A proposed revision to the diagnostic criteria for intellectual disability is prompting concerns about underdiagnosis and a loss of services and legal protections for people with the condition.

The American Psychiatric Association, or APA, is considering altering the entry for intellectual disability in the Diagnostic and Statistical Manual of Mental Disorders-5, or DSM-5. Often called the bible of psychiatry, psychiatrists, researchers, insurers and others rely on the manual to determine what symptoms are worthy of a diagnosis.

At issue is a connection between two of the three criteria for diagnosing intellectual disability. The three criteria are: deficits in intellect, deficits in adaptive functioning or daily life skills, and onset during childhood.

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One sentence, which was included when the DSM-5 was released in 2013, appears to require that adaptive function deficits be caused by intellectual deficits, said Margaret Nygren, executive director and CEO of the American Association on Intellectual and Developmental Disabilities, or AAIDD.

It reads in part, “the deficits in adaptive functioning must be directly related to the intellectual impairments.” In 2018, AAIDD requested that the sentence be struck.

Instead, APA has proposed replacing it with language that says in part “deficits in adaptive functioning are a consequence of intellectual deficits.”

“That’s really inconsistent with how the condition has been understood in our field,” Nygren said. “There’s no scholarly evidence backing this up, there’s no research, there’s no clinical evidence.”

The APA allows a process for making revisions to the DSM on a rolling basis, rather than waiting for periodic updates to the entire manual. The organization is accepting comments on the proposed intellectual disability revision until Aug. 14. A date has not been determined for when a revision of the section could be released.

“At the conclusion of the public comment period, all of the submitted comments will be reviewed and a decision will be made as to whether modification of the proposed change is needed,” Dr. Paul Appelbaum, a psychiatrist and chair of the DSM Steering Committee, said in a statement.

The committee has not said why it has proposed drawing a connection between the two diagnostic criteria.

Nygren said experts have agreed that intellect and adaptive behavior are separate concepts and it’s impossible to distinguish which aspects of adaptive behavior are the result of IQ, educational opportunities or mental health issues.

“It would be really hard to diagnose anybody because you can’t ever prove that deficits in adaptive function are caused by your IQ,” she said. “You’re clearly going to be moving toward under identifying people with intellectual disability and it’s not fair to them because they won’t be getting services they need to have the best possible quality of life.”

Nygren said the current DSM-5 language has already been used in a legal case where the state of Texas sought to execute a man with intellectual disability. The state argued that his adaptive functions were likely caused by a lack of learning opportunities rather than being directly related to his intellectual function, and so therefore, he did not have an intellectual disability.

In February, the U.S. Supreme Court in Moore v. Texas ruled against the state finding that he does have an intellectual disability and set aside a lower court decision allowing his execution.

The concerns raised by AAIDD have flagged the issue to other intellectual disability groups.

Philip Davidson, a New York researcher and president of the International Association for the Scientific Study of Intellectual and Developmental Disabilities, said he was not aware of the proposal until AAIDD released comments.

“We’re going to take a very careful look at this,” Davidson said.

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