Autism Signs Not Present at Birth but Emerge by First Birthday


Researchers from the University of California-Davis MIND Institute have found that the earliest symptoms of autism, such as lack of eye contact, smiling, and communicative babbling, are not present during the first six months of an infant’s life, but become apparent between six months to one year.

Publishing their work in the March issue of the Journal of the American Academy of Child and Adolescent Psychiatry, lead author Sally Ozonoff said, “Most babies are born looking relatively normal in terms of their social abilities but then, through a process of gradual decline in social responsiveness, the symptoms of autism begin to emerge between six and 12 months of age.”

The researchers conducted their study of 50 children over a five year period by counting each instance of infant social behavioral cues during examinations until the children were age 3 using diagnostic tools such as the Autism Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview-Revised (ADI-R). Half of the babies were considered high risk for developing autism because they had a sibling with the disorder.


By the age of 12 months, it became apparent which children would ultimately be diagnosed with autism because intentional social and communicative behavior decreased dramatically. 86% of the children who developed autism showed declines in social communication, including a reduction in eye contact, social smiling, and social responsiveness.

“Until now, research has relied on asking parents when their child reached developmental milestones,” said Ozonoff. “But that can be really difficult to recall, and there is a phenomenon called the telescoping effect, where people usually say that they remember something happening more recently than when it occurred.”

The study also helped identify the most appropriate age to begin screening children for signs of autism. The American Academy of Pediatrics currently suggests that providers screen for autism twice before the end of the second year of age. “Screening may need to continue into the third year of life, since symptom emergence takes place over a long time,” says Ozonoff.

Autism Spectrum Disorder affects approximately 1 percent of children in the United States with onset occurring prior to age 3. Abnormal brain development, most likely beginning in the womb, is known to be fundamental to the behaviors that characterize autism – the deficits in social skills, communication, and repetitive and restricted behaviors.