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DBL%20Hendrix%20small.png College chemistry, 1983

Derek Lowe The 2002 Model

Dbl%20new%20portrait%20B%26W.png After 10 years of blogging. . .

Derek Lowe, an Arkansan by birth, got his BA from Hendrix College and his PhD in organic chemistry from Duke before spending time in Germany on a Humboldt Fellowship on his post-doc. He's worked for several major pharmaceutical companies since 1989 on drug discovery projects against schizophrenia, Alzheimer's, diabetes, osteoporosis and other diseases. To contact Derek email him directly: derekb.lowe@gmail.com Twitter: Dereklowe

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May 4, 2011

What Autism Epidemic?

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Posted by Derek

There's a new study out looking at the prevalence of autism across different age groups across the United Kingdom. Since autism shows up in childhood, if the rate of its occurrence had changed over the years, that would be expected to be preserved in the population as you move up in years. But it doesn't.

It absolutely doesn't. Despite report after report of an "autism epidemic", what this study supports is the idea of an increase in diagnosis, not in the underlying condition. None of the adults surveyed who fit the autism criteria had any idea that they did so: they never knew that they were autistic, and had never been diagnosed. (I've no doubt, though, that they or their neighbors were aware of their seemingly eccentric personalities). These people also turned out to be generally socially and economically disadvantaged, which given what they've had to work through, I can well believe.

But there was no change related to age group. The demographics were what you find in current children: about 1% of the total population, males much more common than females. No change. No sign of an epidemic. But it won't change a thing for those people who are convinced that one exists; they'll already be out there today telling everyone about the flaws in this study, its biased nature, its gaps and omissions. Dark forces will be alluded to, huge conspiracies - and if you doubt that, just watch the comments to this post, because I'll probably attract some of these people, too.

Comments (47) + TrackBacks (0) | Category: Autism


COMMENTS

1. Rick on May 4, 2011 8:12 AM writes...

Sadly, the quality and conclusions of the studies are of limited importance in shaping public or private sector policy. What matters most is what the public can be convinced of and whether money can be made off of that belief. Polls suggest that people are very credulous with respect to an autism epidemic, as well as certain alleged causes and treatments. There's money to be made in that and consequently, shareholder return to be maximized. Policies will reflect that.

Permalink to Comment

2. anchor on May 4, 2011 8:30 AM writes...


Truth be told, autism is a real 'neurological" conditions. It is out-drowned by the fraudulent paper that was published in Lancet (later to be retracted). This present finding from UK does not add anything valuable. There was also a recent paper that a gene for the autism was identified.. Suffice it say that autism has been attracting lot of funding with very little show at the end of the day.

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3. You're Pfizered on May 4, 2011 8:31 AM writes...

As the father of an autistic child, I've been following the 'debate' over the last few years. I'm not sure if Rick's comments are meant to chastise the unscrupulous folks who prey on desperate parents, but they come across as somewhat cold and certainly bear no true understanding to what it's like to be the parent of a child who is struggling. Unless you've been there, you have no idea how hard it truly is. I can see how folks who have kids with severe autism could be swayed by ill-meaning people offering hope. My child is on the mild to moderate end and there are still days when I sit down and struggle with it all. I wouldn't wish this on anyone.

That said, there are therapy options that are quite good, and have had some success. By therapy I mean behavioral, speech, language, and occupational therapy approaches, not medications.

I do agree that the main thing that has changed over the last few yeas is increased awareness and the earlier diagnosis of children on the spectrum, which leads to earlier intervention, and, hopefully, a better outcome. The earlier you get started on therapy, the better chances you have that you child will be able to mainstream. It's still a long, long road.

A cure would be nice, but I know better than to ever expect that. Determining the root causes and/or genetic markers would be a start in perhaps even earlier intervention

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4. lt on May 4, 2011 9:07 AM writes...

How can there not be an autism epidemic when there are all those chemicals in our food?!? ;)

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5. Rick on May 4, 2011 9:37 AM writes...

