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.
A previous study published in 2011 suggested that there may be some "genetic overlap" between genes that cause both ADHD and autism.
The reason is both people with ADHD and Autism have weak executive functioning in the brain, some people with autism have it more than others... I am an adult with autism with no adhd symptoms, but my son however has the ADHD diagnosis. It's just a label to explain some more difficulties... not exactly a seperate disorder.