In July 2013, the American Psychiatric Association (APA) revised its criteria for autism spectrum disorders in what some call Psychiatry’s “Bible” — the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5). In a recent JAMA Psychiatry study, researchers suggest the stricter guidelines could change the number of people estimated to have a diagnosis of autism — a change that carries weight given that it could possibly exclude many children from access to services they might need.

According to older guidelines, if children met six of 12 criteria, they could fall under one of several different conditions: autistic disorder, childhood disintegrative disorder, pervasive developmental disorder (not otherwise specified), or Asperger's disorder. But the new guidelines combine all of these conditions under one name: autism spectrum disorder (ASD) and require children to meet stricter criteria. They must show two out of four types of repetitive patterns of behavior and three recognized deficits in social communication. The study says some experts suggest the DSM-5 criteria “require a higher threshold of symptoms.”

The authors of the study concluded that “Autism spectrum disorder prevalence estimates will likely be lower under DSM-5 than under DSM-IV-TR diagnostic criteria,” adding that translation of their hypotheses into reality depends on how individual doctors actually choose to make use of the new criteria when diagnosing children. Researchers had analyzed a database of about 6,577 8-year-old children diagnosed with an ASD by the old criteria. They found that if they applied the new guidelines to these children, 5,339 would have kept their diagnosis, leaving over 1,000 out. Most of these children missed the cut by only one additional criterion. The researchers point out that had the changes been in effect in 2008, the prevalence of the disorder in the United States would have been lower: one in 100 children, as opposed to the most recent estimate of one in 88.

But how might the stricter standards affect children who are missing one or two criteria but need services and attention not available to them? In other words, how might stricter words and categories exclude children who belong to neither category? Michael Rosanoff, associate director of public health research for Autism Speaks, a nonprofit advocacy group, says the change will affect children who are first seeing their doctors with symptoms. “The biggest concern is what may happen to individuals diagnosed for the first time, or re-evaluated using the DSM-5,” Rosanoff said. “A change in criteria does not necessarily mean there is a change in whether a person can benefit from services.”

Furthermore, Rosanoff points out that most of the children excluded from an autism spectrum disorder diagnosis under the new criteria may receive the new diagnosis of social communication disorder (SCD) instead, as one recent study published Thursday suggests. This could be a problem. “There are currently no treatment guidelines for SCD,” Rosanoff said. “ Until those guidelines are developed, Autism Speaks advocates that all who receive this diagnosis receive appropriate autism intervention services.”

Rosanoff adds that the changes from the DSM-IV TO DSM-5 will make it more difficult to keep track of ASD in the United States, since future numbers may not be comparable to past numbers. “We must not lose sight of the dramatic increase in autism prevalence over time and of the need to better understand what, in addition to changing diagnostic criteria, may be causing it,” he said.

Sources: Maenner M, Rice C, Arneson C, et al. Potential Impact of DSM-5 Criteria on Autism Spectrum Disorder Prevalence Estimates. JAMA Psychiatry. 2014.