Monday, May 29, 2006

Cultural Construct Misconceptions

Readers might see this entry as entirely theoretical. Well, I find concepts and ideas fascinating and that's why I'm writing about this, so bare with me. Also, I think this particular concept is in fact useful.

I get the feeling there are several misconceptions about the notion of autism as a cultural construct, and I hope to address them with a list of points and a follow-up example. Some of these misconceptions are aspects of the theory that I have been confused about myself.


  • Saying that autism is a cultural construct is simply an ideology.

    Actually, a cultural construct or social construct theory about an entity is a scientific theory that is falsifiable. It should not be confused with Neurodiversity, which is an ideology.

  • Claiming that autism is a cultural construct is equivalent to claiming that autism is not "real" - that it does not exist, or that it's not useful.

    No. Cultural constructs are very real and useful. Language is a cultural construct. Countries are a cultural construct. Money is a cultural construct. Believe me, I'm not about to cash all my savings and throw them away because money is a cultural construct. The purpose of cultural constructionism is to understand the usefulness of cultural constructs.

  • It means that people cannot identify as autistic.

    That's not correct. See the Example section below.

  • It means there are no differences between autistics and non-autistics.

    The fact that differences between autistics and non-autistics can be found is not surprising. Differences can probably be found across any behavioral spectrum, regardless of where the spectrum is divided. Differences can be found between men and women; between races; between any two groups of people, in fact. These differences are often found to occur 'in average' (i.e. they can't be generalized), but this is not a requirement of cultural construct theory.

  • It means autism does not have a cause or a treatment.

    Again, this is not correct. Cultural constructs may have underlying mechanisms which are not only cultural, including but not limited to genetic mechanisms. See the Example section below.

  • Cultural construct theory only applies to 'mild' cases of autism.

    There is no such limit imposed by cultural construct theory, and there is no non-cultural way to define such a boundary.

  • Cultural construct theory does not have a practical application.

    I think cultural construct theory can help explain the "autism epidemic" and help decipher some of the causes of autism. Current thinking of autism as an identifiable "brain disease" is leading nowhere. The example below provides a model which could be helpful in this regard.



Example

A straightforward cultural construct is short stature. Consider how short stature is defined. Should only the bottom percentile of the population in height be considered short? How about the bottom 5%? 10%?

Is it real? Of course. Does it have causes? Yes, it probably has many causes, including genetics. Is it pathological? In some cases it probably is. Is pathology determined by severity? Not necessarily. Is it treatable? Human Growth Hormone (HGH) can help - whether it's advisable to use it is debatable. Can people identify as short? Evidently. Is it absolute? "Short" surely has a different meaning in different cultures. Can it be a burden and lead to suffering? I'm sure it can.

A more relevant example of a cultural construct is mental retardation. Consider how the questions above are answered in regards to this construct.

Further Reading

- Timimi, S. Taylor, E. ADHD is best understood as a cultural construct. The British Journal of Psychiatry (2004).

- Timimi, S. Diagnosis of autism: Current epidemic has social context. BMJ (2004).

Thursday, May 25, 2006

Pica and Heavy Metal Toxicity

Developmentally delayed children tend to have Pica. Pica can result in higher blood lead levels, particularly if the child is eating paint chips. I was wondering what the impact of Pica might be on any studies that attempt to correlate heavy metal toxicity with autism.

Some references follow.

Accardo et al (1988)

Shannon et al (1996)

Cohen et al (1976)

My son does like to chew on paper sometimes. He likes to eat all kinds of things he finds on the floor. Strangely, he's fussy about actual food. No paint chips, however, as far as I know. I will discuss this with his pediatrician in any case.

Wednesday, May 24, 2006

Do Murderers Deserve Our Sympathy?

Murders do not occur in a vacuum. In some societies murder occurs more often than in others. It's always possible for murderers to find some kind of justification for their crime. Maybe they were experiencing economic hardship. Maybe they were abused as children. Maybe they had some kind of "mental illness". Maybe they did not receive enough support and services.

But the role of society in making murder more likely does not constitute a justification for murder. Murderers do not deserve our sympathy and should be punished regardless of circumstances.

And people realize this for the most part. When parents murder their non-disabled children, there's seldom any sympathy for the murderers. This is true regardless of any hardships the murderers might have been experiencing. Sentences are generally harsh. And there's little to no outcry about such sentences.

But it's different with disabled children. And I can't help but conclude this is because the disabled victim is considered to be less than human - perhaps better dead than disabled.

