Early signs of autism not evident in children under six months

Researchers have found that the behavioural signs of autism appear later in the first year of life for most children with the condition.

The study's lead author Sally Ozonoff, a professor of psychiatry and behavioral sciences and a researcher with the UC Davis MIND Institute, found that the nascent symptoms of the condition are not present at 6 months, but emerge gradually and only become apparent during the latter part of the first year of life.

Ozonoff said: "Contrary to what we used to think, the behavioral signs of autism appear later in the first year of life for most children with autism. 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 6 and 12 months of age."

The research discovered that 86% of the infants who developed autism showed declines in social communication that were outside the range for typical development.

The study found: "After six months the autism spectrum disorder group showed a rapid decline in eye contact, social smiling, and examiner-rated social responsiveness."

Ozonoff said: "Until now, research has relied on asking parents when their child reached developmental milestones. 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.

She continued: "This study also found that the loss of skills continues into the second and third year of life. So it may not be adequate, as the American Academy of Pediatrics currently suggests, that providers screen for autism twice before the end of the second year. Autism has a slow, gradual onset of symptoms, rather than a very abrupt loss of skills."

"Screening may need to continue into the third year of life, since symptom emergence takes place over a long time. If a child starts exhibiting a declining trajectory and a sustained reduction in social communication we want to refer them into therapy, especially if they are at risk," Ozonoff said, "even before we might be able to make a definitive diagnosis."

The study is due to appear in the Journal of the American Academy of Child & Adolescent Psychiatry.