ASD, ADHD more Common in Young Siblings of Children with the Conditions

Researchers found that younger siblings of children with autism spectrum disorder were 30 times more likely to be diagnosed with ASD and almost four times more likely to be diagnosed with attention-deficit/hyperactivity disorder than children whose older siblings did not have ASD or ADHD.

The findings in JAMA Pediatrics also showed children whose older siblings had ADHD were 13 times more likely to be diagnosed with ADHD and more than four times more likely to be diagnosed with ASD.