Increasing Incidence of Autism Spectrum Disorders: Fact or Fiction
Contributed by Dr. Cathy Pratt, Director

Each year, the IRCA reports on the incidence of autism spectrum disorders in public schools in Indiana. Ten years ago, commonly accepted incidence rates ranged from 2 to 5 individuals per 10,000. Today, the Centers for Disease Control believe that the incidence may be as great as 1 in 166 for those diagnosed with autism, Asperger’s syndrome, and other pervasive developmental disorders.

So, if the projected incidence rates are accurate, what does this mean for Indiana? Based on the latest census data from 2001, Indiana is home to an estimated 6,114,745 citizens. At an estimated rate of 1 in 166, there are potentially 36,688 individuals with a diagnosis on the autism spectrum. Remember these numbers are projected and only estimate the real occurrence of autism spectrum disorders in Indiana. No database exists of the actual numbers of people with autism spectrum disorders.

Another example of this increase is the 2003-2004 Child Count Data collected by the Indiana Department of Education, Division of Exceptional Learners. The number of students enrolled in Indiana’s public schools, during the 2003-2004 school year, was 1,010,688. The number of students between the ages of 3 and 21 identified with an autism spectrum disorder during this same period of time was 5,473. This is even more significant when one considers that over 800 more students are being served under this disability category then in 2002-2003.Using these numbers, approximately .005% or 5 in 1,000 students in Indiana have a diagnosis of an autism spectrum disorder. Based on the child count data, each year there is over a 22% increase in the number of students served under the category of autism spectrum disorder.

While there is a general belief and awareness that autism spectrum disorders are on the rise, it is unclear why. Some believe that more children are being identified because the medical community and other professionals have a better understanding of autism spectrum disorders, and because the definition of autism has been expanded to encompass more individuals. Others believe that the increase is real and are advocating for research to investigate the potential causes of autism. Regardless, more Indiana citizens are being diagnosed with autism, pervasive developmental disorders, or Asperser’s syndrome.

This increase has the potential to have a major impact on the local and state economy of Indiana. Many of those being diagnosed are still young and are being served in early intervention and elementary school programs. School districts are beginning to see the

wave of those diagnosed hit middle and high school. In a few short years, these individuals will be eligible for and in need of adult services. Whether we believe the growth is fact or fiction, the reality is that we have an increasing number of individuals with complex support needs who will soon be in need of adult services. Let’s make sure we are ready.