As experts behind a forthcoming update of the Diagnostic and Statistical Manual of Mental Disorders look to revise psychiatry’s definition of “mental retardation” their efforts are becoming unexpectedly contentious.

Under a draft that’s currently open for public comment, experts working with the American Psychiatric Association are proposing that the name of the diagnosis be changed to “intellectual developmental disorder.”

What’s more, they’re looking to give more discretion to clinicians by putting less emphasis on IQ. While people qualifying for the diagnosis would still be required to score at least two standard deviations below average on such assessments, there would no longer be a bright-line IQ requirement of 70 or under.

The changes are bringing significant backlash from two of the most established organizations in the country advocating for those with intellectual disabilities — the American Association on Intellectual and Developmental Disabilities and The Arc.

Both groups object to the name change arguing that the psychiatric profession should follow the federal government and most other entities in adopting the term “intellectual disability.” The groups say that using a different phrase in clinical settings would do nothing more than confuse people.

“I think there’s a great deal of shared concern on this disorder and the way it’s being conceptualized in the DSM-5,” said Margaret Nygren, executive director of the American Association on Intellectual and Developmental Disabilities.

Beyond the name, Nygren says the proposal diverges widely from the existing diagnosis criteria currently endorsed by the American Psychiatric Association, which has always been closely aligned with a definition produced by her own group.

Nygren says the lack of specificity in the proposed diagnosis with regard to testing for IQ and adaptive functioning is troubling. She also believes that there should be a finite age by which symptoms of the disorder manifest. Currently the DSM requires that individuals meet the criteria for “mental retardation” prior to age 18, but the draft changes would ease that requirement indicating that symptoms must originate “during the developmental period.”

“This decision will have a great impact on our community,” said Peter Berns, CEO of The Arc, which plans to submit comments to the psychiatric association expressing concerns similar to those of Nygren’s group.

The proposed changes remain a work in progress, according to James Harris, a professor of psychiatry and pediatrics at the Johns Hopkins University School of Medicine who is a member of the American Psychiatric Association work group responsible for updating the “mental retardation” diagnosis.

However, Harris said one aspect driving the committee’s proposal is a desire to align its criteria with an upcoming revision of the International Classification of Diseases, or ICD, a guide to diseases and disorders published by the World Health Organization.

ICD plans to use “intellectual developmental disorder” in it’s eleventh version, which is expected in 2015. Despite significant debate within the DSM committee, Harris says they determined that the term favored by ICD more accurately describes the condition for clinical purposes as compared to “intellectual disability” which puts an emphasis on functioning level.

What’s more, though IQ tests would still be required under the proposed changes, the medical groups are looking to move away from a reliance on scores alone to determine a diagnosis.

“There is only one diagnosis that’s based on a test,” Harris says, referring to the current standard for the “mental retardation” label. “All the other diagnoses are based on people. We want to focus on the person, not the number.”

Changes to the “mental retardation” diagnosis are not the only ones yielding controversy. Many disability advocates have also expressed concerns about proposed alterations to the definition of autism after some studies suggested that many currently diagnosed with the disorder may no longer qualify under the new criteria.

The proposed changes call for folding autistic disorder, Asperger’s syndrome, childhood disintegrative disorder and pervasive developmental disorder, not otherwise specified under one umbrella diagnosis of “autism spectrum disorders,” with diagnosticians indicating a level of severity associated with an individual’s condition.

The American Psychiatric Association is accepting public comment through June 15 on proposed changes for the fifth edition of the DSM. Then, work groups tasked with revising the psychiatric manual are expected to make final recommendations to the organization’s board in December. Publication of the manual is anticipated in May 2013.