Data from the Centers for Disease Control and Prevention (CDC) suggests that autism spectrum disorder (ASD) is becoming more commonly identified in children. According to a 2020 study of 11 surveillance sites in the CDC’s Autism and Developmental Disabilities Monitoring Network, one in 36 children (2.8%) were estimated to have autism spectrum disorder, up from one in 44 (2.3%) in 2018, and one in 150 (0.7%) children in 2000.
What is autism spectrum disorder?
The CDC defines ASD as “a developmental disability that can cause significant social, communication and behavioral challenges.” (ASD is caused by neurological differences, which can be caused by known genetic conditions along with other not-yet-identified factors — or most likely, a combination). Other influences might include older parents, a difficult birth, infections during pregnancy, and environmental impacts.
People with autism may learn, behave, and interact differently than others. Some are nonverbal and need assistance with daily living; others have advanced conversational abilities and live independently with little or no support. According to the CDC, ASD begins before the age of three and is generally lifelong, though symptoms may improve as people age.
There is no medical test for autism, and it can be difficult to diagnose. It’s not uncommon for people to receive diagnoses in adolescence or adulthood. The CDC cautions that the symptoms of ASD also appear in people without autism.
Prevalence of ASD over time
As identification methods have improved, autism spectrum disorder diagnoses have become more frequent in children, according to the CDC’s Autism and Developmental Disabilities Monitoring Network (ADDMN), which began researching autism in 2000. The latest ADDMN surveillance data — which only includes children from 11 sites, and is not necessarily representative of the entire United States —reports that 2.8% of monitored children were diagnosed with autism in 2020, compared to 1.5% in 2010, and 0.7% in 2000.
Autism spectrum disorder is more commonly identified in boys than girls. In 2020, 4.3% of 8-year-old boys were estimated to have autism, compared with 1.1% of girls of the same age.
Until 2010, autism was more prevalent among children of higher socioeconomic status. That trend has lessened in recent years, which the CDC interprets as caused by “improvements in more equitable identification of ASD, particularly for children in groups that have less access or face greater barriers in obtaining services.”
In 2020 the CDC estimated autism to be less prevalent among white children than Black, Hispanic, or Asian children for the first time. Past estimates showed ASD diagnoses were 50% higher in white children than Black or Hispanic children. That gap has narrowed in recent years, and the three categories were even in 2016 and 2018 estimates.
Autism rates may be increasing because more people are aware of the condition, screening has improved, and more people have access to services that are linked to identifying autism. That’s especially likely for children who are younger, nonwhite, and from lower-income families, according to the CDC.
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Children identified with ASD by 48 months
Early identification of autism spectrum disorder has improved in recent years, so more children receive ASD diagnoses at a younger age. Of all children born in 2016, 1.8% received an autism diagnosis or special education classification by the time they reached age four, compared with 1.1% of children born in 2012.
How did the pandemic impact diagnoses and treatment for autism?
The COVID-19 pandemic disrupted autism evaluations, causing fewer four-year-olds to be identified and treated for autism. The CDC says those delays “could have long-lasting effects,” and encourages communities to evaluate the impacts those delays had on children.
What actions do public health officials recommend for supporting children with ASD?
The Autism and Developmental Disabilities Monitoring Network says early screening and identification is one of the most important ways communities can better support children living with autism spectrum disorder. “The earlier that children are identiﬁed with ASD, the earlier they can access services and supports,” said its 2023 community report.
The Autism and Developmental Disabilities Monitoring (ADDM) Network is an active surveillance program that provides estimates of the prevalence of ASD among children aged 8 years. In 2020, there were 11 ADDM Network sites across the United States (Arizona, Arkansas, California, Georgia, Maryland, Minnesota, Missouri, New Jersey, Tennessee, Utah, and Wisconsin). To ascertain ASD among children aged 8 years, ADDM Network staff review and abstract developmental evaluations and records from community medical and educational service providers. A child met the case definition if their record documented 1) an ASD diagnostic statement in an evaluation, 2) a classification of ASD in special education, or 3) an ASD International Classification of Diseases (ICD) code.
The Children’s Health Act of 2000 authorized the CDC to create the ADDM Network to "track the number and characteristics of children with ASD and other developmental disabilities using CDC’s Metropolitan Atlanta Developmental Disabilities Surveillance Program (MADDSP) as a guide." The ADDM method is population-based and "reflect real-world community practices." CDC reports that it "will continue to monitor the number and characteristics of children with ASD over time, track progress in the early identification of ASD, and describe health and service needs of adolescents with ASD."