Estimated Autism Spectrum Disorder Prevalence Unchanged

According to a CDC report published April 1, 2016, an estimated 1 in 68 (14.6 per 1,000) school-aged children have been identified with autism spectrum disorder (ASD). This report shows essentially no change in ASD prevalence, the proportion of school aged-children with ASD, from the previous report released in 2014. However, it is too soon to know whether ASD prevalence in the United States might be starting to stabilize. The CDC will continue tracking ASD prevalence to better understand changes over time.


The data come from the CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network – a tracking system that provides estimates of the prevalence and characteristics of ASD among 8-year-old children in 11 communities within Arizona, Arkansas, Colorado, Georgia, Maryland, Missouri, New Jersey, North Carolina, South Carolina, Utah, and Wisconsin. The data in the latest report are for 2012 while the data in the previous 2014 report were from 2010.


Although the average ASD prevalence of the 11 ADDM Network sites combined did not change between 2010 and 2012, ASD prevalence still varied widely between the 11 communities. Differences were seen by geographic region and between sites with different access to data resources. “What we know for sure is that there are many children living with autism who need services and support, now and as they grow into adolescence and adulthood,” said Stuart K. Shapira, MD, PhD, chief medical officer for the CDC’s National Center on Birth Defects and Developmental Disabilities.


The new report also underscores where efforts and resources can be directed to better support children and families with ASD. Black and Hispanic children continue to be less likely to be identified with ASD than white children. In addition, black and Hispanic children receive developmental evaluations later than white children. “Targeted strategies are needed to identify and address barriers in order to lower the age at which black and Hispanic children are evaluated, diagnosed, and connected to the services they need,” said Daisy Christensen, PhD, a CDC epidemiologist and lead author of the ADDM Network report.


The report also shows that, overall, less than half (43%) of children identified with ASD receive developmental evaluations by age three. This suggests that many children may not be getting identified as early as they could be. Progress needs to be made to reach the Healthy People 2020 goal of increasing to 47% the proportion of children with ASD having a first evaluation by age three. “The most powerful tool we have right now to make a difference in the lives of children with ASD is early identification,” said Dr. Shapira. “Parents, childcare professionals and doctors can monitor each child’s development and act right away on any developmental concerns. It’s important to remember that children can be connected to services even before an official diagnosis is made.”


The American Academy of Pediatrics recommends that pediatric health care providers administer two ASD screenings, at ages 18 and 24 months, using a valid and reliable screening tool. Children whose screening results are concerning should subsequently receive a comprehensive developmental evaluation from a general or developmental pediatrician, child neurologist, child psychiatrist, or child psychologist, which can be obtained privately or through the Part C (ages 0–<3 years) or Part B (ages 3–21 years) programs of the Individuals with Disabilities Education Act supported by each state. To support and measure progress in early identification, the Healthy People 2020 initiative includes a goal to increase the percentage of children with ASD who receive their first comprehensive evaluation by age 36 months by 10%, from the baseline of 42.7% in 2006 to the goal of 47.0% in 2020. ADDM Network ASD surveillance data for children aged eight years are used to evaluate progress toward this goal.


No intervention has been shown to reduce the prevalence of ASD. However, early treatment might maximize the ability of children to function and participate in their community. Initiation of school-based services prior to formal school entry might help to facilitate optimal educational progress. Continued efforts should be made to promote early identification of all children with ASD so that interventions can be initiated at the youngest age possible.


ASD is a developmental disability characterized by social and communication impairments and by restricted interests and repetitive behaviors. The first studies of the prevalence of autism were published in the 1960s and 1970s, when autism was thought to be a very severe condition, usually accompanied by intellectual disability. These studies reported the prevalence to be approximately four to five cases per 10,000 children. Autism was first distinguished as a unique clinical diagnosis by the American Psychiatric Association with the publication in 1980 of the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), which provided diagnostic criteria for infantile autism and pervasive developmental disorder. Since that time, autism has become recognized as a spectrum of behavioral characteristics, which results in varying degrees of functional limitations. In 1994, the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) introduced revised diagnostic criteria and five subtypes of autism, including autistic disorder, Asperger disorder, pervasive developmental disorder–not otherwise specified (PDD-NOS), childhood disintegrative disorder, and Rett’s disorder. The first three subtypes comprise ASD, whereas the latter two conditions belong to the wider category of pervasive developmental disorders. The fifth edition of DSM, which was published in 2013, redefined ASD as a single disorder, along with other changes in the diagnostic classification of ASD. For this report, the evaluations contained in children’s records were conducted no later than 2012, and therefore DSM-IV-TR diagnostic criteria were used in the ASD surveillance case definition to estimate ASD prevalence and characteristics.


The ADDM Network estimated prevalence across multiple U.S. sites every two years during 2000–2012. The most recent prevalence estimate from the ADDM Network for children aged eight years was 14.6 per 1,000 children compared with 14.7 per 1,000 children in 2010, 11.3 in 2008, 9.0 in 2006, 6.6 in 2002, and 6.7 in 2000.


The CDC’s “Learn the Signs. Act Early” program provides parents, childcare professionals, and healthcare providers free resources, in English and Spanish, for monitoring children’s development. The program offers parent-friendly, research-based milestone checklists for children as young as two months of age. The program also offers information about what to do if there is a developmental concern and whom to contact for assistance.


The ADDM Network will continue to monitor the prevalence and characteristics of ASD among children aged eight years living in selected sites across the United States. Recommendations from the ADDM Network include enhancing strategies to (1) lower the age of first evaluation of ASD by community providers in accordance with the Healthy People 2020 goal that children with ASD are evaluated by age 36 months and begin receiving community-based support and services by age 48 months; (2) reduce disparities by race/ethnicity in identified ASD prevalence, the age of first comprehensive evaluation, and presence of a previous ASD diagnosis or classification; and (3) assess the effect on ASD prevalence of the revised ASD diagnostic criteria published in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.


See the CDC Announcement


See the CDC Report


See also Medical Law Perspectives, April 2016 Report: A Spectrum of Risks Related to Autism: Liability Issues and Litigation