And make no mistake. It's not autism which caused Karen McCarron (reputedly a curebie mom) to snap. It was the negative discourse about autism which contributed to her state of mind. It's organizations like Autism Speaks with videos such as Autism Every Day. They have sent a message (and continue to do so as I write this) to the effect that it's unremarkable for parents of autistics to be thinking about killing their autistic children.

Things don't have to be this way, as evidenced by all the parents writing about acceptance at Autism Hub, and by the parents of Rett girls, who apparently don't spend their time whining about services and the mostly self-imposed difficulties of raising autistic children.

I'm not one to believe in fate or purpose. But I'm willing to consider that Katie's death might have fulfilled a purpose in a sense. Perhaps it will help people realize that "if we believe absurdities, we shall commit atrocities", as Autism Diva points out.

In Memoriam - Katherine "Katie" McCarron

Thursday, May 18, 2006

The Pragmatic Case Against Eugenics

Allow me to list the terms that should be used to properly refer to prenatal testing of autism and other genotypes.

Genocide.- "The systematic killing of substantial numbers of people on the basis of ethnicity, religion, political opinion, social status, or other particularity." (Wiktionary)

Eugenics.- "A social philosophy which advocates the improvement of human hereditary qualities through selective breeding. See natural selection." (Wiktionary)

Eugenicists prefer to dance around these terms in favor of euphemisms such as "reproductive choice". But this debate is not about a woman's right to choose to give birth. It's about the potential to choose which types of children are born based on their genetic makeup. Breeding humans in this manner is no one's right, and should never have become an option.

This is a moral issue primarily, but it is also a pragmatic issue. Let's think about the practical implications of artificially selecting human beings.

I don't just mean that it would be a bad idea to abort a potential Bill Gates. This example is easy to grasp, but it only represents the tip of the iceberg. And eugenicists will no doubt try to work around this problem by choosing specific characteristics that make people like Bill Gates successful (e.g. abort only those who are "low functioning" - for the time being).

The main problem with eugenics is that it's a potentially catastrophic experiment involving the entire human race. It presumes that humans are capable (without any prior experience) of replacing nature in its task of natural selection and evolution. It presumes that we know which traits are desirable and which aren't. It presumes that we can anticipate our future needs, and that we can ensure the survival of the species under varying environmental circumstances.

Human diversity is not a politically correct description of human deficiencies. It's a necessary part of our species. A civilization where everyone is a talented salesperson could not possibly function; nor could a civilization where everyone is a scientist or an engineer. There is a term from evolutionary theory for this equilibrium. It's called balanced polymorphism or disruptive selection. This is the mechanism that ensures the existence of genetic diversity within a species, and naturally leads to the existence of "fringe" phenotypes.

Autism is particularly problematic in regards to eugenics. It is likely that autism results from the combination of multiple alleles, perhaps 3, perhaps 100. Phenotypes such as autism and homosexuality have a reproductive disadvantage, but it is clear that the individual alleles that make up the corresponding genotypes cannot be reproductively disadvantageous. If parents start to abort babies with specific allele combinations, then the frequency of each individual allele will likely increase, as parents attempt to reproduce again. It will be increasingly difficult to conceive children who are not autistic.

The debate over the ethics of eugenics relates also to the debate over the ethics of cloning. Imagine a future where parents prefer to clone celebrities instead of conceiving their own biological children. It would lead to the same outcome: catastrophic collapse of the species.

Finally, I must point out that while they may try to exterminate our kind, we will not just disappear quietly into the night. Think about the pragmatics of that.

Thursday, May 11, 2006

Real Downward Trends in Thimerosal-Autism Web Traffic Following Removal of Thimerosal from Vaccines

Background. According to the FDA, “since 2001, all vaccines manufactured for the U.S. market and routinely recommended for children < 6 years of age have contained no thimerosal or only trace amounts (< 1 microgram of mercury per dose remaining from the manufacturing process), with the exception of inactivated influenza vaccine.” It should be noted that influenza vaccination is voluntary. The incidence of autism has failed to drop as a result of removal of thimerosal from vaccines, despite erroneous claims to the contrary. We are not aware of any studies (or science blogs) that have attempted to determine if removal of thimerosal has had an effect in the popularity of the thimerosal hypothesis of autism instead. (Drops in VAERS reporting have been noted, however).

Methods. Three groups of websites were compared using Alexa.com web traffic data. Group 1 (the control group) consisted of 3 top autism websites found through a Google search on the search phrase “autism” and verification of reach through Alexa.com. Group 2 consisted of 3 autism websites well-known for their focus on neurodiversity and/or acceptance. Group 3 consisted of 3 autism websites well-known for their focus on the thimerosal hypothesis.

Results. The following tables summarize our findings. Data was obtained on 05/10/2006. Reach refers to number of unique visitors. Total reach change is calculated as a weighed average.

