identify this subset of children, the earlier we can design specialized interventions," said Dr. Landa in a news release. "Tailored interventions may improve their outcomes, which tend to be significantly worse than those of peers with autism only."
The study is published in the journal Autism: The International Journal and Practice (Epub ahead of print).