Autism Declines By One-Third, But Only Due To New Definition
Physicians News Digest
February 26, 2014

A new study finds that Autism may decline by as much as one-third. But the reduction is not due to a cure — it’s due to a definition. Researchers found that a change in diagnosis guidelines for autism spectrum disorder (ASD) may significantly reduce the number of children being identified with the neurological disorder.

“This study raises a concern that a medical provider diagnosing a child under the new guidelines won’t find the child to be on the autism spectrum, when the same child under the old criteria might have been diagnosed with ASD,” says study author Kristine M. Kulage, MA, MPH, director of the Office of Scholarship and Research Development at Columbia University School of Nursing.

The Diagnostic and Statistical Manual of Mental Disorders (DSM) — which has been referred to as the “bible of psychiatry” — recently completed its first update in 17 years. Some of the revisions from DSM-4 to DSM-5 were poorly received in the mental health community, as experts charged the changes could do more harm than good. Many criticisms were leveled specifically at the changes in autism guidelines.

The DSM-4 included three distinct subgroups under the broad definition of ASD: autistic disorder (AD), Asperger’s disorder, and pervasive development disorder-not otherwise specified (PDD-NOS). The revised manual, DSM-5, eliminates these subgroups, instead establishing a more limited range of criteria for a diagnosis of ASD that is designed to encompass individuals who previously would have fallen into one of the subgroups.

Under the DSM-5 guidelines, there was a statistically significant decrease in AD diagnosis of 22 percent, compared to DSM-4, according to the study published in the Journal of Autism and Developmental Disorders. There was also a statistically significant decrease of 70 percent in diagnosis of PDD-NOS. While diagnosis of Asperger’s also declined under DSM-5, the reduction was not statistically significant.

“We are potentially going to lose diagnosis and treatment for some of the most vulnerable kids who have developmental delays,” says Kulage. “In many instances, children require a diagnosis of ASD to receive medical benefits, educational support and social services.”

According to the Centers for Disease Control and Prevention (CDC), approximately 1 in 88 kids in the U.S. have autism — a ten-fold increase in the last 40 years. The new definitions may help to decrease that number, but the problems of identifying the underlying causes and potential cures remain.

A separate study published in JAMA Psychiatry had similar results as it found 20 percent of children formerly categorized with ASD did not meet the DSM-5 criteria. However, many of those children were very close to meeting the new guidelines and were missing only one of the necessary symptoms. Children were more likely to meet DSM-5 criteria if they had a history of developmental regression or an intellectual disability.