A new version of the Diagnostic and Statistical Manual of Mental Disorders released this month includes changes to the definitions of both autism and intellectual disability that experts say will further clarify the diagnoses.

The American Psychiatric Association issued the updated manual, which mental health care practitioners, researchers and insurers rely on for decision-making in diagnosing and treating patients, following a three-year process to reflect scientific advances since the fifth edition was published in 2013.

More than 200 advisers reviewed proposals submitted online by researchers. While there have been occasional corrections to the fifth edition, the latest revision known as the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision — or DSM-5-TR — marks a significant number of updates including the addition of a new entry, prolonged grief disorder.

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The manual’s entry for intellectual disability will now be labeled “intellectual developmental disorder (intellectual disability)” to more closely align with the World Health Organization’s disease classification system which uses “disorders of intellectual development.”

Intellectual developmental disorder will also include revised language to communicate that while the diagnosis “should not be bound narrowly to the 65-75 IQ score range, the diagnosis would not be appropriate for those with substantially higher IQ scores.”

The changes “strengthen the clarity of the entry on intellectual disability,” said Margaret Nygren, executive director and CEO of the American Association on Intellectual and Developmental Disabilities.

The DSM entry now also aligns with the association’s manual of diagnostic criteria, Nygren said.

“Consistency between these manuals is very important because even small differences between them can create confusion and could negatively impact eligibility criteria for essential supports,” she said.

The changes to the entry for autism spectrum disorder are generally considered minor tweaks compared to the differences in the fifth edition released nine years ago. That edition consolidated four labels — autistic disorder, Asperger’s syndrome, childhood disintegrative disorder and pervasive developmental disorder, not otherwise specified — under the umbrella diagnosis of autism spectrum disorder.

One change allows clinicians to describe related behaviors that don’t rise to the level of a separately diagnosable condition, such as self-injury. Instead of “associated with another neurodevelopmental, mental or behavioral disorder,” it now reads, “associated with a neurodevelopmental, mental or behavioral problem.”

A second change is aimed at clearing up potential misunderstandings of a diagnostic criterion. The fifth edition required an autism diagnosis to include “persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following: deficits in social-emotional reciprocity, in nonverbal communicative behaviors used for social interaction, and in developing, maintaining and understanding relationships.”

The latest revision changes that paragraph to read “as manifested by all of the following” to eliminate confusion over the inclusion of one, two or three of the deficits.

Autism advocates said they don’t expect the changes to have a significant impact on diagnoses.

“It’s a small but helpful clarifying change intended to emphasize the serious and disabling nature of (autism spectrum disorder),” said Jill Escher, president of the National Council on Severe Autism.

The council is among the groups advocating for a carveout for severe autism in future editions of the diagnostic manual, saying the current umbrella-style entry remains overly broad.

“We know from our conversations with some members of the DSM-5 work group that they had concerns about the watering-down of autism, which by definition is a significant impairment of basic functional abilities, and not a mere ‘difference,’ ‘neurotype,’ ‘learning style’ or ‘trait,'” Escher said.

The changes should not affect current diagnoses or insurance coverage for families, according to the American Psychiatric Association.

But Zoe Gross of the Autistic Self Advocacy Network said she worries that the group’s manual could be moving toward a more narrow definition to address a societal perception of over-diagnosis.

“Changing the DSM in the future for the purpose of reducing the amount of diagnoses would do a disservice to autistic people who may no longer be able to access diagnosis or services,” particularly for girls, adults and people of color, Gross said. “If the APA is considering substantial changes to the way autism is diagnosed, autistic people must be involved in that process from the start.”

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