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Published: Oct. 16, 2006 at 5:13 PM
By DAN OLMSTED
UPI Senior Editor
WASHINGTON, Oct. 16 (UPI) -- The debate over the cause or causes of autism has
been hung up for years on a point that should have been settled by now: whether
the rate is in fact increasing.
This column long ago concluded that, yes, the autism rate has risen dramatically
over the past couple of decades. What's more, the disorder seemed to arise out
of nowhere starting about 1930.
Both those points are controversial, to say the least. If in fact autism went
from essentially zero in 1930 to 1-in-every-166 kids today, the prime suspect
would be some new harmful exposure, not merely better recognition of a genetic,
highly heritable disorder.
The issue can quickly get complicated: How do you define autism? How have the
diagnostic boundaries changed? Is an autism diagnosis being substituted for
mental retardation because it sounds less devastating or more, well,
fashionable?
But all this is not as hard to untangle as some parties would have you believe.
In 1943 a Johns Hopkins child psychiatrist named Leo Kanner identified the
syndrome in a landmark paper, "Autistic Disturbances of Affective Contact." The
11 case histories he described among children born starting in 1931 were
remarkably similar -- and "markedly and uniquely" different from anything
previously reported, Kanner said.
Ultimately, a broader spectrum of pervasive developmental disorders was included
-- from the milder Asperger's to Rett's Syndrome, which affects girls, to
Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS).
The severe form first described by Kanner came to be known as "full-syndrome,"
"classic" or simply "Kanner autism."
That easily identifiable disorder is what we want to compare. I've suggested the
current incidence of Kanner autism is somewhere between 40 to 60 children per
10,000; when you add in the other disorders on the spectrum, it rises to 60 to
80 per 10,000.
Of course, there is debate and uncertainty -- but within fairly tight
parameters. Dr. Deborah Hirtz of the National Institute of Neurological
Disorders and Stroke -- part of the
National Institutes of Health
-- estimates that about 10 to 30 children per 10,000 have classic autism today,
and a combined total of 30 to 60 have one of the pervasive developmental
disorders.
That's slightly lower than my numbers, but on the same order of magnitude.
Too bad, some say, we can't match those up with reliable figures from before
1980; then we would know if we're facing a real increase. The most frequent
objection is the lack of a large, pre-1980 "prospective" study -- one that
followed thousands of kids and recorded which ones developed the classic signs
of autism. That would be a fair basis for comparison.
I've recently come across a 1975 study that does exactly that, although it was
not the purpose of the research. The study was designed to look at bleeding
during pregnancy as a risk factor for autism and childhood psychosis -- and did
find a correlation. To do so, it examined the computerized records of 30,000
kids -- a huge sample -- born between 1959 and 1965 at 14 university-affiliated
medical centers. All the children got several neurological, psychological and
speech and hearing exams by age 8.
Here's the key statement: "From this group 14 were selected as conforming to the
syndrome of infantile autism."
That translates to 4.7 kids per 10,000, way lower than any measure of today's
rate. The researchers wrote that although they "make no claim to having
identified every autistic child among the 30,000 children, the rate of 4.7 per
10,000" exactly matched another well-regarded study, "leading us to believe that
most such children were included."
But what about kids who back then were mistakenly labeled schizophrenic or had
other "pervasive" disorders that now would land them on the autism spectrum?
Well, the researchers studied the records again and, this time, identified
"additional children who, although not having the classical syndrome of
infantile autism, were apparently psychotic. Six such children were found, all
labeled by at least one observer as severely disturbed, psychotic-like,
autistic, or childhood schizophrenic."
So let's include them in our "autism spectrum." That gives us 14 classically
autistic kids, plus six more with some sort of severe developmental disorder,
for a total of 20 kids out of 30,000.
Again, the math is simple -- that's just 6.7 kids per 10,000, far below even the
low-end estimate of 30 per 10,000 for all the spectrum disorders today cited by
the NIH's Hirtz.
The study was published in the highly credible "Journal of Autism and Childhood
Schizophrenia" in 1975. And get this: "Children with infantile autism and
childhood psychosis were identified by the National Institute of Neurological
Disease and Stroke Collaborative Pre-Natal Study." That's Hirtz's institute.
We're talking apples and apples, and a lot more of them today than 35 or 40
years ago. The implications are as disturbing as they are (or should be)
obvious.
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