Autism Information: Inside
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Autism is known to be highly heritable. Research done by some institutions seek to find a way for early and more accurate detection of autism similar to Rett syndrome. Instead of searching for one particular gene as the cause for autism, many of the studies tend to search for complex interactions between a number of genes.

A 2005 study done by the Duke Center for Human Genetics at Duke University finds some evidence that complex interactions between GABA (gamma aminobutyric acid) receptor genes might be part of the cause of autism. One of the functions of the GABA genes is to inhibit the nerve system from firing. The theory is that somehow GABA genes suffer damage of some kind, leading to an overwhelmed sensory system causing the characteristics or symptoms of autism.

Simon Baron-Cohen proposes a model for autism based in his empathising-systemising (E-S) theory. His team at the Autism Research center in Cambridge, UK, measured testosterone levels in the amniotic fluid of mothers while pregnant. This is presumed to reflect levels in the babies themselves. The team found that the babies with higher fetal testosterone levels had a smaller vocabulary and made eye contact less often when they were a year old.

His group has looked at the original 58 children again, at age four. The researchers found that the children with higher testosterone in the womb are less developed socially, and the interests of boys are more restricted than girls. The results are published in the Journal of Child Psychology and Psychiatry in a 2004 issue.

Baron-Cohen theorizes that high fetal testosterone levels push brain development towards an improved ability to see patterns and analyze systems. Males supposedly tend to be better at these tasks than females. But the high levels are thought to inhibit the development of communication and empathy, which are allegedly typical female skills.

However, there is still no demonstrable evidence that testosterone levels affect brain development or autism. Gender or bio determinism is a fashionable explanation for many human behaviors, but has been challenged by other professionals

Controversial research by Andrew Wakefield in the UK that was published in The Lancet in the February 1998 issue, dubbed the "Wakefield Study", suggested a possible link between autism and the MMR vaccine. The original research has come under criticism, largely due to an alleged conflict of interest on Wakefield's part. In March 2004, almost all of the paper's authors retracted its "interpretation" section, which claimed a potential link between pervasive developmental disorders and "possible environmental triggers".

Critics have claimed that Wakefield's study contains many obvious flaws, including an inability to recognize bias in his sample. In October 2005, a study by the respected Cochrane Library said, on the basis of 31 pieces of research into the possible side effects of MMR, that it found no association between MMR and autism. Several independent groups, including the National Academy of Sciences, have also conducted investigations and concluded that the evidence does not support a link.

One study by Gillberg and Heijbel in 1998 examining the prevalence of autism in children born in Sweden from 1975 to 1984 found no difference in the prevalence of autistic children born before the introduction of the MMR vaccine in Sweden and those born after the vaccine was introduced. Another study, conducted by Madsen and other researchers in 2002, studied all children born in Denmark from January 1991 through December 1998. There were a total of 537,303 children in the study; 440,655 of the children were vaccinated with MMR and 96,648 were not. The researchers did not find a higher risk of autism in the vaccinated than in the unvaccinated group of children.

Research in the U.S. has suggested a similar link between autism and the DPT vaccine, although this is not referenced. However, unlike early claims from Wakefield, it is doubtful that a large majority of autism cases would come from this vaccine. Despite all the evidence to the contrary, controversy surrounding autism and vaccines continues to this day, and many polls, such as the autism coach poll, which involved only 15 respondents, show vaccines as the most popular theory currently on the etiology of autism among parents of autistic children.

In a controversial article in June 2005, Robert F. Kennedy, Jr. described research suggesting that it is not the vaccines themselves, but a mercury-based preservative called thimerosal, used in some vaccine preparations (although not MMR), that may be a cause of autism. Kennedy argues that autism was first observed in children who were born around the time of introduction of thimerosal into mass-produced vaccines, and that the incidence of autism in the United States is well correlated with the amounts of thimerosal children receive during their first two years of life. However, the CDC has described a link between thimerosal and autism as 'unlikely'

In 1999 the Public Health Service (including the CDC, FDA, and NIH) recommended that thimerosal no longer be used in vaccine preparations. And while thimerosal is now utilized in only a very few childhood vaccines, it has not been established that autism rates have dropped significantly. The CDC and some medical organizations have repeatedly asserted that no available evidence supports a causal link between thimerosal and autism. Critics have in turn presented criticism of the CDC analyses that suggest deliberate bias in the CDC research.

