In 2008, based on a sample of 8 year olds, the Centers for Disease Control (CDC) reported that the prevalence of autism had risen to 1 in 88 in American children. By 2010, using a similar sample, it was announced that the incidence had climbed to 1 in 68. Based on these latest numbers, 1 in 42 boys and 1 in 189 girls are being diagnosed with an autism spectrum disorder (ASD). Three years ago in a national telephone survey of 100,000 families, the incidence was projected at 1 in 50. The CDC just released new incidence numbers based on input from 11 states. The incidence remains stable at 1 in 68. (Note: Different data collection methods will often yield differing results.)
So, what does this mean for Indiana? Since no database currently exists in Indiana with the actual number of people on the autism spectrum, either statewide or by county, the only real figure comes from the December 1 child count data collected by the Indiana Department of Education, Department of Special Education. These data are collected from all public school districts across Indiana. The chart at the end of this article illustrates the increasing incidence of ASD since 1999.
According to the child count data from December 2012, the number of children served under the diagnostic category of ASD was 13,020; and with the December 2013 data, the number had grown to 13,675. By December 2014, this number had grown to 14,179 and by December 2015 there was an increase from the previous year of 1,112 for a total of 15,291. Last year’s child count data (December 2016) was 15,815 for an increase of 524 students ages 3-21. This year’s child count data (December 2017) for children ages 3-21 was 16356 for an increase of 541.
The number of students enrolled in Indiana’s public and non-public schools during the 2017-2018 school year is 1,139,822. Using this data and the child count data from December 2017, approximately 14.35 per 1,000 students in Indiana have a diagnosis of ASD. Last year’s identification rate was 1 in 72. This year’s identification rate is 1 in 69.69. The child count data does not include children who are not on special education service plans, are home schooled or are in non-public schools. All who have either an IEP or special education service plan are counted.
The other reality is that many of these children come with complex issues and support needs. According to the CDC, ASD commonly co-occurs with other developmental, psychiatric, neurologic, chromosomal, and genetic diagnoses. The co-occurrence of one or more non-ASD developmental diagnoses is 83% and maybe as high as 90%. The co-occurrence of one or more psychiatric diagnoses is 10%. The potential impact on our schools and other service delivery systems continues to be tremendous. Education services and an array of community supports are needed to successfully support children and adults on the autism spectrum.
Pratt, C. (2018). Increasing incidence of autism spectrum disorders in Indiana. The Reporter, 22(11). Retrieved from https://www.iidc.indiana.edu/pages/incidence-of-autism-spectrum-disorders-in-indiana
Indiana Resource Center for Autism
Indiana Institute on Disability and Community
Indiana University, Bloomington
1905 N Range Road, Bloomington, IN 47408-9801