You're Prizered (#3),
I most definitely meant to chastise the unscrupulous, and unfortunately inevitable, people and behaviors to which you referred. I am deeply sorry for the insensitivity my comments conveyed; it was not intentional. I know from personal experience how real and difficult the challenges of raising an autistic child can be. It makes me very angry to see predatory marketing and PR, often in the name of "education", take advantage of people's anxiety, be it over autism or any other medical condition, BUT if anger leads me to make comments that are insensitive to the people in need, it's wrong and it would be better if I kept my mouth shut. Please forgive me.

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6. Mike W on May 4, 2011 10:01 AM writes...

Yes, Derek, but have the authors of this study been on Oprah?

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7. You're Pfizered on May 4, 2011 10:09 AM writes...

No offense taken, Rick. I knew what you meant, unfortunately I've read many things from many folks who have no idea just how tough it is to be in the middle of it all. Desperate people can be easy prey for those with no scruples. Weeding through the legitimate options is hard enough, especially when it's your own child.

The peddlers of false hope, just to make a buck, those are the folks I have contempt for, and not for just people who go after those with autism. There are plenty of snake-oil peddlers out there for many disease states. Unfortunately, the pharma industry is often put into that same category by its critics...

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8. RD on May 4, 2011 10:32 AM writes...

I knew a family once that had not one but *three* autistic boys. To them, it was a bit of an epidemic but I prefer to think of it as an unfortunate cluster.

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9. PC on May 4, 2011 11:06 AM writes...

As I am also a father of an autistic child. I have to reinforce #3. The important thing is early diagnosis, but what many people with autistic children fear are budget cuts for intervention and treatment for children that are mild-to-moderately autistic.

I do believe that the "epidemic" is nothing more than better diagnosis and many autistic children of our generation and previous generations were just labeled as a problem child because their autism was only mild. Having said that, the extra press can only help local governments' causes to increase or even maintain current funding to the children that need it.

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10. Vader on May 4, 2011 11:12 AM writes...

I also knew a family with three autistic boys; I wonder if it was the same one? It's not common.

There were pretty clear indications that the autism in the family in question was heritable. Also present here and there in the extended family.

If it's genetic, there's probably no cure forthcoming. Doesn't mean there can't be helpful interventions, of course.

I worry the condition is being overdiagnosed, which is not good for those who are truly autistic. Whatever funding is available to help is going to be spread thinner.

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11. PC on May 4, 2011 11:33 AM writes...

Vader. that's one of the problems right now. There is no "truly autistic". there is severely autistic and then there are a myriad of autism-like disorders that all fit under the autism umbrella. For the children that are considered severely autistic, I doubt there will be a lack of funding to treat them. For the children with mild-to-moderate autism, they can lose the treatments they are receiving if funding is cut back.

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12. MTK on May 4, 2011 12:02 PM writes...

PC,

If what you believe, and what this and other studies seem to support, that rising autism prevalence is due to earlier and better diagnoses, and not a real epidemic then that's important for the general public to know.

a) We can stop all the anti-vaccine stuff
b) We can divert limited research dollars away from finding a cause in recent environmental changes and redirect them to other time-static factors or toward treatment.

Unfortunately, this issue has become so politicized and people have so much invested in their own personal beliefs that I doubt the science is going to have any impact on policy.

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13. Nick on May 4, 2011 12:07 PM writes...

I believe the autism epidemic is very similar to the attention deficit disorder epidemic (imagine 5 year old kids having trouble focusing on a warm spring day!).

The remedy for this plague is to jack up the little ones on a variety of pharmaceuticals. My guess is that their young bodies will be made forever dependent on ritalin or whatever.

They will thus require these drugs to feel 'normal' for the rest of their lives.

Great way for Pharma to expand its base of dedicated customers. Take a look at the list of drugs below for autism.

www.child-autism-parent-cafe.com/autism-medication.html

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14. PC on May 4, 2011 12:10 PM writes...

agreed MTK,
while I won't rule out an increase in autism due to environmental causes, I do believe that funneling money into autism vaccines or research programs to cure it are a complete waste of time.
Many people want to believe that we can cure anything if we throw money at it, just not very realistic.

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15. DrugA on May 4, 2011 12:20 PM writes...

