FRIDAY, Jan. 20 (HealthDay News) -- The number of people
diagnosed with autism will likely decrease if a new definition of
the disorder is adopted by mental health experts later this
Doctors aren't sure what the implications of the changes will
be, but they agree there will be an impact on the lives of people
with autism and the professionals who treat them. The changes could
affect the number of people eligible for health, educational and
But some experts contend that a clearer definition of autism is
needed because the current definition is too hazy and may have
contributed to an exaggerated number of people with the
"This is not an academic exercise," said Geraldine Dawson, the chief science officer for Autism Speaks, an advocacy organization, and a professor of psychiatry at the University of North Carolina at Chapel Hill. "These changes in the diagnostic criteria will have a real impact on people's lives and we have to be very careful as we begin to implement the new criteria that we monitor how this is affecting people's ability to obtain services."
The new definition would create just one diagnostic category --
autism spectrum disorder -- that would replace the three subtypes
that are used now. Those subtypes are Asperger syndrome, autism
spectrum disorder and pervasive developmental disorder-not
otherwise specified (PDD-NOS).
The revised definition of autism is being drafted by a panel of
experts appointed by the American Psychiatric Association. The new
definition will be part of the psychiatric association's Diagnostic
and Statistical Manual of Mental Disorders (DSM), the "bible" for
psychiatric diagnoses. The manual is currently in its fourth
edition, which was released in 1994, but the much-anticipated fifth
edition should be final by the end of this year.
Although the new definition of autism isn't final, it's "very
likely," Dawson said. "They [the expert panel] are extremely close,
so any changes at this point will probably be relatively
Estimated rates of autism in the United States have surged since
the 1980s, with some recent figures running as high as one in every
110 children. Some experts say there has been a bona fide increase
in the number of cases, while others contend that the lack of
clear-cut diagnostic guidelines is to blame.
Autism is a complex neurodevelopment disorder with typical
symptoms that include difficulty communicating with others, the
inability to form social relationships, and repetitive movements
such as rocking and twirling, or even self-abusive behavior such as
biting or head-banging, according to the U.S. National Institute of
Neurological Disorders and Stroke.
The cause of autism remains unknown.
Under the new definition of autism, Asperger syndrome, which
generally describes a higher functioning individual, would be
eliminated, as would PDD-NOS, a sort of catch-all category.
A study presented Thursday at a meeting of the Icelandic Medical
Association estimated that less than half (45 percent) of 372
children and adults diagnosed with autism in a 1993 paper would
qualify under the new criteria,
The New York Times reported.
A previous study came to a similar conclusion, Dawson said, with
both papers appearing to identify fewer people with autism.
"In particular, they're identifying fewer individuals who are higher functioning, for example, Asperger [syndrome patients]," she said.
From a scientific point of view, the changes in diagnostic
criteria make sense, Dawson said. The subcategories don't have any
meaning in terms of etiology, or what causes autism. Nor do they
necessarily differentiate recommended treatments, she added.
And clinicians don't always agree on diagnoses for particular
But science aside, Dawson said, "We have to keep in mind the
real-world implications. In particular, we have to be very careful
that through this process that we're not excluding people from
receiving services that they need and deserve."
Dr. Andrew Adesman, chief of developmental and behavioral
pediatrics at the Steven and Alexandra Cohen Children's Medical
Center of New York in New Hyde Park, said the new definition is
"trying to lend some greater precision" to the diagnosis of
But, so far, experts aren't even sure if the recent estimates of
autism's prevalence are correct, he said. "There are differences of
opinion," he added.
"Only time will tell what kind of impact this will have," Adesman said.
The U.S. National Institute of Neurological Disorders and Stroke
has more on
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