Sunday, May 22, 2011

Autism spectrum disorders: increasing prevalence or diagnosis shift?

A physician reader of AFP submitted the following post.


The recent editorial “The Changing Prevalence of the Autism Spectrum Disorders” in the March 1st issue discusses many of the challenges surrounding autism and the apparent increase in prevalence of this diagnosis. Having spent 30 years as the medical director of a private residential facility for children with developmental disabilities, I have some additional observations to add.

Many years ago, the most common diagnosis at our school was “mental retardation.” Subsequently, this diagnosis fell out of favor and was replaced by “static encephalopathy.” I seldom see these admitting diagnoses any more from referring neurologists and developmental pediatricians. Instead, some children are labeled as having “global developmental delay,” but virtually all children are also diagnosed as being on the autism spectrum. I am convinced that a great deal of what we are seeing in this population is a shift in diagnosis rather than a real change in prevalence.

In the past, children with known genetic disorders such as Down syndrome, Fragile X syndrome, or tuberous sclerosis were excluded from the diagnosis of autism. Now, autism is usually the second or third diagnosis. In my mind, this is like diagnosing a patient with a broken leg as having a gait disturbance. Although it may be technically true, it adds little to the diagnosis. Children with developmental disabilities typically have difficulties with social interaction, communication and behavior. Although some of these behaviors may be similar to those of children with autism, I believe that the supplemental diagnosis is not helpful.

A wide variety of services, including medical assistance, early intervention, and wraparound services, are available to children with autism which are not available to the same children if the diagnosis is mental retardation. I have often encountered parents who insist on the diagnosis of autism for their child even if I believe that the child does not fit in the autistic spectrum, because they want their children to have access to the benefits and services that accompany this diagnosis.

Many children who were previously diagnosed as having minimal brain dysfunction or being emotionally disturbed (or even just considered “odd”) are now rightfully recognized as belonging in the high functioning end of the autistic spectrum. Once again, I believe much of the increase in prevalence we are seeing is diagnosis shift.

Richard G. Fried, MD
The Camphill Special School
Glenmoore, PA