Anchorage Daily News

With the number of diagnosed cases sharply on the rise, is there an autism epidemic in America? If so, what's causing it?

Clinical psychologist Susan Hepburn -- an authority on autism who is traveling across Alaska this week addressing rooms packed with parents and teachers -- expects to hear those questions a lot.

For good reason.

While the incidence of autism cases among U.S. children in the early 1990s was about one in 2,500, today it's about one in 150 to 250 (depending on the study), Hepburn said by telephone before addressing a group in Juneau on Thursday.

That's partly because the old definition of autism -- a brain disorder in children that impairs social interactions and communication and causes repetitive behaviors -- has evolved in recent years.

Now the medical community recognizes a "spectrum" of autism disorders, including "passive," "partial" or "mild" autism.

"It isn't a black-and-white (diagnosis) where you fall into a disorder or you don't," Hepburn said. "It's more like a gradient or a continuum."

About a third of the 550,000 U.S. children and young adults under 21 now diagnosed with an autism spectrum disorder display symptoms of "classic autism," Hepburn said.

So broadening the definition to include the others types may have led to a three-fold increase. But that wouldn't explain the overall 10-fold increase in autism spectrum cases since the early 1990s.

Then what does?

"That's like the million-dollar question," Hepburn said.

An award-winning teacher of child psychiatry at the University of Colorado and sought-after lecturer on autism, Hepburn was invited north by the Alaska Autism Resource Center, which partly sponsored her trip.

She's due to speak in free public forums in Fairbanks on Monday and Anchorage on Tuesday. Those who wish to attend should contact the center at 334-1300. Information is also available at alaskaarc.org.

An abridged version of Hepburn's interview with the Daily News follows.

Q. What's causing the autism caseload to rise?

A. There are several researchers who are looking at that right now. In fact the Centers for Disease Control (and Prevention) has funded a study (with 5,000 families over 10 years) that's looking at a whole host of environmental variables, biological variables and trying to come up with some sense of what could be causing autism.

We'll probably find out that what we're currently calling autism is actually several different conditions with different causal pathways. So scientists are also working at defining sub-types better. The second thing we know is that it's highly genetic. It's in fact thought to be one of the most heritable conditions of childhood.

When you look back on family histories, you see (a higher incidence of) depression and anxiety, which tells us something about the parts of the brain that might be involved. And also things like intellectual giftedness, or a desire to specialize. So it seems as though autism might be about not seeing the big picture very well, and not being a good generalist, but people who have a style that prefers to go deeply into one thing. That sort of runs in the family.

Q. What about possible environmental causes?

A. That's absolutely an area of inquiry. Nobody has come up with anything that holds across studies so far. ... (But) there are certain (geographical) pockets where autism seems to be more common. There is a place in New Jersey, for example, and another industrial area in Massachusetts. And so people are trying to understand: Could it be something in the environment that has made that happen? Or could it be that those industrial areas bring people in who have high-tech skills who are sort of genetically at risk?

Q. What's the verdict on whether certain vaccines cause autism?

A. That's one of the questions that motivated the CDC study. ... In trying to read though that research, a couple of things come to mind. One is: I don't think vaccines cause it for the majority of children. But I don't discount the idea that there could be a small percentage of kids -- maybe a sub-type -- who have an immune system difficulty. And I actually think the immune system is probably involved in autism. And so for that small percentage -- 3 to 5 percent who could be vulnerable when those vaccines are given several at a time -- it could be difficult for the brain to metabolize (the vaccines).

What gets tricky, though, when you look at studies like in Denmark -- where they're able to (track) the entire population of the country and did the vaccines and looked at what the rates of autism are, and then took the vaccines out and looked at the rates of autism -- and basically the rates of autism continued to increase. Suggesting that on a group level, vaccines are not the cause.

Q. Does autism evolve over time? Do children "out-grow" certain symptoms?

A. Absolutely -- yes. So while we know we're not curing it, because it really is the biological makeup of the brain that is different from birth in autism, we can definitely see some huge gains in social (interactions), communication, play ... Some doctors have started to use the term "residual autism," which basically means -- to somebody who doesn't know autism well -- this kid could look just like any other kid.

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