The U.S. Centers for Disease Control and Prevention (CDC) estimate that one in every 88 children has been diagnosed with autism spectrum disorder (ASD).
Those figures, however, use data from 2008, when ASD was diagnosed under the Diagnostic and Statistical Manual of Mental Disorders’ revised fourth edition (DSM-IV-TR). A study released Wednesday suggests that using new criteria from the fifth edition (DSM-5), that number is now closer to one in 100 children.
The study, published in the American Medical Association’s journal Psychiatry, shows that the symptoms required for an autism diagnosis have changed. As many as 28 percent of children currently diagnosed with autism may no longer qualify if they don’t have intellectual disabilities.
According to the National Institute of Neurological Disorders and Stroke, ASD is a group of neurodevelopmental disorders characterized by social impairments, difficulty communicating, and restricted, repetitive patterns of behavior. Autistic disorder, commonly referred to as autism, is the most severe form of ASD.
Diagnosing Autism With New Criteria
Released in May, the new DSM-5 changed the way mental health disorders are classified. The official diagnostic handbook of the American Psychiatric Association affects what’s covered by insurance plans and other important factors for those seeking therapy.
Changing the diagnostic criteria for a disorder is nothing new. The definition of autism was revised in 1987 and again in 1994. The DSM-IV-TR was released in 2000, and the criteria for diagnosing autism remained unchanged until the release of the DSM-5 last year.
The DSM-5 does not distinguish among subtypes of ASD—such as autistic and Asperger's Syndrome—and recognizes only two domains of impairment: social communication and restricted, repetitive patterns of behavior, interests, or activities. Now, for a child to be diagnosed as autistic, all three requirements in the social communication domain must be met. Under the DSM-IV-TR, only two were required.
To examine the effects of the guideline changes, a research team led by Matthew J. Maenner of the National Center on Birth Defects and Developmental Disabilities at CDC evaluated 6,577 8-year-old children in the Autism and Developmental Disabilities Monitoring Network, which draws data from 14 monitoring sites in the U.S.
Changing Autism Rates Across States
Researchers found that 96.1 percent of children in the network met the diagnostic criteria for autism under the DSM-IV-TR, but the percentage who met the DSM-5 standards ranged from 68.8 percent in Florida to 95.6 percent in Utah.
Even without the new DSM changes, researchers found that rates of autism were lower than previously reported. Researchers say that after evaluating the cases, about 7.4 out of every 1,000 children should have been diagnosed with autism, instead of 11.3 per 1,000 children, at it was in 2008.
Researchers concluded that this newfound information will have a much more profound effect on prevalence estimates for autism than it would on a patient’s eligibility for services.
“Autism spectrum disorder prevalence estimates will likely be lower under DSM-5 than under DSM-IV-TR diagnostic criteria, although this effect could be tempered by future adaptation of diagnostic practices and documentation of behaviors to fit the new criteria,” the authors concluded.