Is there more autism? Or just a new definition?

2003-04-08
by Lindsey Tanner
The Associated Press
 

CHICAGO -- Mention autism to parents, doctors and scientists these days, and among an earful of different theories will emerge a common nod of agreement: The perplexing condition is not nearly as rare as once was thought.

As recently as a decade ago it was estimated that only about 4 per 10,000 children were affected. Research now suggests the rate may be at least 10 times higher.

The numbers have fueled debates over whether there's been a true surge of cases and whether environment or genetics could be the cause. Some parents and research advocates blame vaccines despite recent evidence to the contrary.

But many mainstream scientists point to two much less worrisome explanations: The definition for autism has changed and schools now offer more educational services to autistic children.

In 1991, the U.S. Department of Education made autism a new, separate category for special education services offered at public schools. Those services tend to be broader and more intensive than for other disorders, including mental retardation. There's evidence that the 1991 change prompted what some call ``diagnostic substitution,'' said Dr. Fred Volkmar, a Yale University autism researcher.

``Autism is kind of a fashionable diagnosis,'' Volkmar said. ``Everybody's interested in getting better services.''

Statistics seem to back up the theory. Department of Education figures show that the number of children getting services for mental retardation fell from 553,262 in 1991-92 to 532,362 in 1992-93. During those same years the number of children getting services for autism swelled from 5,415 to 15,580.

The change in school services and the definition, along with research showing that early intervention could help, raised awareness of the condition.

Autism used to be thought of as ``the kid who sits in a corner watching the record player go around and around. Everybody said that's what autistic is and anything else is not,'' said Chicago pediatrician Dr. Joel Schwab.

Schwab said that like many doctors, he may have inadvertently diagnosed autistic youngsters a decade ago as being mentally retarded, or with nondescript behavior problems.

Now, autism is increasingly recognized as ``being more than just the classic picture,'' said Schwab.

Molecular biologist Andy Shih, director of research and programs for the National Alliance for Autism Research, says that whether or not there's been a surge in cases, ``what is clear is that autism is a serious public health issue.

``With potentially 1 million Americans afflicted with this disorder,'' Shih said, ``it is no longer something that is rare or seldom seen.''

The impact has reached far outside the medical realm.

Many schools are struggling to provide enough services to affected children, funding for research into causes has grown, and lawsuits blaming vaccines are proliferating.

``There's just so many kids who have been affected, it's hard to find somebody who doesn't know somebody who has a kid with autism,'' said Liz Birt of Wilmette, Ill., whose 9-year-old son, Matthew, is autistic.

Within seven blocks of their suburban Chicago home, five other children also are afflicted. ``It's just rampant,'' Birt said.

Autism even ended up in a debate over a last-minute provision attached to Homeland Security legislation enacted last fall. The provision, aimed at protecting drug makers from lawsuits over vaccine-related injuries, prompted vocal protests in Washington in January by parents who think childhood vaccines cause autism.

Much has been learned about autism in the past half century. The once prevailing ``refrigerator mother'' theory suggesting cold, aloof mothers caused autism was long ago thrown out as scientific advances favored a biological cause.

But many key questions remain. Researchers don't know if a single gene or many are involved, or possibly different ones in different cases.

Some think environmental factors might trigger the disease in genetically susceptible people. Potentially plausible but unproven triggers range from illness during pregnancy to soil toxins, electromagnetic waves and even vaccines, though strong evidence so far suggests the shots are safe.

``There's so many things that it could be,'' said Dr. Robert Byrd of the University of California, Davis. A recent study suggested autism cases in California surged nearly 300 percent over 10 years, and Davis researchers are trying to pinpoint why.

The clamor over causes and numbers has prompted a call for the American Medical Association to investigate.

Autism has raised deep questions ever since psychiatrist Leo Kanner first described it as a distinct developmental disorder in the early 1940s, after observing several curiously afflicted children in Baltimore.

It remains ``a particularly challenging mystery,'' said Steve Foote, director of neuroscience and basic behavioral science at the National Institute of Mental Health.

Kanner described what is now known as classic autism -- children with severe impairments in language and communication, who may appear deaf, sometimes don't speak, show little eye contact and appear more interested in interacting with objects than with humans. Repetitive behaviors such as rhythmic finger tapping or ball-rolling are common.

Sometimes symptoms show up in children who previously appeared to be developing normally; some call this regressive autism.

It was initially linked to schizophrenia until 1980 when it first appeared as a separate disorder called ``infantile autism'' in the American Psychiatric Association's manual defining mental disorders. It has been redefined twice in updates of the manual.

Autism is not curable but can be helped with behavioral treatment and sometimes medication.

``People have a much better idea about the diversity of autism. There's such a range of both severity ... language handicap and mental retardation,'' said prominent autism researcher Catherine Lord.

