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Starting next year, clinicians worldwide may be using a new, streamlined set of criteria to diagnose autism.
The criteria are part of a highly anticipated update to the “International Classification of Diseases,” a diagnostic manual produced by the World Health Organization (WHO). The latest draft of the manual, dubbed ICD-11, collapses autism, Asperger syndrome and pervasive developmental disorder-not otherwise specified (PDD-NOS) into a single diagnosis of ‘autism spectrum disorder.’
“I think that this is good news,” says Catherine Lord, founding director of the Center for Autism and the Developing Brain at New York-Presbyterian Hospital. Lord was in the working group for the DSM-5 but was not involved in the ICD update. “It will make life simpler for people making diagnoses.”
The ICD-11 is scheduled to roll out in May 2018. The changes seem unlikely to provoke the controversy that accompanied the DSM-5 draft prior to its release. Some researchers worried at the time that people classified as having Asperger syndrome or PDD-NOS would lose access to services. Those concerns seem to have waned, and experts say that they don’t expect a similar reaction to the ICD-11.
“I’d be very surprised if there would be a battle,” says David Skuse, professor of behavioral and brain sciences at University College London, who is on the ICD-11 draft committee. “DSM-5 was conceptually correct and ICD-11 is following a similar view.”
Autism features outlined in the ICD-11 fall into the same two categories as those in the DSM-5: difficulties in initiating and sustaining social communication and social interaction, and restricted interests and repetitive behaviors. Previous versions of each manual included a third category for language problems.
Both of the new manuals allow clinicians to diagnose autism alongside other conditions, such as anxiety or attention deficit hyperactivity disorder; previous versions instructed clinicians to choose one of these diagnoses.
But there are notable differences between the two manuals, too. The ICD-11 provides detailed guidelines for distinguishing between autism with and without intellectual disability. The DSM-5, by contrast, simply acknowledges that autism and intellectual disability can co-occur.
Both the DSM-5 and ICD-11 subsume childhood disintegrative disorder, a regressive condition that surfaces in late childhood, into the autism spectrum, despite its distinct features. The DSM-5 does not include regression as a criterion for an autism diagnosis, however, whereas the ICD-11 lists “loss of previously acquired skills” as a feature on which doctors can base a diagnosis.
“[ICD-11] is taking some of the better parts of DSM without falling into the same pitfalls,” says Fred Volkmar, professor of child psychiatry, pediatrics and psychology at the Yale Child Study Center, who was a vocal critic of the DSM-5.
Unlike the DSM-5, the ICD-11 does not stipulate that a person must have a certain number or combination of features to meet the threshold for autism. Instead, it lists various defining features and lets a clinician decide whether a person meets the bar.
“The flexibility allows clinicians to make the diagnosis upon the clinical judgment and common sense, as long as you follow the concepts in the guidelines,” says Michael B. First, professor of clinical psychiatry at Columbia University, who serves as an editorial consultant to WHO.
Typical children might pick up a banana and use it as a phone, but many children with autism do not show this sort of ‘symbolic play,’ which is among the criteria for autism in the ICD-10.
But the way children play varies across cultures. The ICD-11 puts less emphasis on type of play and focuses more on whether children follow or impose strict rules while playing — a behavior that can show up in any culture. An insistence on rules and on imposing those rules on others could be a sign of inflexible thinking, which is common among people with autism.
(The DSM-5 also moves away from symbolic play, but does include some play-based criteria as “difficulties sharing imaginative play or in making friends; to absence of interest in peers.”)
The new manual is intended to embrace criteria that translate across cultures.
“What we are trying to do with ICD-11 is to create a set of criteria that are so broad that they could be applied anywhere in the world,” says Skuse.
Like the DSM-5, the new draft emphasizes the importance of testing for unusual sensory sensitivities, which are common among people with autism. It also alerts clinicians to the fact that some people on the spectrum try to mask their autism features.
“Many adults report using conversational strategies and coping mechanisms to mask their difficulties in pubic, but suffer from the stress of maintaining a socially acceptable facade,” Skuse says. “This is particularly true for girls.”
A draft version of the ICD-11 is available online with registration and is open for comment.