It is a popular misconception that there is a growing autism epidemic in the US based in part on the changing prevalence numbers reported by the CDC. But given that the CDC is monitoring a sample of those most likely to develop autism one cannot make the claim that there is an epidemic. To the contrary, it is still unclear how many autistic people there are. The most accurate conclusion that can be drawn about the size of the population of autistic individuals using the changing CDC prevalence data is that more of the children most likely to have a developmental disorder at the ADDM sites are being diagnosed and receiving treatment.
So what can the CDC prevalence numbers tell us if they can’t be generalized to the whole population? Plenty. First, we see that race and ethnicity influences identifying ASD and also IQ placement. Second, while it is established in the scientific literature that ASD can be diagnosed as early as 12 months of age it is more commonly identified at 53 months. This suggests that something is causing a delay in diagnosis. Third, boys are still more often diagnosed than girls. Fourth, despite developmental concerns being noted for a number of the children seen at the monitoring sites these concerns did not always generate a comprehensive evaluation for the child in question.
What can parents take away from this discussion of CDC prevalence numbers? Take a second critical look at those making claims about there being an epidemic of autism because, frankly, the numbers available to us do not support such claims. If you as a parent have concerns about your child’s developmental progress push for a comprehensive evaluation of your child. Don’t be put off or take a wait and see approach.