Table 1: Traffic trends of top "autism" sites.
Website3-month Reach Per Million3-month Reach Change
autism-society.org11+49%
autism.org8.15+46%
autismwebsite.com5.5+26%
Totals24.65+42.88%


Table 2: Traffic trends of top neurodiversity/acceptance sites.
Website3-month Reach Per Million3-month Reach Change
kevinleitch.co.uk27+69%
neurodiversity.com8.1+391%
autistics.org4.95+111%
Totals40.05+139.31%


Table 3: Traffic trends of top autism sites that promote the thimerosal hypothesis.
Website3-month Reach Per Million3-month Reach Change
generationrescue.org1.2-8%
safeminds.org0.05-86%
evidenceofharm.com0.05-80%
Totals1.3-13.77%


Conclusions. Thimerosal-autism web traffic is quickly imploding into oblivion, whereas autism acceptance traffic is clearly thriving. A surprising finding is that top neurodiversity related sites currently have more web presence, in average, than top autism sites that can be easily found by typing “autism” in Google. And the gap will continue to widen. Kevin Leitch is credited with driving most of the current traffic. The largest portion of traffic growth is currently experienced by Neurodiversity.com. This is indicative of a rapid paradigm shift away from the disease construct of autism. Researchers and the media would do well to take note of this. We also found that Autism-hub.co.uk has a reach of 11 with a 3-month reach change of +4,300%, but we have excluded it from the analysis because it’s a new website. We were unable to verify a prior claim by Handley that neurodiversity parents are “the minority of a minority of a minority”. Best Jr. had previously asked “How many parents do you think are that stoned that they would buy into something so absurd?” Evidently, many do, without being “stoned”. We further hypothesize that “Rescue Angel” Best Jr. has inadvertently contributed to the collapse of the thimerosal-autism worldview with his many writings. Geier & Geier (2006) attempted to argue that a correlation between autism incidence and thimerosal existed after removal of the same. Unfortunately, several fatal errors were pointed out to Geier & Geier, who subsequently requested data from California DDS to see if they could still substantiate their findings. They later backed down for reasons we can only speculate about. Shattuck (2006) was published shortly afterwards, showing that a good portion of the increase in diagnoses of autism can be attributed to diagnostic substitution. A prior paper by Geier & Geier on the link between thimerosal dose per child and autism prevalence has been shown to have unusual flaws. Geier & Geier are also known for their promotion of a chemical castration agent as a treatment for autism. In addition to this, a full retraction from David Kirby is expected by early 2007. Not surprisingly, the web presence of Evidenceofharm.com has all but disappeared. As we write this, the Amazon.com sales rank of “Evidence of Harm” is in free fall, dropping at a rate of 7-29% every day. A much publicized new website by Handley, Putchildrenfirst.org, was already noted by Abfh to be “less popular than vampire hobbit porn”. It is clear that the main proponents of the thimerosal hypothesis must be well aware of the rapid collapse of their promoted worldview.

Friday, May 05, 2006

Autism "Missed" Often, Even Today

Blaxill (2002) introduced the notion that there is no "hidden horde" of adult autistics. Blaxill's letter was already dissected by Kathleen Seidel in Reflections on the "Hidden Horde". Autism bloggers might also recall Mike Stanton's possible finding of a "hidden horde" in the UK.

What I want to focus on here is a specific type of claim put forth by Blaxill:

Nylander and Gillberg screened adult psychiatric outpatients for evidence of undiagnosed autistic spectrum disorders. This population had not been screened for autism previously. The authors hypothesized that they would find high rates of undiagnosed autism. The screening procedure located 19 adults with autistic spectrum disorders who had not received a prior diagnosis. However, the prevalence in this group was only 2.7 per 10000, a finding that provides little support for a hidden horde hypothesis. The authors note this point reluctantly, claiming that the observed prevalences "should be regarded as an absolute minimum."


Blaxill refers to Nylander & Gillberg (2001). The authors correctly qualify the "absolute minimum prevalence". Every autistic adult would not be expected to be a psychiatric out-patient, as defined in this study. But we can extrapolate. The authors find that 1.44% of these patients had "definite ASD". Now consider that the prevalence of psychiatric disorder in adults varies considerably between 10% and 20%. This would seem to result in a prevalence of 14 to 29 in 10,000, from this population alone.

Note also how Blaxill fails to mention that 89.5% of all autistics found by Nylander & Gillberg were previously "missed".

Scharin & Hellstrom (2004) have found that adult psychiatry does not recognize disorders in the patient population by the frequency the disorders presumably appear.