This study confirms my instinctive bias, so I'm inclined to believe it. On the other hand, I spent some time a few years ago talking to a number of epidemiologists who work in this field. Several told that most, but perhaps not all, the apparent increase in prevalence could be explained by increased diagnosis. Are we at risk here of over-interpreting a single study. I haven't reviewed it, but it occurs to me that there could be methodological challenges in accurately calculating the prevalence of a condition across different age cohorts when diagnosis is based on clinical presentation, which surely changes as these kids age. I don't have a dog in this fight - I certainly don't believe it is vaccines or preservatives or a cover-up -- but any kind of observational study is limited. Might we be more accepting of the studies we like?

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16. MTK on May 4, 2011 12:39 PM writes...

DrugA,

This isn't the only study. There's been several studies which have reached similar conclusions and there was a book written in 2007 which stated the same thing.

I'm with PC on this one. I'm not ruling out that there could be an increase in prevalence or that environmental factors play a role, it's just that the orders of magnitude increase often cited seems dubious, particularly when one considers the changing definitions and increased awareness.

All of that doesn't change the situation for many, but it could, and should, change where we spend our research dollars.

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17. luysii on May 4, 2011 12:53 PM writes...

It's not clear if the article refers to 'pure' autism or autism spectrum disorder, a wastebasket diagnosis if there ever was one. A variety of genetic defects have been found associated with autism spectrum disorder, but most appear to be confined to a single family. For more details than you probably want on this, and for just how broad the diagnosis of autism spectrum disorder really is -- see http://luysii.wordpress.com/2010/07/29/tolstoy-rides-again-autism-spectrum-disorder/

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18. passionlessDrone on May 4, 2011 1:16 PM writes...

Hello friends -

The study in question is a total joke.

There were a total of 19 people that were given any kind of actual diagnosis. The male to female ratio was an astounding 9:1; compared to consistent 4:1 findings in studies involving tens of thousands of children.

The initial diagnostic tool in use, the ASQ, involved questions including the preference for fiction or non fiction as favorite things to read. Considering that ~30% of people with autism have IQ

Only people who were living at home were interviewed in this 'survey', so that means anyone with autism that was on the streets, in a mental institution, or in jail wasn't counted. The fact that this 'study' is hailed as evidence of anything tells us more about the deep seated need for a comforting story than anything.

The diagnostic issues are real, but are a type of sponge for any increase and are completely unfalsifiable; any amount of increase can be sucked up by the nebulous shifts in 'awareness'. There are at least half a dozen studies that consistently show that as parents age, their children have an increased risk of autism; and our parents have been aging. When faced with this fact, people will frequently say that "the rest" of the increase is driven by diagnostics; regardless of what that value might be.

Today a study was publised on children in Utah. 1 in 77 are on the spectrum.

http://www.ncbi.nlm.nih.gov/pubmed/21538173

Wake up people.

I must admit, I am more than a little bit shocked that so many readers of this board are OK with coming to conclusions on the scores of behaviorists considering just how much phsyiological information we have in this population. This is a question that will be answered eventually with bioinformatics; the psychologists will be left to rot.

- pD

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19. trrll on May 4, 2011 1:45 PM writes...

Most people with autism are receiving some kind of pharmacotherapy, but the medications used are mainly directed toward complicating symptoms that may interfere with education and behavioral treatment, rather than at the "core" symptoms, which so far have proved largely refractory to pharmacological approaches. So, for example, autistic children who are hyperactive may be treated with stimulants (although they don't seem to work as reliably as in uncomplicated ADHD) and autistic children with "obsessive" behaviors are treated with antidepressants, and so on. Much of this is more empirical than evidence-based. The boundaries between autism and other "autistic spectrum" disorders, such as Asperger syndrome, are fuzzy and the grouping is based upon behavioral commonalities rather than biological markers. It is becoming clear that there are some fairly large neurochemical differences in classic autism, but it is not known whether the same differences are present in others on the "spectrum."

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20. Anonymous on May 4, 2011 2:45 PM writes...

Only a bit off subject. When I was in school, there were one or two "hyperactive" kids. Now it seems ADHD is an "epidemic." Overdiagnosis here is pretty obvious, not exactly the same as "better diagnosis."

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21. Anonymous on May 4, 2011 5:37 PM writes...

