Diagnosing autism may get new criteria
The American Psychiatric Association is moving a step closer to overhauling the criteria for diagnosing autism after two just-completed field studies found the new definition won’t exclude patients who need treatment.
The change, to be included in a manual used by doctors, is designed to help them better identify the disorder by including several closely related disorders under the autism mantle, and by making symptoms more precise. Disease advocates have said they’re concerned the change may improperly reduce the number of children diagnosed, limiting access to health services.
One of the field trials showed a 1 percentage-point rise in diagnosis rates under the new criteria and the other showed a drop of 4 or 5 percentage points, said Darrel Regier, the association’s director of research. The trials were done in the last year at Baystate Medical Center in Springfield, Massachusetts, and Stanford University in Palo Alto, California.
“There was concern that by tightening the criteria we would drop the bottom out from people with previously diagnosed autism,” said Regier, who is also vice chairman of the task force weighing the new guidelines. “We don’t think that’s likely to happen, based on our assessment.”
The psychiatric association, based in Arlington, Va., is scheduled in May 2013 to publish its fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, the definitive resource used by doctors to diagnose, study and treat illnesses. The autism change, first proposed in February 2010, would be included in that edition, if it is approved.
Autism now includes a range of complex disorders characterized by social impairment, communication difficulties, and restricted, repetitive patterns of behavior, according to the National Institutes of Health in Bethesda, Md. About 6 children in 1,000 will have autism, the NIH said.
The field trials involved about 600 people with several closely related conditions, Regier said in a telephone interview. He declined to give precise results from the tests because the findings haven’t been presented in public or published in a medical journal.
The latest research counters a study reported at a medical meeting in Iceland that found the proposal may exclude many patients. Investigators from the Yale School of Medicine in New Haven, Connecticut, analyzed data collected in the early 1990s, almost 20 years ago, from trials conducted when the last diagnostic manual was released.
Using information from several hundred high-functioning people with autism spectrum disorders, they found that about half would no longer meet the criteria under the new definition being considered, said James McPartland, director of the Yale Developmental Disabilities Clinic in New Haven, Connecticut, and a researcher in the study.
“The implications of the study is that there is going to be a change in who receives a diagnosis,” McPartland said by telephone. “All this is very preliminary. This is a piece of information to be considered as the task force moves toward a finalization of the criteria.”
The new guidelines are designed make the diagnostic criteria clearer and more consistent for autism disorders. While there are several terms now that describe related conditions, including autism, Asperger syndrome and childhood disintegrative disorder, they have overlapping characteristics and it is often difficult for clinicians to tell them apart.
The new designation folds in six existing individual conditions and places them on a scale, called autism spectrum disorders. The description is more precise about what constitutes the symptoms, said Catherine Lord, director of the Institute for Brain Development at New York-Presbyterian Hospital in New York.
“The intention isn’t to exclude people who meet the criteria for any of the conditions,” said Lord, who is also on the task force considering the change, in a telephone interview. “It’s just to be sure we aren’t including everyone who has any kind of behavior problem.”
The old approach focused on meeting six broad behavioral criteria. The new proposal breaks the guideposts down into two distinct areas, communication and repetitive behavior.
Under communication, autistic people are those who will have trouble with relationships, nonverbal communication such as making eye contact or using gestures, and with social reciprocity, such as taking turns or holding a conversation. They must exhibit symptoms in each of these areas to be diagnosed under the new plan.
With behavior, patients may have to meet only two of the criteria among actions such as having limited interests, getting stuck on repetitive activities, having strong or muted responses to sensory stimulation like sound and taste, or developing rituals. The behaviors may have been in the past.
“The new criteria are somewhat stricter,” said Geraldine Dawson, chief science officer of Autism Speaks, an advocacy group based in New York. “There are a group of people who previously had Asperger Syndrome or high-functioning autism who are now no longer meeting the criteria.”
The issue isn’t semantic, Dawson said in a telephone interview. Patients need to be diagnosed to get access to treatment such a behavioral intervention, social skills training and support services, she said.
“From the scientific side, the changes make a lot of sense,” she said. “It’s a question of how this might impact services. We need to think through the implications for a well- reasoned change or the real people who are in the real world trying to obtain the services they need.”
The important next step, Dawson said, is to collect “very careful data on that and see what changes need to be implemented in how we qualify people for the services.”