Consider also Stahlberg et al (2004), which finds that 30% of adult patients with ADHD had comorbid ASD. As of 2006, the prevalence of ADHD in adults in the US is 4.2% [ref]. If Stahlberg's sample is representative, the resulting prevalence of ASD is 126 in 10,000, from this population alone. This is clearly a scandalous result.

Bajerot et al (2001) found that 20% of OCD subjects had "autistic traits" and suggested that OCD is related to HFA and Asperger's. The prevalence of OCD in adults is around 4% [ref]. Putting these numbers together we come up with an ASD prevalence of around 80 in 10,000, from this population alone.

So far we have not even considered the institutionalized population. An early finding by Shah et al (1982) was that 38% of the adult population in a mental handicap hospital had behaviors consistent with autism. A similar result was obtained by La Malfa et al (2004) in an Italian population with intellectual disabilities. Before the study, only 7.8% were recognized as having PDD. Prevalence in the population with intellectual disabilities varies widely from 3% to 50%, according to de Bildt et al (2005). Considering that the prevalence of mental retardation is about 1%, a 38% proportion of ASD in this population would result in an ASD-MR prevalence of 38 in 10,000.

Autism is missed frequently in many populations. For example, among those with bipolar disorder, the prevalence of ASD is anywhere from 8% to 62% [ref]. It is about 32% in the population with epilepsy [ref]. (The prevalence of epilepsy is 0.5% to 1%). ASD affects about two thirds of people with Tourette Disorder [ref]. It is found in anywhere from 10% to 14% of the population with learning disabilities [ref][ref]. (The prevalence of learning disability is around 5% or 6%).

To contrast, note that the current California DDS recognition of autism in the population with epilepsy is about 4%, and 7% in the population with mental retardation. In other words, the prevalence of autism in California has nowhere to go but up.

No studies to date have looked at the total population prevalence of ASD in adults, but one comes close. Baron-Cohen et al (2001) assessed a control group with the Autism-Spectrum Quotient (AQ). It found that 2% scored higher than 32. The study mentions that after an interview, 7 of 11 previously undiagnosed high-scorers met threshold criteria for a DSM-IV diagnosis. It is also known that 20% of autistics are missed by the AQ. Putting these numbers together we come up with a prevalence of 159 in 10,000 for the non-institutionalized population of adults. The 2% finding should be taken with a grain of salt, as the control group size is only 174. But note the study was replicated in Japan by Kurita et al (2005) who found the proportion of high scorers to be 3% in a control group of 215 individuals.

[Errata: The best replication of Baron-Cohen et al (2001) is actually Wakabayashi et al (2004), with a control group of "normal adults" of size 194 and another control group of university students of size 1050. They found that 3% of individuals in both control groups scored more than 33.]

Baron-Cohen et al (2001) also found that scientists (including mathematicians) scored significantly higher than controls, as did the group of Mathematics Olympiad winners. I wonder if these qualify as "geeks who got lucky", which is the other theory Blaxill is fond of.

If these prevalence numbers in adults seem high, consider Posserud et al (2006) who found that 2.7% of children in the 7-9 cohort were high scorers in the ASSQ. This study also documents what I interpret as parent unwillingness to have a child labeled autistic.

So what is the true prevalence of ASD, after all relevant populations are screened? Is it 200 in 10,000 perhaps? Frankly, this question in unanswerable. A diagnosis of autism, to date, is inherently subjective. It's not only the criteria that matters, but also how the evaluator understands and interprets the criteria. Even when more systematic instruments are used, scoring each item is a subjective exercise, and threshold scores are either arbitrary or selected from a prior subjective basis. To take an example, Posserud el al (2006) finds that 2.7% of children score in the 97.3 percentile of the ASSQ. He could very well find that 5% of children are in the 95 percentile. Why is one boundary better than the other?

Timimi (2004) makes a good case about the subjectivity of an autism diagnosis. Other parents might also find some of Timimi's remarks encouraging:

In my clinical practice I often come across children and adolescents who are labeled autistic. When I focus on their abilities I often find much about them that does not fit the autistic discourse. Once I reopen the question of diagnosis many adolescents ask me to officially "undiagnose" them, which their parents are usually very pleased about.


Summary

Blaxill should recognize that his "hidden horde" device is of little value at this point. The prevalence of autism in adults is likely about as high as that found in children. Autism is apparently often "missed" in many populations and is only identified after exhaustive screening. Finally, it is important to realize that a diagnosis of autism is not medical, but subjective.

Joseph, father of autistic child

Monday, May 01, 2006

Preliminary Evidence Of Higher Reproduction Rates in Autistic Families

In Autism, Genetics and Evolution and in the comments section of one of Wade's blog entries, Ian Parker makes some good points about the genetics of autism.

