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INTERVIEW: Walter Zahorodny, PhD on the unrecognized autism epidemic

Updated: Feb 21

Walter Zahorodny, PhD from Rutgers University in New Jersey was interviewed by Jill Escher recently.
Autism's Rising Rates: A Deep Dive into Autism's Increasing Prevalence and 50 Years of Data

Jill Escher is the president of the National Council on Severe Autism, and a board member of Autism Society San Francisco Bay Area.

Dr. Zahorodny's interview starts at 54:45

New Jersey numbers are the best in the United States.

Dr. Zahorodny said he was providing twenty years of information in approximately ten slides which are organized according to what I consider to be the main findings or the main themes of our findings.

Autism is a highly prevalent disorder. Within a generation, we’ve seen autism, which used to be considered by everyone quite correctly as a rare disorder, as affecting at least three percent of eight year old children.

In some selected counties and regions of New Jersey, as many as five to seven percent of the pediatric population.

There’s no doubt that autism is much more prevalent than many other childhood disorders and many more, much more common than many frequently encountered childhood diseases.

There’s no doubt as well that while New Jersey’s rate is quite high, we’re not the only region with high rates, but that these high rates are now reflected from data in California. 

My second and third premises or statements of what’s essential reflect the fact that autism has increased very dramatically in the sixteen year period from 2000 to 2016.

It’s increased across all subgroups, all forms of autism, across all demographic groups.

It’s increased in New Jersey from approximately one percent, 9.9 per thousands to now 31.4 per thousand, or three percent.

The trend identified in New Jersey is clearly mirrored or reflected by the trend the overall ADDM Network. . . .

Before the 1990s, autism prevalence was correctly identified to affect approximately 1/10th to 2/10th of a percent.

When a high identification of autism in Brick Township in 2001 called attention to this fact, another couple of years of work had to elapse before the ADDM Network identified overall prevalence to be .6 per thousand, while in New Jersey, it was .9.

As you see, the rates went up without cessation and without plateauing continuously.

The fourth object of my attention is that autism, in spite of better awareness, better recognition, is still widely UNDER DIAGNOSED.

We find that overall, in the period from 2000 to 2016, there was improvement in the rate of autism diagnosis. This was a significant improvement.

Nonetheless, even as late as 2016, twenty-two percent or one in five eight year olds who satisfied the case definition, who met the criteria for autism by our independent surveillance, did not have an autism diagnosis. . . .

So autism is prevalent. It increased. New Jersey was a leading indicator.

And now we also understand that even in spite of better awareness, the true prevalence of autism is not merely the diagnosed cases. We still lag in our identification of autism prevalence. . . .

Poor and minority children with autism are diagnosed later.

From 2000 to 2010, across many studies, not only by the ADDM Network, but by New Jersey investigators, we found a very strong positive association between socioeconomic status and autism prevalence. . . .

Twice as many children with autism would be identified in high in high income compared to low income communities. We thought at some point this would begin to decline, but it stayed consistent for a ten year period.

Since 2010, we’ve been finding and confirming in New Jersey, as well as in the ADDM Network, that now this wealth gradient . . . is now reversed.

Now we’re identifying greatest rates of autism prevalence in low and middle income communities.

Equally interesting is the fact that since 2010,2012, Hispanic children with autism are showing the strongest acceleration in autism prevalence estimates.

This is very puzzling and underappreciated, this shift in the autism gradient because we would understand why over time children from underserved communities would equalize in their estimate. . . .

It’s not at all clear why their estimates should grow higher, beyond the rate found in high income communities. 

Zahorodny explained his research on adolescents with autism.

Three out of five, or 59 percent had other co-occuring neuro psychiatric problems or disorders like mood disorder, anxiety, ADHD and the like.

More than one in three or 35 percent had co-occuring intellectual disability. Difficulty learning and using information efficiently is an important addition to the main presentation of autism and makes the care and intervention needs all the greater for a significant group of individuals. 

Adolescents, like younger children, were found to be underdiagnosed.

Even at age sixteen, one in four adolescents with autism were undiagnosed. They were diagnosed with other conditions or other concerns, but not with autism.

They also found that autism was twice as common in high income communities as in poor communities.

Predictions/projections for the near future:

Autism prevalence for 2022—that is for the next surveillance cycle—will be higher than found previously. This is inevitable because autism prevalence has not peaked. Even in the most recent surveillance and still higher estimates are likely as we acquire better ability to identify minority and low SES individuals. . . .

Finally I would predict that the next report from the ADDM Network will not reflect significant public health concern or propose understanding autism risk factors or promotion of early detection.

Most likely the next report will mention better awareness and recognition as possible factors bearing on higher estimates.

This is a standard, almost magical Cohen that comes up every time the prevalence estimates are provided.

We really don’t understand what’s driving autism prevalence.  We don’t know the risk factors, so the best one can say apparently is that the increase might be due to better awareness or recognition.

Nonetheless, we should be thinking of what to do better and what to do for the future.

Without a doubt, the most important factors or improvements that we could recommend involve enhancing and promoting studies which attempt to identify autism risk factors and triggers.

These are not genetic factors. These are environmental factors and it’s necessary to understand which ones are driving and have driven autism prevalence twofold and threefold over the last fifteen years.

Since we don’t yet understand, and I see no prospect for understanding the autism risk factors or triggers in the near future, I think it’s very important that we try to promote universal autism screening of toddlers and preschool aged children. . . .

