California Autism Prevalence Trends from 1931 to 2014 and Comparison to National ASD Data from IDEA and ADDM

J Autism Dev Disord. 2018 Dec;48(12):4103-4117. doi: 10.1007/s10803-018-3670-2.


Time trends in U.S. autism prevalence from three ongoing datasets [Individuals with Disabilities Education Act, Autism and Developmental Disabilities Monitoring Network, and California Department of Developmental Services (CDDS)] are calculated using two different methods: (1) constant-age tracking of 8 year-olds and (2) age-resolved snapshots. The data are consistent across methods in showing a strong upward trend over time. The prevalence of autism in the CDDS dataset, the longest of the three data records, increased from 0.001% in the cohort born in 1931 to 1.2% among 5 year-olds born in 2012. This increase began around ~ 1940 at a rate that has gradually accelerated over time, including notable change points around birth years 1980, 1990 and, most recently, 2007.

Keywords: ADDM; ASD prevalence; Autism spectrum disorder; Autistic disorder; CDDS; IDEA; Time trends.

MeSH terms

  • Autistic Disorder / epidemiology*
  • California / epidemiology
  • Child
  • Developmental Disabilities / epidemiology*
  • Female
  • Humans
  • Male
  • Population Surveillance / methods
  • Prevalence