Autism is known to be extremely heritable. It is perhaps the most heritable of all psychiatric disorders. It is about as heritable as intelligence and a lot more heritable than personality. Even though autism is not 100% heritable, no behavior or skill is known to be 100% heritable or anything close to that.

Given the low concordance of autism in siblings and fraternal twins compared to the concordance in identical twins, it is likely that autism results from the combination of a number of alleles, 3 to 15 or even more according to researchers. Since the prevalence of ASD is somewhat high (and I'd argue the current prevalence is still an underestimate) it follows that the frequency of most of the alleles that result in autism must be relatively high.

Ian Parker asks why the frequency of these alleles remains high. Even if only 1% of individuals with one of these alleles became autistic, and assuming that autistics procreate much less often than the average person (which I believe is an undisputed assumption), then the frequency of the allele in question should gradually drop until it is close to zero (or whatever can be maintained through new mutations and limited inheritance), unless non-autistic individuals with the allele reproduce more often than the average individual.

The alleles that result in autism must therefore have a slight reproductive advantage by themselves, and be reproductively disadvantageous when combined.

A follow-up question is why alleles that are reproductively advantageous don't have a frequency that gradually increases until it reaches 100%. Obviously, if all autism alleles reached a frequency of 100%, then nearly every person in the planet would be autistic. So there has to be a sort of frequency equilibrium for each autism allele.

It also follows from the above that the frequency of slightly disadvantageous alleles can be high and stable.

I hypothesize that frequency equilibrium applies to alleles associated with most other spectrum disorders in the field of psychiatry. It also contributes significantly to the huge diversity of human behavior, and explains seemingly paradoxical combinations of creativity, intelligence and neurological impairment.

There are ways to test this hypothesis. The alleles associated with autism can be mapped, and reproduction rates of non-autistic individuals with these alleles can be measured.

For the time being, let us consider the reproduction rates in the families of autistics, taking into account that parents of autistics are usually non-autistic.

I will use data from Table 2 of the US Census Report for 2003. This gives 0.89 children per family, 1.82 children per family with at least one child, and 2.46 children per family with at least two children. (I assume the number of children per family with at least 4 children is 4.25, and I have verified that variations in this number don't produce large errors).

Note that these numbers do not vary a lot from state to state, according to a 2000 Census table. It also seems these proportions have not changed much since 1994.

Now consider Ghaziuddin (2005) which examined 58 subjects with AS, and found that they had a total of 64 siblings. This gives a proportion of 2.1 children per family with at least one AS child.

See also Deykin et al (1979) which is a somewhat older paper. It finds a proportion of 3.18 children per family with at least 2 children. Based on the 1980 data found in the 1994 Census report, I estimate the proportion of children in households with at least 2 children at 2.81 in 1980.

Piven et al (1990) results in a proportion of 2.81 children per family, but it is unclear if the sample is complete, and the authors only looked at adult autistics and their siblings.

By themselves, these findings are not statistically significant, but taken together they might be indicative of a trend. Unfortunately, no studies have looked at this question specifically, so there is little to go on. (I have contacted some authors of such studies but they have not been able to provide any additional useful info so far).

There are some additional caveats:


  • Census data looks at all children under 18. Autism studies look at children diagnosed with autism, which rules out very young children, but at the same time could result in a youth bias. Research specifically looking into this question would find control probands matched by age.
  • The autistic child in a family likely reduces the 2nd generation reproduction rates in that family. This is not relevant to the analysis, however, as the number of families with autistic alleles is probably much larger than the number of families that have an autistic child.
  • There could easily be sociological reasons to explain a higher number of children in families where one child has been diagnosed with a psychiatric disorder. But this could also work in the opposite direction.
  • It is not necessary for non-autistics with autistic alleles to have a preference to procreate. It might be sufficient that they form families more often.


Conclusions

Autism alleles are likely advantageous by themselves, but reproductively disadvantageous when combined. This results in a frequency equilibrium for each of the alleles. The frequency of most autism alleles is likely high and relatively stable. Most autism alleles should thus not be described as "disease genes". This has some implications on how researchers should look for autism loci.

There is an open question as to whether autistic families reproduce more often than average. Additionally, research on the reproduction rates of individuals with specific alleles could be carried out.

Finally, this analysis shows that eugenics is pragmatically misguided. If combinations of alleles that have a high likelihood of resulting in autism are identified, and parents abort pregnancies based on this information, it is likely that the frequency of all autism alleles will increase (as parents may simply attempt to procreate again).