A new study, published this week in JAMA Pediatrics, finds that younger siblings of children with autism spectrum disorder (ASD) or attention-deficit/hyperactivity disorder (ADHD) are at increased risk for both disorders.
The study, led by the Department of Psychiatry and Behavioral Sciences at the UC Davis MIND Institute, suggests that parents with children who have ASD or ADHD should closely watch younger siblings for signs of both conditions.
“Reliable recurrence risk estimates of diagnoses within the same disorder and across other disorders can aid screening and early-detection efforts,” say the study’s researchers.
“This study certainly underscores the importance of sibling monitoring to help identify brain disorders as early as possible and provides us with new information about the links between some of these disorders,” says Dr. Terry Hamlin, Associate Executive Director at The Center for Discovery. “It is also significant in helping us get a deeper understanding of the relationship between environmental and genetic components of ASD.” (TCFD is opening a new Research Center for Brain and Body Health in 2020 to build on its pioneering research and studies into a variety of complex conditions including ASD.)
The researchers found the odds of an ASD diagnosis were 30 times higher in younger siblings of children with ASD, and nearly 4 times higher for a diagnosis of ADHD. Children whose older sibling had ADHD, had a 13 times higher risk of being diagnosed with ADHD, as well as a 4.4 times higher risk of an ASD diagnosis.
ADHD is one of the most common neurodevelopmental disorders of childhood, according to the Centers for Disease Control and Prevention, and researchers believe it shares some genetic risk factors and biological influences with ASD.