For example, an analysis of autism rates by Madsen et al. in Demark noted that the incidence of autism remained fairly constant while thimerosal was being phased out and started to rise beginning in 1991, even after thimerosal was discontinued in 1992. Critics of this analysis point out that the methodology was biased. Critics of the Denmark data also point out a significant increase in autism rates among children whose childhood vaccines contained thimerosal. However, in Madsen et al.'s study, the amount of thimerosal in the vaccinations actually decreased while autism rates increased (specifically, during the period 1961–1970, infants had received a total of 400 µg of thimerosal by the age of 15 months, and during the period 1970–1992, infants had received a total of 250 µg of thimerosal at 10 months of age).

The California Department of Developmental Services (DDS), considered to have the best reporting system for autism in the US , has reported unprecedented decreases in new cases entering the system. The number of new cases went from 734 during the second quarter of 2005 to 678 new cases during the third quarter of 2005, a 7.5% decline in one quarter. Note that the total caseload handled by the state is still increasing, but the recent trend points to decreases in the caseload increase. For example, from the 2nd to the 3rd quarter of 2004, the caseload went from 25,020 to 25,769 (749 new cases). Between the 1st and 2nd quarter of 2004, the caseload increased from 24,297 to 25,020 (723 new cases). These variations have led to speculation that removal of thimerosal from vaccines in California is starting to pay off. Others point out they are unremarkable and may simply be an indication that the awareness curve is starting to level off, and that new cases should be expected to decrease to population growth levels (1.6% annual) eventually, probably within a decade or two. Caseload increase between 2004 and 2005 was about 10%

Dr. Bruno Bettelheim believed that autism was linked to early childhood trauma, and his work was highly influential for decades both in the medical and popular spheres. Parents, especially mothers, of autistic's were blamed for having caused their child's condition through the withholding of affection. Leo Kanner, who first described autism (Autistic disturbances of affective contact, 1943) originated the "refrigerator mother" hypothesis, which held that autism was at least partly caused by a lack of affection from the mother. Although Kanner eventually renounced the theory and apologized publicly, Bettelheim put an almost exclusive emphasis on it in both his medical and his popular books. These theories did nothing to address the fact that having more than one autistic child in a family is exceptional, not the rule. Treatments based on these theories failed to help autistic children, and after Bettelheim's death it came out that his reported rates of cure (around 85%) were found to be fraudulent.

Psychogenic theories in general have become increasingly unpopular, particularly since twin studies have shown that autism is highly heritable. Nevertheless, some case reports have found that deep institutional privation can result in "quasi-autistic" symptoms without the neuroanatomical differences. Other case reports have suggested that children predisposed genetically to autism can develop "autistic devices" in response to traumatic events such as the birth of a sibling

Susan Bryson has claimed that some autistic's have evidence of trauma to the brain stem in early development, and that a small portion of the thalidomide victims have become autistic. The victims' limbs were normal unless thalidomide use continued later in the pregnancy. The brain stem anomaly's most striking feature is inability to focus attention away from a stimulus in a short time like neurotypicals, as demonstrated in a psychological test.

Some people claim the inability to shift attention quickly interferes with the ability to read nonverbal language where fast attention shifts are needed (such as eye language), suggesting that being nonverbal is not a primary feature of autism. Strong and shiftless focus is, however, a benefit in some areas like science, programming, and advanced mathematics. This is supported by the monotropism hypothesis.

