Social influence playing role in surging autism diagnoses

http://www.eurekalert.org/pub_releases/2010-04/uocp-ssi040810.php

Social influence plays a substantial role in the surging number of autism diagnoses, according to a study published in the American Journal of Sociology.

The study, by researchers from the Institute for Social and Economic Research and Policy at Columbia University, found that children living near a child who has been previously diagnosed with autism have a much higher chance of being diagnosed themselves in the following year. The increased likelihood of being diagnosed is not due to environmental factors or contagious agents, the study found. Rather, it is due mainly to parents learning about autism from other parents who have a child diagnosed with the disorder.

----- (skipping)

The study also showed the proximity effect to be strongest among children on the milder side of the autism spectrum. That is also consistent with a social influence explanation, Dr. Bearman says. "Parents of severely disabled kids are more likely to recognize the disorder without needing input from social contacts," he said. "So we would expect to see a weaker proximity effect there, and that's exactly what we found."

The data set used in the study allowed the researchers to judge just how strong the influence effect is compared to other factors that may be driving the epidemic. For example, previous studies have found a link between autism and parents' ages. Parents today are having children later in life, and that could be causing autism cases to increase. Other studies have found that parents' education plays a role as well. Better educated parents may be more likely to obtain a diagnosis for their children.

The Columbia team found that each of these factors plays a role in the epidemic, but that the social influence phenomenon was the strongest. The researchers estimate that the proximity effect explains about 16 percent of the recent increases in autism diagnoses. Put another way, if no child lived within 500 meters of a child with autism, there would be a 16 percent reduction in autism diagnoses. That effect was stronger than the other factors tested. The mother's age explained about 11 percent of the increase. The mother's education accounted for 9 percent.

======================================================

The researchers are not saying that social influence affects whether or not a child has autism. What it affects is whether a child is diagnosed as being autistic.

..