Siblings of children with autism: are they at higher risk of also developing autism?

Here at Research the Headlines we have written regularly about the use of inaccurate sensationalist headlines to attract the readers attention regardless of its validity. Well a headline has come out in the press that is so sensationalist I am left wondering if the author has made a huge misinterpretation or were indeed striving to be sensationalist!

The study looked at the frequency with which siblings of children with autism were likely to themselves develop autism or other behavioural problems.  The research group lead by Sally Ozonoff used a prospective longitudinal design, whereby they followed and assessed the behaviour of 294 high-risk infants and 196 low-risk infants every 6 months, from 6 months of age to 3 years old. The researchers found that, of the high-risk group, 17% developed autism and another 28% were classified as non-typically developing at 3 years of age. These differences between the low and high risk groups were evident on multiple measures from 12 months of age.

The Daily Mail ran with a headline “HALF of the siblings of autistic children develop abnormally – but the other half either develop the condition or have slower development”.  What? So you can see why I’m thinking is this another sensationalist headline or some sort of gross misinterpretation of the findings. This headline would suggest that 100% of siblings with autism develop autism or have atypical development! We know that’s not the case. The press release on this study very clearly describes the 28% and 17% findings and there is nothing in it to have led to the Daily Mail headline.

So what can we learn from this study (i.e. ignoring this media coverage!). The study shows that siblings of children with autism are at higher risk of developing autism or other behavioural problems than children with siblings who do not have autism. Importantly, the study also shows that such signs are not clearly evident at 6 months but are observable across multiple measures at 12 months old. This finding is particularly significant as early diagnosis can facilitate early interventions for the child.

S. Ozonoff, G. S. Young, A. Belding, M. Hill, A. Hill, T. Hutman, S. Johnson, M. Miller, S. J. Rogers, A. J. Schwichtenberg, M. Steinfeld, & A. -M. Iosif, (2014). The Broader Autism Phenotype in Infancy: When Does It Emerge? Journal of the American Academy of Child & Adolescent Psychiatry vol 53, pp 398-407. DOI: 10.1016/j.jaac.2013.12.020