For the one in every 100 or so children in this country with autism, a diagnosis is a critical link to treatment and services. It means that school districts will provide extra resources, and insurance carriers will pay for medical and psychiatric treatment.

The word itself has been in use for more than 100 years, but as the psychiatric community prepares to update the definition of “autism,” many parents have panicked, fearing that if the definition changes, their kids will lose the diagnosis and the services that go with it.

The latest evidence suggests that most families need not worry.

“I’m looking at all the kids I’ve tested and I just don’t see that [happening],” says Karen L. Schiltz, Ph.D., a psychologist in private practice in Calabasas since 1988 and author of Beyond the Label: A Guide to Unlocking a Child’s Educational Potential (Oxford University Press, 2011). “I actually felt really relieved when I saw the new definition come out.”

The definition in question is part of the upcoming fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Published by the American Psychiatric Association, it sets the standard for how health-care providers classify mental disorders. The book first listed autism as a unique diagnosis in 1980, but its definition hasn’t been revised since 1994. Meanwhile, the number of children diagnosed has skyrocketed, jumping 78 percent in the past decade.

No More Autism Sub-Categories

One reason the update is causing such a stir is that the proposed definition in DSM-5 collapses a whole range of autism spectrum sub-categories into one single diagnosis. This means that diagnoses like Autistic Disorder, Asperger’s syndrome and the umbrella term of “Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS)” would go away, leaving only autism spectrum disorder (ASD) as a clinical label. Many parents have expressed concerns that their child’s diagnosis will disappear along with the subcategories.

Going forward, “the job of a clinical psychologist is to answer a question of, ‘Is it ASD or not,’ rather than, ‘Is it Autistic Disorder or Asperger’s disorder or PDD-NOS,’” says Marisela Huerta, Ph.D., a psychologist at Weill Cornell Medical College in New York. But, she says, parents don’t need to worry. A recent study led by Huerta suggests that most kids with a current diagnosis on the spectrum would keep that diagnosis under the new guidelines.

There’s no harm in eliminating the sub-categories, Huerta says, because research over the last decade fails to identify differences in the clinical presentation (or the range of symptoms) associated with Autistic Disorder, Asperger’s disorder and PDD-NOS. “More importantly, we’ve learned that the different DSM-IV categorical diagnoses are not used in a consistent manner by clinicians,” she says. One recent study even showed that the clinic where a child was evaluated was a more important factor than the child’s actual symptoms in the specific autism diagnosis they received, with some clinics seeming to favor one sub-category over another.

Including New Symptoms

And while it offers only one diagnostic label, the proposed overhaul is actually more inclusive in some ways than the current definition. The new definition would:

• Include sensory interests and aversions among the symptoms used to define ASD – These symptoms – being especially picky about food or irritated by the texture of clothing, for instance – aren’t included in the current diagnosing criteria.

• No longer require that a child exhibit evidence of developmental delays before age 3 – Instead, the definition would require that a child show examples of unusual behavior “in early childhood,” making it easier for clinicians to diagnose children whose delays weren’t noted early on.

• Account for the fact that social impairments may change over time – ASD may look different at age 3 than, say, at age 10 or 30.

The new definition is also more specific and makes it easier to tell the difference between autism and other disorders. Speech delays, which occur in kids with autism but also in those with a range of other problems, have been removed from the criteria. Meanwhile symptoms that are unique to autism – including repetitive movements like arm-flapping, rigid adherence to routines or rituals, and unusually intense or odd interests – must now be present for a diagnosis.

“A large body of research over the last decade has demonstrated that nearly all children with some form of autism demonstrate these types of behaviors at some point in their lives,” says Huerta. “The presence of these behaviors, alongside a pattern of social and communication difficulties, is unique to autism spectrum disorders.”

Huerta’s study, the largest to compare existing diagnostic criteria with the proposed changes, included data on 4,453 children with an autism spectrum diagnosis. She and colleagues reviewed detailed parent reports on the children, and applied the newly proposed criteria. It turned out that 91 percent of the children would be diagnosed with ASD under the new guidelines based on parent reports alone, and Huerta believes that clinician input would clinch a diagnosis for many of the remaining 9 percent. Her study appeared in a recent issue of the American Journal of Psychiatry.

Schiltz, who specializes in neuropsychological assessment, believes the new criteria could even eliminate roadblocks to diagnosing some kids – especially those whose delays were “camouflaged” during the early years. “A kid who played in the sandbox for hours and hours in early childhood seems normal,” she offers as an example, noting that if parents don’t notice that something isn’t right by the time their child is 3, it can be tough for them to get help.

The common question from parents has been, “Why wasn’t this diagnosed earlier?” Schiltz says.

Advice for Parents

The specific autism guidelines in DSM-5 are still under review, and won’t become official until 2013. But Schiltz says the new criteria and definition are only the beginning. You still need a thorough evaluation of the child in order to make a correct diagnosis.

“It takes years and years of experience to understand the complexity of autism,” she says. “When we assess children, it’s a process.”

She advises parents who suspect their child might have a problem to take good notes. “I encourage parents to write things down when you see something that’s not quite right,” she says. Take that list to your pediatrician, ask for a referral to a psychologist, and get another opinion if you feel you weren’t heard. Once you have your referral, Schiltz says, a quality evaluation will:

• look at all possible causes for the behaviors your child is displaying;

• look at your child in all of her different environments (i.e. at home, at school, with caregivers and peers);

• provide an accurate roadmap of all of your child’s strengths and weaknesses; and

• include input from parents, teachers and other caregivers.

The proposed new guidelines, Schiltz says, won’t alter the process a good psychologist goes through in making a diagnosis. But because the criteria are more specific, in some ways the process will be easier. “The way we evaluate will not change,” she says. “[But under the new guidelines] we have more items to look at, and less to argue.”