A study in Spain found that around 3% of schoolchildren exhibit symptoms of both autism and attention-deficit/hyperactivity disorder (ADHD). Approximately 0.5% of children could be diagnosed with both disorders. About 33% of autistic children and 31% of those with autism symptoms that do not reach the diagnostic threshold also had ADHD. Additionally, 10% of children with ADHD also had autism. The paper was published in Autism Research.