Over the past 15 years, the Infant Sibling Study has followed younger siblings of children with ASD, ADHD or typical development, with the goal of understanding the very earliest signs of these conditions. The ultimate goal of our research is to develop better methods for early detection of ASD, ADHD, and other childhood disorders, enabling earlier treatment.

In our study, we monitor attention skills, communication, social interest, motor activity, play behaviors, and academic achievement using a variety of methods including eye tracking, interactive tasks between the child and an examiner, standardized testing and parent interviews. At age 3, we are able to make diagnostic determinations for conditions that are usually apparent in the preschool age range (ASD, speech-language delay, etc.) with follow up evaluations between 6 and 13 years of age to examine later-appearing challenges, such as ADHD, learning disabilities, anxiety and mood disorders. We then determine how performance on tasks during infancy relate to later diagnostic outcomes. In a second study, we are currently testing the effectiveness of a video based early symptom detection tool completed by parents online. For both studies, we plan to conduct school-age follow-up assessments on over 300 of our enrollees.

What We’ve Learned

Here are some of the findings generated by the Infant Sibling Study research thus far:

  • The chances that a younger sibling of a child with autism will develop autism themselves is much higher than was originally thought, around 20%.
  • Very few infants show signs of autism before their first birthday, and symptoms usually develop between 12 and 18 months of age.
  • Some of the earliest appearing signs of ASD are not responding to name consistently, being more interested in objects than in interacting with people, and unusual use of objects, such as staring at them for prolonged periods, rotating them, or spinning them.
  • Accurate and stable diagnoses of autism can be made as early as 18 months of age.
  • The average age of diagnosis of children in our study is over two years earlier than the national average, allowing many families to access intervention services much earlier than is typically possible.
  • 30-40% of siblings of children with autism, who don’t develop autism themselves, show some behavioral, social, learning, or language challenges by the time they reach elementary school. ADHD is one of the most common of these difficulties seen in siblings of children with autism.

Study Participation

We are not currently enrolling new participants in the Infant Sibling Study. However, if you are pregnant or have a new baby and are interested in participating in similar research please contact the study listed below for details of participation and enrollment information.

Early Risk Study
Annie Chuang

If you are a previous participant in the Infant Sibling Study, your child is now 6 or older, and you’d like to come in for a school-age assessment, please contact us at 916-703-0297 or ahill@ucdavis.edu