``That has changed perspective on autism both in terms of figuring out who needs services and also the prognosis for people in the mild range,'' said Lord, director of the University of Michigan's Autism and Communications Disorders Center.

Not all children with autism are mentally retarded but most need special services.

Kathy Gould, project director for an Illinois program that trains teachers and parents how to work with autistic children, said demand has increased significantly in the past five years.

``Every day, more and more people in more and more district schools are saying these kids are coming in and we don't know what to do with them,'' Gould said.

``Parent workshops have gone from three a year to 15 a year. Parents are crying out for additional help,'' she said.

Liz Birt is among them.

Her son, Matthew, developed normally until he was 15 months old, when he could count to 10 and say about 30 words. He developed autism symptoms gradually after receiving two childhood vaccinations on the same day, Birt said. He stopped talking, acted as if he was deaf, spun in circles, stared at lights and shunned his family.

At 9, Matthew Birt is still profoundly affected and his mother worries that as he grows into adulthood, no services will be available.

``Somebody's got to pay attention to this,'' Birt said. ``We're talking about hundreds of thousands of children who are going to be a big drain on the economy.''

An attorney, she says she'd like to sue vaccine makers but can't because of legal restrictions against suits filed more than three years after a child's first symptoms.

Vaccine foes like Birt point to a 1998 British study linking autism with the measles-mumps-rubella vaccine. There's been a subsequent backlash against vaccines in England -- and recent measles outbreaks.

The Institute of Medicine reviewed the issue and in 2001 said there was no proof that autism is caused by the MMR vaccine or by the mercury-containing preservative thimerosal that was present in some vaccines.

Vaccine foes note the IOM report said a link between thimerosal and an increased risk of neurodevelopmental disorders is ``medically plausible.''

Dr. Neal Halsey, an influential vaccine proponent from Johns Hopkins University, agrees that thimerosal could theoretically be linked with subtle developmental problems including delayed speech, ``but the available data show no evidence of an association with autism.''

``Ongoing studies should answer the question about other neurodevelopmental problems in about one year,'' Halsey said.

After evidence in 1999 suggested that the combined amount of thimerosal in vaccines could expose children to mercury exceeding recommended maximum levels, Halsey worked with the American Academy of Pediatrics and the U.S. Public Health Service in urging vaccine makers to discontinue thimerosal use. Now, no vaccines given to children under 6 months of age contain thimerosal, he said.

``I do not, and never did, believe that any vaccine causes autism,'' Halsey said.

Ironically, the opposite may be true, he said, since women who develop German measles (rubella) early in pregnancy face an increased risk of having an autistic child.

Not all researchers are convinced that there is no autism link, and the National Institutes of Health is funding studies to investigate. NIH funding for autism research has grown along with the number of cases, from $22 million in fiscal year 1997 to $73.85 million last year, Foote said.

Recent research has led to important discoveries, including evidence that intensive behavioral training starting as early as infancy can substantially improve symptoms in some autistic children.

Volkmar, at Yale, and colleagues have found that while healthy babies learn social interaction by focusing their gaze on people's eyes, autistic children focus more on mouths.

This could help parents and doctors identify affected children earlier and get them early intervention, Volkmar said.

Other scientists are searching for genes and other ``biomarkers'' that might make autism as easy to diagnose as a simple blood test. For now, doctors still rely on behavior to diagnose autism.

Studies of identical twins, whose genetic makeup is nearly identical, have shown that if one has autism, the other faces at least a 90 percent chance of having severe social impairment, said Dr. Edwin Cook of the University of Chicago.

But pinpointing which combination of genes are involved could take years, he said.

``There's just too much we don't know,'' Cook said.

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On the Net:

NIH: http://www.ninds.nih.gov/health--and--medical/pubs/autism.htm

NIH research: http://www.nichd.nih.gov/publications/pubs/autism/mmr/sub4.htm

National Alliance for Autism Research: http://www.naar.org

Autism today encompasses far more symptoms than 20 years ago

CHICAGO -- Here is how the definition of autism has changed:

--The third edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, published in 1980, for the first time classified a distinct disorder called ``infantile autism.''

--A 1987 update of the DSM manual introduced the term ``autistic disorder'' and grouped infantile autism in this category along with childhood-onset pervasive developmental disorder, which described symptoms similar to those of autism but less severe in some cases, not all beginning in infancy.

--In 1991, the U.S. Department of Education made autism a separate category for special education services offered at public schools. Previously it had been lumped in the category ``other health impairments.''

--A 1994 update of the DSM manual lumps autism under a broad category called ``Pervasive Developmental Disorders,'' which some refer to as ``autism spectrum disorders.'' These include ailments such as Asperger's Disorder, sometimes called high-functioning autism; Rett's Disorder, a more severe form affecting only girls; and Childhood Disintegrative Disorder, a loss of previously learned abilities such as language and motor skills by age 10.

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