@18: You have some good points. One point that you raise that I wonder about, however, is that the survey does not take into account people in jail, mental institutions, etc. I would think that those populations would lean more towards an older group, meaning that the younger population is actaully overrepresented in this study, reinforcing the conclusions drawn in the study.
I would be interested to know whether, despite the other flaws in the study, you think my point is valid.

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22. dave w on May 4, 2011 7:00 PM writes...

I'd agree with the comments on "changing definitions and increased awareness": it seems likely that many kids are now being diagnosed as specifically "autistic" who would historically been differently labeled: "learning disability", "atypical development", "behavior problem", "emotionally disturbed", etc....

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23. uep on May 4, 2011 8:27 PM writes...

Alternately, the lack of age-distributed rate increase may point to a cause that is not age-linked. Autism may not be caused at a defined moment in someone's life.

More cases may well be getting diagnosed, but more cases might also be getting caused or made worse, in older people, so as to be diagnosed.

Dietary factors contributing to auto-immune responses have been linked to many mental and neurological issues. Evidence is mounting for such links in conditions including epilepsy, MS, Alzheimer's, as well as the autistic spectrum.

Intestinal permeability (leaky gut) involves the same mechanisms (especially zonulin) as does the blood-brain barrier.

The findings of this paper may also be consistent with an increasing age-independent cause.

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24. MTK on May 4, 2011 10:11 PM writes...

@18,

You are wrong that 19 people were given any kind of diagnosis. The actual number is 7403. 7384 were determined not to have an ASD. That is a diagnosis, you know.

7403 is the number of respondents to the Phase I questionaire, the AQ-20. 5102 (AQ-20 >5) then were determined to eligible for progressed to Phase II. Of these 630 then were determined to be likely to have ASD based on validated probability scores determined by the questions answered on the AQ-20. 618 of these were then evaluated using ADOS-4 testing. They did diagnose 19 individuals with ASD. The numbers were then crunched with appropriate weightings based on general census numbers and the demographics of the 7401 respondents. The authors concluded that the incidence rate among adults in the UK is around 1%. You stated the seemingly shocking Utah number of 1 in 77. Sounds pretty close to 1% to me.

The important point here, which I don't think you are grasping, is not the actual prevalence rate, but rather that the prevalence rate was not age dependent in this study. The authors actually write that they hypothesized it would be and that they were surprised at the result. So they in fact went in looking for evidence of increased rate of ASD.

In other words, no one is saying that the autism rate is artificially high, rather that it was previously artificially low due to non-diagnosis. So if the oft-cited 1 in 10,000 rate of 40 years ago were true, these authors should have found way less than 19 cases.

This in no way diminishes the seriousness of ASD.

What it does do, if verified by further studies, is tell us what we can stop looking at from an environmental perspective. Much of the research conducted now looks at environmental factors which have changed over the last 30 years. This is based on assumption that the rise in autism cases over that time is real. If, however, ASD rates have actually not risen due to being artificially low then we need to look elsewhere.

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25. hayim on May 5, 2011 12:20 AM writes...

Re #17, and so somewhat off topic..

ASD may or may not turn out to be a 'wastebasket diagnosis', or even partly one, but whether it will or not may not have as much to do with genetics or biochemistry as you seem to be implying.

The brain's cognitive processes -- which surely must be considered the substrate upon which ASD conditions are expressed -- are not biochemical or genetic processes, but are built several layers above them. Many different biological changes may lead to the same changes in how our neurons fire and wire, and it is this level of activity that actually represents the machinations of the brain.

Furthermore, the existence of any single genetic or epigenetic trait implicated in one person's ASD may be completely benign in another's, depending additionally on hosts of other factors. How can you hope to assay for an entire history of developmental dynamics?

Sensible levels at which to group distinct phenomena are those at which they share commonality, causality or significance. For ASDs, the neural level generating the relevant cognitive characteristics probably satisfies all of these.

If ASDs dependent on gene X cannot be treated by the same methods as ASDs dependent on neo-natal environmental factor Y, then of course the grouping ASD ought to be subdivided to reflect this.

But it's still not clear that these ASD-X and ASD-Y would deserve promotion to their own categories, unless X/Y really were necessary and sufficient, and no treatments for any other ASDs helped the X/Y cases. But this may well indicate that the commonalities shared by other ASDs were misattributed to the X/Y cases in the first place.

