NCPA - National Center for Policy Analysis


May 1, 2008

A new study from Oxford University seems to have confirmed the cause of the recent rise of autism as being a change in the diagnostic criteria.  It is unlikely that people now labeled autistic would, in the past, have been thought healthy, but is quite plausible they might have been given some other diagnosis, says Dr. Dorothy Bishop, head of the study.

Looking at 38 adults or teenagers who had, as children, been diagnosed as having what is known as developmental language disorder, rather than autism, the researchers found:

  • Almost a third of her volunteers looked, from the modern point of view, misclassified.
  • Eight fully met the modern criteria for autism.
  • A further four fell into what is known as the autistic spectrum, evincing signs of autism short of the full-blown syndrome.

What were particularly telling were the interviews with parents.  Earlier, similar work had explained the observations away as a change in symptoms with age, but the parents of Bishop's volunteers told stories of what are now regarded as autistic symptoms appearing in their children in their early years.  Although there is a risk of hindsight coloring such stories, many of them were so vivid that Bishop is convinced they are accurate.

Bishop is cautious and points out that finding one cause is not proof that others are not operating.  But it now looks unlikely that there are more autistic people around than there used to be.   It is just that it is now fashionable to acknowledge their existence.

Source: "Not More, Just Different," The Economist, April 10, 2008.

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