CDC's Autism and Developmental Disabilities Monitoring Network

The Autism and Developmental Disabilities Monitoring (ADDM) Network is a group of programs funded by CDC to determine the prevalence of the autism spectrum disorders in United States communities. Its goals are:

• To obtain as complete a count as possible of the number of children with an autism spectrum disorder each project area.

• To report comparable, population-based autism spectrum disorder prevalence estimates from different sites and to determine if these rates are changing over time.

• To study whether autism is more common in some groups of children than in others.

• To provide data to characterize the autism spectrum disorder population.

The ADDM Network's first two autism spectrum disorder prevalence reports were released in the February 9, 2007, issue of the Morbidity and Mortality Weekly Report Surveillance Summaries. These data found between 1 in 100 and 1 in 300 children with an average of 1 in 150 8-year-old children in multiple areas of the United States had an autism spectrum disorder. All children in the studies were eight-years-old because previous research has shown that most children with an autism spectrum disorder have been identified by this age for services.

What did the ADDM network results released on February 9, 2007, tell us about the prevalence of autism spectrum disorders in the United States?

For decades, the best estimate for the prevalence of autism was four to five per 10,000 children. More recent studies from multiple countries using current diagnostic criteria conducted with different methods have indicated that there is a range of autism spectrum disorder prevalence between 1 in 500 children and 1 in 166 children. These data released in 2007 from CDC/ADDM Network studies provide information on the occurrence of autism spectrum disorders in fourteen communities in the United States. Six ADDM sites evaluated the prevalence of autism spectrum disorders in children who were eight years old in 2000 (born in 1992). An additional eight sites determined autism spectrum disorder prevalence for children who were eight in 2002 (born in 1994). The ADDM Network determines autism spectrum disorder prevalence through the review of health and education records in collaboration with state health departments, diagnostic facilities, and school systems in the specified areas.

Results from CDC’s ADDM network showed:

• The average autism spectrum disorder prevalence among states participating in the project was 6.7 per 1,000 children in 2000 (6 sites) and 6.6 per 1,000 in 2002 (14 sites), or approximately 1in 150 children.

• The average finding of 6.6 and 6.7 per 1,000 eight-year-olds translates to approximately one in 150 children in these communities.

• Most sites identified between 5.2—7.6 per 1,000 8-year-old children with an autism spectrum disorder in 2000 and 2002.

• There was some variation with autism spectrum disorder prevalence. It was significantly lower in 1 site (3.3 in AL) and higher in 1 site (10.6 in NJ).

• Prevalence was stable from 2000 to 2002 in 4 of the 6 sites that participated in both surveillance years, but increased slightly in Georgia and significantly in West Virginia, indicating the need for ongoing monitoring of prevalence over time.

Additional reports will update prevalence information over time. As this is the first multi-site report from the ADDM Network, these data provide an important standard (or baseline) with which to compare future prevalence data.

• ADDM Surveillance Years 2000 and 2002 Press Release

• Fact Sheet

• ADDM MMWR SS February 9, 2007

What sites/states participate as part of the ADDM Network?

ADDM Current Phase (2006-2010)
CDC currently funds a total of 10 ADDM sites and participates as the 11th. Sites in the following states participate as part of the ADDM network:
Alabama, Arizona, Colorado, Florida, Georgia/CDC, Maryland, Missouri, North Carolina, Pennsylvania, South Carolina, Wisconsin.

ADDM Phase 1 (2000-2006)
ADDM's first phase included funding for up to 16 sites.  These sites include the current phase list above plus Arkansas, California, New Jersey, Utah, and West Virginia.

Why do we need to know the prevalence of autism spectrum disorders?

Families, public agencies, and some private agencies bear the responsibility of paying for costly services involved in educating and treating symptoms associated with autism spectrum disorders. Accurate reporting of autism spectrum disorder prevalence can help people plan for the resources needed such as therapies, trained teachers, diagnosticians, health care providers, and related service professionals.

A recent study¹ indicated that the economic costs associated with autism are approximately $35 billion dollars per year; not to mention the untold challenges that families face in understanding their family member with autism spectrum disorder. Planning for housing and job training also require accurate numbers over time.

Accurate reporting of autism spectrum disorders over time and from different communities can also help to answer the question, is their variability in autism spectrum disorders in different areas of the country or in different groups of people? Precise reporting of autism spectrum disorders leads to better planning by service providers, and helps to provide justification for limited research dollars from public and private sectors. Precise reporting of autism spectrum disorders also can lead to greater awareness, encourage commitment by service providers and researchers, and help lead the way to more effective intervention and prevention.

For More Information

• CDC's Autism and Developmental Disabilities Monitoring (ADDM) Network
• Autism Research: CDC's Study to Explore Early Development
• CDC's Autism Information Center
• CDC's Learn the Signs. Act Early. Campaign
• International Autism Epidemiology Network* CDC has joined with Autism Speaks to form the International Autism Epidemiology Network (IAEN) to improve collaboration in understanding the populations affected by autism spectrum disorder around the world.

¹ Ganz, M.L. The costs of autism. In: Moldin SO, Rubenstein JLR, editors. Understanding autism: From basic neuroscience to treatment, 1st Edition) Boca Raton (FL): CRC Press; 2006 p. 475-502.