Hmm. That became quite a ramble..

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26. luysii on May 5, 2011 7:51 AM writes...

#25 Here are the criteria for ASD of 7 years ago [ Cell vol. 119 p. 28 '04 ]

l. autism
2. Asperger’s syndrome
3. childhood disintegrative disorder (whatever that is)
4. Rett syndrome — this one has a known mutation causing it.
5. Pervasive developmental disorder not otherwise specified
Particularly note #5 — it lets in a lot of kids, and, as noted above, between 2- 3% of the population has an IQ 70 or below.

"Sensible levels at which to group distinct phenomena are those at which they share commonality, causality or significance. For ASDs, the neural level generating the relevant cognitive characteristics probably satisfies all of these."

I couldn't agree more. This is exactly how medicine has always progressed (grouping phenomena at levels at which they share commonality). Think back before Pasteur and substitute 'fevers' for ASD. Only after the zillion microbiological (and non microbiological) causes were studied and differentiated was progress made in diagnosis and treatment.


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27. Derek R on May 5, 2011 9:10 AM writes...

One problem with that study is it ignores the incidence of autism in the last 16 years.

A few recent studies have linked autism to the usage of antidepressants during pregnancy.

Try a google search for "Serotonin, pregnancy and increased autism prevalence: Is there a link?" and "Rats given antidepressants may help scientists understand, prevent autism".

(Figured links would be filtered, hence the google searches).

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28. MTK on May 5, 2011 10:12 AM writes...

@27:

The exclusion of people under the age of 16 is not a problem with the study, because the whole point of the study was to determine rates in adults as a function of age.

Once again, the absolute prevalence rate here is not the important bit. The authors started with a hypothesis, i.e. that autism prevalence rates have been rising over the last few decades. They then formulated an experiment to test that hypothesis which was to use a standardized diagnosis to a sample of the general population, then determine autism rates as a function of age.

So the study's exclusion of people under the age of 16 was not a problem, but rather an intentional design element of the study in order to answer the question asked. The question was not "What is the ASD prevalence rate?" The question was "Is the ASD prevalence rate in adults a function of age?"

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29. Derek R on May 5, 2011 10:39 AM writes...

Is there an online version available somewhere (such as an earlier draft of the paper)?

One important aspect would be the distribution of ages. If the average age of the participants was, say, 40 years old, then the researchers would have a hard time detecting a rise in autism rates, because they started rising about 25 years ago.

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30. Derek R on May 5, 2011 11:12 AM writes...

I think I found a link to a preliminary draft (pdf format):

http://www.natcen.ac.uk/media/665717/autism%20spectrum%20disorders%20research%20report.pdf

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31. MTK on May 5, 2011 11:42 AM writes...

Derek R,

I tried to explain the methodology in post #24.

They weighted the results of the tests from the 7403 respondents based on demographics as determined by the general population. This is a very common and accepted technique, so if one age group were under or over represented in the survey group that would be accounted for.

And why, for the love of pete, would they have hard time seeing a rise in rates if the avg. age was 40? In fact, they'd have an easier time using your logic, because they'd diagnose no one with ASD in the older subset.

The fact that the study did come to about a 1 in 100 rate amongst all adults regardless of age group is telling, IMO. While the absolute prevalence rate was not really the point, the fact that it's pretty close to the rate now says that the researchers probably used diagnostic and statistical methods consistent with that used in current childhood studies.

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32. Derek R on May 5, 2011 11:54 AM writes...

MTK,

If autism has been increasing steadily over the decades, then an average age of 40 would still show a change. However, it seems that autism has remained stable for many decades, then "mushroomed" in the last 25 years. So any study that omits a large chunk of the population born within 25 years, I think is working with weak data.

Also, if we assume that the autism rate is 1%, but diagnoses have ballooned recently, what is the cause of that surge? Have the test thresholds been changing over time, to result in more kids being diagnosed?

A very simple study would be apply the same test to people 25 years old and younger, to see if there has been an increase.

(BTW, I don't have an agenda in case you're wondering! )

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33. Jon on May 5, 2011 1:27 PM writes...

Derek,

I would re-emphasize what MTK stated: the authors weighted the population by UK region, age, and sex, so any over-/under-sampling of any subgroup in the study is corrected for.

