The number of U.S. children estimated to have autism could decline as a result of new criteria to diagnose the condition, a new study suggests.
The findings show that 81 percent of children in the study diagnosed with autism under the old criteria would still be classified as having the condition under the new criteria, which were released last year in the new edition of the psychiatric handbook called the DSM-5.
Before the release of the DSM-5, some people were concerned that the new criteria would exclude some children who previously would have been diagnosed with autism, leaving these children without access to educational services available to children with autism.
The new findings should be reassuring to parents, said Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven and Alexandra Cohen Children's Medical Center of New York, who was not involved in the study.
"The overwhelming majority of children" who met the old criteria will continue to meet the new ones, Adesman told LiveScience.
In addition, it is likely that many children who fall short of a diagnosis of autism under the new DSM-5 criteria will qualify for services under a different psychiatric diagnosis, Adesman said. [The 10 Most Controversial Psychiatric Disorders]
According to Autism Speaks, an advocacy organization that funds autism research, no one previously diagnosed with an autism spectrum disorder (including Asperger's syndrome) will "lose" their diagnosis. "If you have a diagnosis for ASD, you have a diagnosis of ASD for your life and should be entitled to appropriate interventions for the rest of your life," the organization says on their website.
More stringent criteria?
The new study reviewed information from 8-year-olds living in 14 areas of the United States in 2006 and 2008. The estimated prevalence of autism in 2008 under the old criteria was 11.3 cases per 1,000 people in the population, but under the new criteria, the prevalence dropped to 10 cases per 1,000 people, the study found.
Autism spectrum disorders are developmental disabilities that can cause language delays, impaired social and communication skills, and repetitive behaviors. Over the years, the criteria used to diagnose autism have been revised several times.
In some ways, the new DSM-5 criteria for autism may be more stringent than the previous criteria, said study researcher Matthew Maenner, of the Centers for Disease Control and Prevention. For example, the minimum number of symptoms a person needs to have to be diagnosed with autism using the old criteria was two, but now, the minimum number is five, Maenner said.
However, in other ways, the new criteria are more flexible, Maenner said. For example, they allow doctors to consider past behaviors, rather than just current behaviors.
Still on the rise
Diagnoses of autism have risen in recent years — a trend not likely to be reversed by the adoption of new criteria, the researchers said.
Maenner noted that most of the children in the study who met the old criteria for autism, but failed to meet DSM-5 criteria, were off by only one symptom. (They had four symptoms instead of the necessary five.)
Many doctors are aware that a diagnosis of autism will qualify children for services, and it's possible that some doctors could be motivated to add more symptoms for children who are very close to meeting the diagnosis, Maenner said.
Because of the change in criteria, it will be challenging to compare newer estimates of autism prevalence to older ones, Maenner said. The new study "is a step we can take to begin to understand how to put those numbers in context," Maenner said.
The study is published today (Jan. 22) in the journal JAMA Psychiatry.