Keywords:
Intellectual disability, autism, developmental disorder, prevalence, trends
Abstract:
Estimates of the prevalence of intellectual disability or autism spectrum disorder may vary depending on the methodology, geographical location, and sources of ascertainment. The National Disability Insurance Scheme in Australia was introduced progressively from 2016 to provide individualized funding for eligible people with a significant and permanent disability.
Background
Estimates of the prevalence of intellectual disability or autism spectrum disorder (ASD) may vary depending on the methodology and sources of ascertainment. The National Disability Insurance Scheme (NDIS) in Australia was introduced progressively from 2016 and the IDEA database now receives information on people with intellectual disability or autism from this source as well as from the WA Departments of Communities and Education.
What we did
Using the numbers of individuals recorded in the IDEA database in 2020 with either intellectual disability or autism, we calculated the current prevalence of each diagnosis. We then compared this with our previous estimates using births to 2010.
What we found
Whilst the prevalence of intellectual disability had increased from 17.1 to 22.5/1000 livebirths, the prevalence of autism had increased more sharply from 5.1 to 20.7/1000 livebirths. We noted an increased prevalence of ASD in Aboriginal children under 10 years although overall the prevalence in the Aboriginal population is about two-thirds that of non-Aboriginal individuals.
What it means
Our results show clear increases in rates of ASD over the past two decades, with an acceleration since the introduction of the NDIS. The need for diagnoses to access disability supports via the NDIS could be contributing to these increasing incidence rates of ASD within Australia. In light of these findings the challenge continues to be that of delivering high quality disability support that achieves outcomes for people with disability and their families in a sustainable way.