Dr. Bernard Rimland's influential research and his book Infantile Autism (1967) argued that autism was not caused by childhood trauma or abuse, but by damage to certain areas of the brain, particularly the reticular formation which associates present sensory input with memories of past experiences. Dr. Rimland is a foremost advocate of the theory that autism may be precipitated by mercury and heavy metal toxicity. He also is prominent in increasingly common claims of successful treatment of autism in children—particularly regarding improvements in ability to comprehend the spoken word—with the gluten-free, casein-free diet and mercury chelation therapy.

Others claim Dr. Bernard Rimland's methods alleviate the symptoms of heavy metal poisoning, but not autism. Curing heavy metal poisoning when it is present is a worthy goal (it helps with IQ and other learning difficulties as well as general health), but claiming a benefit for autism is a misrepresentation. Heavy metal poisoning may be more common among autistic's due to a severe metallothionein deficiency, but more evidence is needed to substantiate the idea that heavy metals cause autism. It is still being studied. The presence of heavy metals, particularly mercury, might make an autism diagnosis more likely, however.

A growing body of peer-reviewed studies published in mainstream journals has shown that many common diseases of previously unknown origin are caused by the presence of slowly acting viruses. For example, cervical cancer is caused by the human papilloma wart virus; some cases of liver cancer are caused by hepatitis C or B; Schizophrenia may be caused by Borna virus. Paul W. Ewald, among others, argues that the available data on the origin of autism is consistent with it being caused by a virus or infection. Alternatively, it was hypothesized that certain antibiotics rather than an infection may be associated with autism; that is, depending on certain conditions they could be either harmful or helpful

There has been an explosion worldwide in reported cases of autism over the last ten years, which is largely reminiscent of increases in the diagnosis of schizophrenia and multiple personality disorder in the twentieth century. This has brought rise to a number of different theories as to the nature of the sudden increase.

Epidemiologists argue that the rise in diagnoses in the United States is partly or entirely attributable to changes in diagnostic criteria, reclassifications, public awareness, and the incentive to receive federally mandated services. A widely cited study from the M.I.N.D. Institute in California (17 October 2002), claimed that the increase in autism is real, even after those complicating factors are accounted for (see reference in this section below).

Other researchers remain unconvinced, including Dr. Chris Johnson, a professor of pediatrics at the University of Texas Health Sciences Center at San Antonio and cochair of the American Academy of Pediatrics Autism Expert Panel, who says, "There is a chance we're seeing a true rise, but right now I don't think anybody can answer that question for sure."

The answer to this question has significant ramifications on the direction of research, since a real increase would focus more attention (and research funding) on the search for environmental factors, while little or no real increase would focus more attention to genetics. On the other hand, it is conceivable that certain environmental factors (vaccination, diet, societal changes) may have a particular impact on people with a specific genetic constitution. There is little public research on the effects of in vitro fertilization on the number of incidences of autism.

One of the more popular theories is that there is a connection between "geekdom" and autism. This is hinted, for instance, by a Wired Magazine article in 2001 entitled "The Geek Syndrome", which is a point argued by many in the autism rights movement.This article, many professionals assert, is just one example of the media's application of mental disease labels to what is actually variant normal behavior—they argue that shyness, lack of athletic ability or social skills, and intellectual interests, even when they seem unusual to others, are not in themselves signs of autism or Asperger's syndrome. Others assert that it is actually the medical profession which is applying mental disease labels to children who in the past would have simply been accepted as a little different or even labeled 'gifted'. See clinomorphism for further discussion of this issue.

Due to the recent publicity surrounding autism and autistic spectrum disorders, an increasing number of adults are choosing to seek diagnoses of high-functioning autism or Asperger's syndrome in light of symptoms they currently experience or experienced during childhood. Since the cause of autism is thought to be at least partly genetic, a proportion of these adults seek their own diagnosis specifically as follow-up to their children's diagnoses. Because autism falls into the pervasive developmental disorder category, strictly speaking, symptoms must have been present in a given patient before age seven in order to make a differential diagnosis.