Symptoms of Autism by Age One

A study by researchers at UC Davis has found that symptoms of autism begin appearing by age one. The five-year study compared the behavior of siblings of children diagnosed with autism to the behavior of babies developing normally. Researchers counted instances of communicative and social behavior, e.g., smiling, babbling, and eye contact.

Their results indicate that by 12 months development between the two groups had diverged significantly. Whereas children who were developing normally showed increasing levels of intentional social and communicative behavior, infants later diagnosed with autism displayed decreasing levels of social behavior.

See the announcement here. The full paper is (behind a paywall):
S. Ozonoff et al., “A Prospective Study of the Emergence of Early Behavioral Signs of Autims,” Journal of the American Academy of Child & Adolescent Psychiatry 49, no. 3 (2010): 256–66.