Given the high an escalating rate of autism in our population . . .it’s essential that from the policy perspective, we plan and provide resources for care, services and interventions to individuals with autism, that we understand that autism is a lifelong condition. . . .

He went on to say we know nothing about adults with autism .

He referred to autism as a “public health phenomenon and crisis which calls for a lot of attention and a lot of action."


Zahorodny was asked why there are such strong denials of a real increase in autism.

Unfortunately, no agency or program in the United States has the resources as the CDC to identify the potential risk factors for autism, and they’ve committed the most resources to identifying and to understanding this phenomenon, and yet we’ve gotten nowhere.

I’ve been part of the ADDM Network since 2000, and so I was there at the initiation and across the development and enhancement of the network. I think when we started there was true interest and excitement and surprise regarding the first of all high rates and the escalation of rates, but somewhere after third or fourth cycle, it become clear that there were no plausible ideas or hypothesis that the CDC felt compelled to investigate.  It would be therefore less complicated and less dangerous to prevail with a search for risk factors.

It would be much less controversial to acknowledge what is possibly responsible for a small increase in case determination, that is better awareness.

It’s uncomfortable to identify a phenomenon and not to be able to explain it. 

If I were to say, if I were to conjecture what a motive could be by some organization such as the CDC, I would be implying something in that direction.

In addition, in the ivory tower, for every creative, open individual, there are five to ten who are likely to repeat what is considered to be the standard wisdom about a phenomenon. The explanation of escalating autism based on better awareness is hard to puncture once it’s established because people resort to it automatically.

Without there being a well identified set of hypothetical risk factors, it’s just easier to retreat behind the concept of better awareness.

He went on to say that he’s never met anyone dealing with these children in the medical or educational system who doubts this is a true increase.


The first wave of speculation in this field was concerning vaccination and the vaccination hypothesis, though wrong, was very compelling on a number of grounds, and it was very distressing to the Centers for Disease Control to have that hypothesis out there.

Once the hypothesis was debunked or failed to gather evidence, supportive evidence, and no other hypothesis that was compelling enough come into the field, and so we’re kind of stuck repeating the same pseudo explanations. 

Zahorodny said other research looking at perinatal factors like low birth rate can’t explain the autism increases.

Escher added that the claim of a link between vaccines and autism fueled the drive to deny any increase in autism.

Zahorodny was adamant that autism has dramatically increased in real numbers, dismissing the claim of greater awareness.

Better awareness would imply also a dramatic shifting in human consciousness or awareness of something or a dramatic escalation in our ability to classify.

It cannot expand indefinitely.

If some new phenomenon appears in our consciousness, we start understanding it and labeling it, and we get better at it.  But it doesn’t go on indefinitely over a decade or generation. 

Zahorodny was asked about the changes regarding autism in the DSM IV and the DSM 5.

We tracked DSM IV and DSM 5. We did it simultaneously in the years before and after the shift.

The shift occurred in 2013. That’s when the DSM5 came out. 

When we tracked according to both systems, the DSM5 estimate was slightly lower than the DSMIV estimate. The DSM5 criteria in my opinion are narrower and slightly more specific and more difficult to satisfy, especially more difficult to satisfy in a young child.

I prefer the wider net provided by DSM IV. . . . 

Escher went on to cite the influence of the neurodiversity movement in denying a real increase in autism because of their premise “that autism is natural, and autism’s always been here. It’s an important part of human diversity.”

Escher pointed out a comment submitted by a listener who said her service coordinator has a case load that’s 78 percent autism.

Escher: I don’t doubt that at all. Pretty soon our DDS system is going to be autism and some other stuff.

Zahorodny: I would imagine if somebody researched the constituency of the early intervention programs, they would also find a high proportion of them have autism. 

Escher went on to talk about autism research.

I would say the major funders have stopped funding meaningful biological research into autism, have given up on looking for causes of autism.

The major funders are the NIH, and the major private funder is the Simons Foundation.

As I said before, the Simons Foundation is exclusively devoted to genetics and really doesn’t care about any possible environmental factor, even the gene, environmental work that I do.

Autism Speaks, which used to be very devoted to finding exogenous causes of autism risk, has given up on it completely, and all of their research money goes into genetics. They don’t do any environmental work anymore.. . .

I would do anything to prevent autism in any child. I want to make that clear, and it’s amazing how we’ve all rolled over and we seem to just sort of accept that more and more and more kids are going to be permanently mentally disabled with a serious disorder.  We kind of color it as something that’s diversity and something to be celebrated.

It boggles my mind. My brain cannot comprehend this. 

Zahorodny was asked about the 160,000 children in the U.K. waiting for an ASD assessment.

Zahorodny:  In the ideal world in the short term, look beyond the medical subspecialist.  At this moment, the vast majority of individuals are diagnosed by developmental pediatricians or pediatric neurologists.

There are well-trained clinical psychologists who would be able to diagnose efficiently and correctly. . . . The future probably rests with nurse practitioners, advance practice nurses who are well trained in their educational background.  . . .

 Escher: I’ve been seeing some of these articles about the waitlist for diagnosis in the U.K. You saw what the prevalence numbers already are. They’re already three percent in the U.K., so it makes me wonder, what is going on there?

How higher can it go?

Here in the U.S., we also see waitlists, but the U.K. has more centralized data which makes it  a little more compelling.


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