If the report you linked is in fact the basis for the paper, then see Table 3.5, where it lists each age group in 10-year increments and shows how each age group was weighted. You are correct in that the younger groups tended to be under-sampled, but again, this was corrected by weighting.

However, because there were relatively few ASD diagnoses, the authors decided to group the respondents into 30-year age groups to determine ASD prevalence, with the youngest age group being 16-44. The authors note a slight (but statistically insignificant) decline in ASD prevalence with an increase in age (1.1% to 0.8%). See Table 2B. But even if this were significant, a 0.8-0.9% ASD rate in the 45+ year old population runs counter to the notion that there has been a recent explosion in ASD since current childhood rates are about 1%.

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34. Jon on May 5, 2011 1:30 PM writes...

Derek,

I meant to add that if you are still hung up on the prevalence in the

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35. Derek R on May 5, 2011 2:23 PM writes...

I looked at the paper again, and thought of two more problems.

1. Do ASD symptoms increase, decrease, or remain stable as a person reaches adulthood? To say that 1% of adults have ASD therefore 1% of kids will, sounds like an assumption. Simplistic example: 1% of adults have osteoporosis... does that mean that 1% of children have it?

2. An ASD test for a 40 year old will be different than a test for a 4 year old. Has anyone correlated the scores between the two types of tests? There might be a big difference. What if a 1% incidence for children now means a 5% incidence for adults in the future? (I guess that's related to my first point.)

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36. Derek R on May 5, 2011 3:57 PM writes...

Here's another interesting fact from the paper: they only tested people living in private households. So that would have actually selected against people with more severe forms of ASD:

"3.2.1 Overview of the sample design
The sample for APMS 2007 was designed to be representative of the population living in
private households (that is, people not living in communal establishments) in England.
People living in institutions are more likely than those living in private households to have
ASD, however this group was not covered in the survey reported on here and this should be
borne in mind when considering the survey’s account. At the time of the 2001 Census, 2%
of the English population aged 16 years or over were resident in a communal establishment.

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37. Jon on May 5, 2011 6:16 PM writes...

Derek,

The 1% ASD rate in children is not an assumption, it's based on empirical evidence as reported in several studies (ie., a commonly accepted approximation). So the fact that this study found adult rates to be practically the same supports the notion that ASD is not age-dependent. Additionally, had the study been expanded to the homeless and institutionalized (appropriately weighted of course), I'm guessing you'd find the adult ASD rates go up slightly, further evidence against the purported ASD rate "explosion."

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38. Derek R on May 5, 2011 7:20 PM writes...

If the explosion really is an illusion, there should be some research as to what failure of diagnostics methodology is responsible for the big ramp-up if ASD rates since 1985.

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39. Jon on May 5, 2011 8:15 PM writes...

If you do some research on the topic you'll find some answers on why ASD was under diagnosed in the past. I'm not an expert in the area, but a quick search led to a 2003 paper by Gurney et al. (Arch Pediatr Adolesc Med). They looked at prevalence in Minnesota children from 1981-2002, and found a 17-fold increase in rates between 1991 and 2002 alone. Their conclusion: "federal and state administrative changes in policy and law favoring better identification and reporting of autism are likely contributing factors to the prevalence increases and may imply that autism spectrum disorder has been underdiagnosed in the past." Apparently this is not an uncommon finding.

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40. luysii on May 5, 2011 8:49 PM writes...

Jon and Derek R -- please have a look at http://www.suite101.com/content/history-of-autism-in-the-dsm-a40664. I think you are talking past each other. Here's an abstract of what's there.

Autism spectrum disorder didn't exist prior to the release of DSM-IV (Diagnostic and Statistical Manual of the American Psychiatric Association 4th edition) in 1994.

The DSM-III (released in 1980) " and we finally see the inclusion of autism as a separate diagnostic category. At this point, there was only one autism designation and it was entitled infantile autism. There were only six characteristics listed and each of these six symptoms must be present in order for an individual to be diagnosed with infantile autism. Due to some controversy surrounding the descriptor infantile, this category was changed to autistic disorder in 1987." Notice how strict the criteria were for diagnosis.

