Is autism contagious?

by Benison O'Reilly on Friday, May 14th, 2010

In the introduction to the Australian Autism Handbook I write that having Joe has made me ‘a kinder and wiser person’, one who no longer ’sweats on the small stuff’.  Two years later I can confirm that still rings true.  I remain more tolerant of life’s vicissitudes and my fellow human beings and their failings. Not much upsets me.

However, there is one aspect of life where I remain less tolerant and that concerns my children.  If anyone seriously slights one of my boys I feel it keenly. This particularly applies if anyone slights Joe.

Anyway, without giving too much away, there was once a woman of my acquaintance — a woman with neurotypical children— who made it clear that— despite my gestures of friendship— she wanted as little to do with Joe and me as possible.  Was it me? Or was it Joe? I’m not sure. I can rationalise the former, but the latter…not so easily.

I once said to my husband, ‘Perhaps she thinks autism is contagious’.

Thus, I was surprised to find that a recent study suggests that it is.

Okay, I’m bending the truth a bit.  But hopefully I’ve caught your attention.

What the study, by researchers from Columbia University, did find is 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.

However, the researchers do not believe this is because autism is contagious. Nor do they think it’s due to an environmental agent.  They believe it is because parents are learning about autism from other parents who have a child on the spectrum; they are being educated about symptoms, and the process of obtaining a diagnosis and treatment, from people who have already been through the process with their own child.

In the study, entitled Social Influence and the Autism Epidemic, researchers looked at data on over 304,000 children born in California between 1997 and 2003. They found that children who live within 250 metres of a child with autism have a 42% higher chance of being diagnosed with an ASD in the following year compared with children who do not live near a child with autism. Children who live between 250 metres and 500 metres from a child with autism were 22% more likely to be diagnosed. As we would predict, the study showed the proximity effect to be strongest amongst children with high functioning autism, the sort of kids whose symptoms and behaviours might have been explained away as ‘oddness’ in earlier times.

The researchers eliminated competing explanations, such as environmental toxins or viral transmission through a series of statistical tests. They also considered other social factors that could be driving the autism ‘epidemic’, such as maternal age and education standards (some studies have found that older parents are more likely to have a child with an ASD, whilst others suggest that better educated parents are more likely to obtain a diagnosis for their child). Whilst the Columbia University team found that each of these social factors appears to play a role in the rising prevalence of autism, the so-called ‘social influence’ phenomenon exerted the most powerful effect.

The researchers conclude:

One does not “catch” autism from someone else, yet a social diffusion process contributes significantly to the increased prevalence of autism.

Looks like we might have found another piece in intriguing puzzle of why autism diagnoses are on the increase.

The paper, published in the American Journal of Sociology, is available free to download on the link below.

Ka‐Yuet Liu, Marissa King, and Peter S. Bearman. Social influence and the autism epidemic.

American Journal of Sociology 2010 115:5, 1387-1434

http://www.journals.uchicago.edu/doi/full/10.1086/651448

Or read more commentary on the study at Science Daily:

www.sciencedaily.com/releases/2010/04/100408161017.htm

Tags: autism, prevalence, research