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Baby Sibling Outcomes: Beyond Autism

Guest post by Daniel Messinger, PhD, professor of psychology and pediatrics at the University of Miami, and developmental psychologist Gregory Young, PhD, of the MIND Institute at the University of California, Davis. Both belong to Autism Speaks Baby Siblings Research Consortium.

Autism Speaks Baby Siblings Research Consortium (BSRC) was formed to advance international research on the development of young children who have an older brother or sister on the autism spectrum. Are these younger siblings at risk for autism or other problems? Our research is delivering answers.

In 2011, we looked at 664 baby sibs of children with autism. At age 3, around one in five had been diagnosed with an autism spectrum disorder (ASD). Boy siblings had a higher risk, as did younger kids with more than one older sibling on the spectrum.

Still, we wondered about the other baby sibs – the four out of five who did not develop autism. We knew that some of these children struggled with language and social skills. Some appeared to have difficulty expressing their wants. Others seemed to express wants inappropriately, creating socially awkward situations. But these were just observations. Would they stand up to rigorous testing?

To find out, we studied more than 500 baby sibs who did not have an ASD at age 3. We compared their development with that of a group of children from families not affected by autism. This week, the Journal of the American Academy of Child and Adolescent Psychiatry published our findings. [Editor's note: See our related news story here.]

As a group, the baby sibs in this study showed more autism symptoms than did the children in the comparison group. Their language and problem-solving skills weren’t as high. On average, these differences between the baby sibs and the comparison group were relatively small. However, it seemed likely that some baby sibs had more serious challenges while others were just fine.

To get a clearer picture, we used a statistical program that analyzed the children’s autism symptom scores and their language and other cognitive skills. The program classified the children into five groups with distinct similarities. In doing so, we gained important insights into the possible outcomes of baby sibs who do not end up with an ASD.

Two of the five groups looked entirely typical. Children in both groups had few autism symptoms. In one group, they also showed average language and cognitive skills. In the other they showed above-average skills. These two groups comprised nearly two thirds (65 percent) of the baby sibs. Good news!

Another group of kids had no problems with language or cognitive skills, but showed relatively high levels of autism symptoms that were still short of a diagnosis. One in seven baby sibs fell into this group. But so did one in ten children from low risk families. This reminds us that many children, not just baby sibs, struggle with some autism-related symptoms. 

Children in the last two groups likewise faced challenges. In one group, children scored “normal” on a scale of autism symptoms, but with low language and cognitive skills. The other group had higher levels of autism symptoms and low-average language and cognitive skills. Significantly more baby sibs fell into these two groups (1 in 4), than did the children from families not affected by autism (1 in 14). We also saw a lot of boys in these groups. About three of four baby sibs in these two groups were boys.

Our take-away message is that autism is not always all or nothing.

A significant number of baby sibs who don’t develop ASD will nonetheless have related challenges. As such, they may need early intervention services. This group includes children who don’t readily engage in back-and-forth play with others or who fail to point to express interest in activities or objects around them. These children may have trouble understanding others or the appropriate ways to use crayons and other toys.

Even though four out of five baby sibs are not headed for an ASD diagnosis, some will face real difficulties. As such, their development bears watching by parents and professionals.

The good news is that we have developmentally appropriate interventions for these young children. Many baby sibs need our help, whether or not they end up with an ASD diagnosis.

We want to sincerely thank the Autism Speaks community for supporting this important work.

Editor’s note: For more about Autism Speaks Baby Siblings Research Consortium, click here. Many of its researchers also participate in Autism Speaks Toddler Treatment Network. Autism Speaks Early Access to Care initiative seeks to close the gap in early intervention services for underserved communities in North America and abroad.