To continue from the site. "The most recent complete release of the DSM, the DSM-IV, occurred in 1994. At this point, the category of pervasive developmental disorders and several subtypes were added. In addition to autistic disorder, a diagnosis could be made under the categories of Asperger’s Disorder, Rett’s Disorder, Childhood Disintegrative Disorder, and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS).

Besides the inclusion of four new subtypes, drastic changes were made to the criteria that needed to be met in order to receive a diagnosis of autistic disorder. The current release of the DSM has a list of 16 different symptoms used to describe autistic disorder and a patient only needs to exhibit six of the 16 to receive the diagnosis. This is in stark contrast to the language used in the 1980 release of the DSM-III."

So they couldn't diagnose ASD in 1980, because the diagnosis didn't exist. Also note how much looser the criteria are for diagnosis in 1994. This is the likely cause of the 'epidemic' of autism.

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41. Jon on May 6, 2011 9:09 AM writes...

luysii - thanks for the useful insight, this gets to the core of Derek R's last post.

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42. Derek R on May 6, 2011 11:12 AM writes...

Now all we need to do is apply, in a consistent way, the DSM-IV tests to a group of people born since 1980. Then we'll be able to confirm if high ASD rates are due to changes in testing.

However, to be pedantic about it, shouldn't the ASD rates have stabilized once everyone was using the DSM-IV diagnostics?

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43. Jon on May 6, 2011 4:01 PM writes...

I don't think "precision" is an attribute common to the field of psychiatry given the nature of neurocognative diseases (especially for a group of conditions that comprise ASD). On one hand the sprectrum wasn't defined until the mid-90's, on the other you have an initial lack of awareness on the part of pediatricians and parents. And then you have Wakefield's fraud initiated at the turn of the millenium, the only benefit of which was to raise Autism awareness among parents and researchers. The Brugha et al. paper - which applied DSM-IV criteria across all age bins - is just the latest to shine light on the "epidemic" issue. It seems that the conclusions are pretty consistent thus far.

But I don't see why this or another group of investigators couldn't run your study (if it hasn't already been done, that is). You should write them or submit a letter to the editor of the Archives of General Psychiatry requesting this specific analysis. This study isn't perfect, as I'm sure the investigators are aware, so I would think they'd be willing to address questions about their study.

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44. MTK on May 6, 2011 4:17 PM writes...

@42,

Not if DSM-IV, or any other standard, testing is being used more often now than before due to increased awareness.

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45. Jonadab on May 9, 2011 7:27 AM writes...

> what this study supports is the idea of an
> increase in diagnosis, not in the underlying
> condition.

Indeed.

I live in a city of eleven thousand people (albeit, not in the UK), and I am personally acquainted with three (3) children who are said to be autistic. None of them exhibit any of the traditional symptoms. They do not, for example, have any particular difficulty communicating with other children. (They tend to ignore their parents, but that could easily be chalked up to a completely unrelated epidemic.) Frankly, someone who didn't KNOW they are autistic could be excused for failing to notice their autism at all. Thirty years ago they certainly would not have been diagnosed with it.

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46. luysii on May 9, 2011 10:19 AM writes...

#45 Exactly -- see http://www.suite101.com/content/history-of-autism-in-the-dsm-a40664 (or #40 for for a synopsis) for why this is so.

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47. Matthew on May 20, 2011 5:08 PM writes...

1994 - DSM-IV drastically changes the definition of "autism", as outlined above. PDD-NOS is a wastebasket diagnosis. I've seen it used appropriately on occasion & misused often.

Parents of children with an accepted DSM-IV diagnosis could then use that dx to apply for SSI (supplemental security income), providing a financial incentive for diagnosis.

1997 - Significant amendments are added to the Individuals with Disabilities Education Act (IDEA) expanding the definition of disability to include children with developmental delays, including pervasive developmental disorders. This gave parents another incentive to get their child diagnosed, qualifying them for all sorts of extra services.

There are your reasons for the non-existent "epidemic." I'm not saying that children on the milder end of the autism spectrum don't deserve extra educational services or even SSI if their disability is profound enough. I'm just saying that there are strong incentives to seek diagnosis that weren't present until ~ 15 years ago, and the loose definition allowed in the DSM-IV (especially PDD-NOS) opened the floodgates.

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