LOS ANGELES, Dec 12 — New US research has found that children whose older siblings have autism spectrum disorder (ASD) or attention-deficit/hyperactivity disorder (ADHD) are also at an increased risk for both disorders.
Led by researchers at the Department of Psychiatry and Behavioural Sciences and University of California, Davis, the new study looked at the medical records of 730 younger siblings of children with ADHD, 158 younger siblings of children with ASD, and 14,287 younger siblings of children with no diagnosis of either condition to investigate the risk for later-born siblings of children with either disorder.
The findings, published online in the journal JAMA Pediatrics, showed that later-born children whose siblings had ASD also had a 30 times higher risk of ASD, as well as a 3.7 times higher risk of ADHD, compared to later-born siblings of children without either condition.
Later-born children whose sibling had ADHD had a 13 times higher risk of being diagnosed with ADHD and a 4.4 times higher risk of ASD, compared to later-born siblings of non-diagnosed children.
With a worldwide prevalence of 5 per cent, ADHD is the most common childhood behavioral disorder. Symptoms include difficulty focusing, non-stop talking or blurting things out, hyperactivity and/or impulsivity which can interfere with a child’s development and academic performance.
Individuals with ASD experience a different set of symptoms, including challenges with social interaction and communication, unusual interests, or repetitive behaviours such as hand flapping or lining up objects.
However, both conditions are thought to share some genetic risk factors, a theory supported by the findings of the new study.
“We’ve known for a long time that younger siblings of children with autism are at higher-than-average risk for autism, but the field didn’t have adequate data to tell whether they were at increased risk for ADHD,” said lead author Meghan Miller. “Despite the fact that autism and ADHD appear very different in their descriptions, this work highlights the overlapping risk; younger siblings of children with ASD are at elevated risk of both ADHD and autism, and younger siblings of children with ADHD are at elevated risk not only for ADHD, but also for autism.”
The findings are significant as being able to diagnose ASD and ADHD earlier could improve both treatment and quality of life for those affected, with the researchers suggesting that families who already have a child diagnosed with ASD or ADHD should look out for symptoms of both conditions in younger siblings. — AFP-Relaxnews
