After autism was identified in 1943, numerous studies have been carried out to discover its pattern of signs and symptoms, causes, and also factors that trigger it. Due to the broadness of the characteristics of autism, the term of autism has changed to Autism Spectrum Disorders (ASD) (Berg 2009, p.14). Autism spectrum disorders are defined as developmental disabilities, which include classic autism, Asperger’s disorder and other specific conditions that can be grouped with it by the Center for Disease Control and Prevention in the US (Berg 2009, p.14). Derived from the definition, children that are autistic, have disabilities in their social and cognitive behaviour, affection and communication. Berg (2009, p.14) claims that “The severity of the condition varies greatly, as does the exact constellation of symptom”.
What are the definite causes of autism? For many years scientists have been attempting to obtain the best answer of what causes autism. They come up with results, hypothesis, speculations, some of which are valid, but yet appear to be flawed and incomplete. For instance, because it usually occurs after a child has received vaccination, some scientists have stated that vaccine is the cause of autism even though at this present time, they still cannot provide the exact evidence. On the contrary, economists from the Cornell University, who carried out a study on autism, presented their controversial research result to public and clearly stated that watching TV is the cause of autism (Easterbrook 2006, p.1-3).
Recently, a new paradigm on autism has arisen and appears to have the closest answer to what causes autism, which is stated by the Commonwealth research institute’s president, Michael Lerner (Berg 2009, p.16). He explained that “This hypothesis proposes a complex interaction of genes and environmental exposures, possibly during a critical window in neurodevelopment. No single substance would necessarily be the trigger; rather, a range of exposures, possibly in combination could be involved”. I believe it is quite difficult to define one solely factor that cause autism, because it seems that every factor has its own role. This new paradigm, perhaps, has the potential to explain why autism occurred and also it clarifies the relationship among factors which previously assumed by the scientists as the cause of autism. Related to the question of what cause autism and the new paradigm, explained by Lerner, this paper essentially aims to discuss the causes of autism based on a review of several articles which present causes of autism from a different point of view and backgrounds.
The Early Assumptions of What Causes Autism
Prompted by the complicated traits of this disease, scientists have also scrutinized genetics, neurobiology and most of all, vaccines. People believed studies that correlated the figures on vaccination given to children and the figures for autism, which at that moment appeared to be very logical and interrelated. Berg (2009, p.15) explains that “The case against vaccines is sometimes based on the presence of mercury in thimerosal, a compound used as a preservative in some vaccines”. Research proved that mercury has an effect on the brain, causing brain damage, which potentially can cause autism. Thus, if a child is vaccinated, he or she is at risk of becoming autistic.
The long debate about vaccine and autism was not only because of thimerosal, but also the substances in vaccines. Berg (2009, p.15) stated that “One CDC-funded study has also considered the possibility that the measles virus in the MMR vaccine might lead to autism by causing a persistent intestinal measles infection”. The thimerosal issue and the study about MMR somehow converge into the idea that vaccination is causing autism.
Michael Cuccaro, a psychiatrist from Duke University specializing in autism, stated that “It was thought we could identify the causes if we could understand those connections, but we’re still left searching for causes. There was a missing piece of the puzzle, which was the environment.” (Cuccaro 2004 quoted in Parsell 2004, p.311). One interesting theory that appeared to be supported by this statement is that autism may be caused by something in the environment. This is a similar statement which also provoked the Cornell Study (Easterbrook 2006, p.1).
Researchers from Cornell University proved that autism increased in areas that also have a high frequency of TV cable viewing. The researchers analyzed the growth of cable TV access and autism rates in a 17 year period in California and Pennsylvania and they concluded that the approximate 17 percent increase in autism in both areas was due to the increase in the viewing of cable TV. Furthermore, supported by the studies carried out by the Bureau of Labor Statistics on behavior, the study also found that in counties that have high precipitation the incidents of autism are high as well.
However, it was difficult for other scientists to admit that the Cornell study had traced new clue, that widespread autism occurrence was a consequence of an excessive exposure from certain objects on children. Objects in the environment that could harm children and cause autism could be toys that made of specific materials which contain dangerous chemical substances, or the clean water, with poor quality, that they consume daily. But in Cornell’s case the specific object is TV, and they think TV viewing might be the answer. The researchers, who are economists, were accused that they have disregarded essential factors that can cause autism and the rise in autism incidents. As stated by Wallis (2006, p.1-2), the measurement used in the research was wild and indirect because the data were weather reports and subscriptions to cable TV. Furthermore, the fact that the researchers ignored the need for an exact measurement on TV viewing frequency, led Wallis to call the results “oddly definitive conclusions” (Wallis 2006, p.2).
In terms of environment, scientists also included fetal or the womb environment during pregnancy rather than postnatal environment solely. A pediatric neurologist, Zimmerman, thinks that the contribution from the environment influences the fetal development by disturbing its normal growth and may end up, causing autism (Parsell 2004, p.311). For instance, Parsell (2004, p.311) mentioned Beth Crowell, a mother of triplet autistic children, as an example of the possibility that autism can be triggered since pregnancy. Crowell strongly believes that terbutaline, “a drug she had taken during pregnancy”, may have caused her children to become autistic. Her claim was considered as reasonable because an investigation carried out by
researchers has shown that there is a connection between terbutaline and the incidence of autism. However, Connor stated the alteration of fetus neurodevelopment which may lead to autism may also be triggered by factors derived from the pregnant mother herself and the most possible factor is hormones (Connor 2004 in Parsell 2004, p.312).
Interactions of the Previous Causes of Autism; the New Model of Autism
As has been mentioned formerly, a new model of how to understand the causes of autism recently has brought a new perspective. Julie Daniels, an assistant professor at the University of North Carolina Gilling School of Global Public Health, wrote a statement published as an editorial in one of the health journals, “There are probably many combinations of genes and environmental factors that contribute to the constellation of autistic traits” (Daniels 2006 quoted in Berg 2009, p.16). Based on her statement and cases of autism that occurred and were brought up in the media, I believe that there are many factors which interact and become the main cause for a child to become autistic. Furthermore, exposures from specific substances from the environment, whether it was during the pregnancy period or after the birth, could be the factors that trigger the onset of autism.
Arguments among scientists on determining the precise cause of autism are supposed to be settled now. Instead of debating the old theories of what causes autism, they now should instigate studies in order to better comprehend the association of all factors that contribute to autism and the explanation why autism incidents are seemingly increasing. However, as there are always differences in every case of autism, which are diverse signs, symptoms, degrees, certainly there are also specific causes of which in many cases related only to the specific case. This might be an obstacle for scientists to reveal the exact interactions of each factor, whether it is the main cause or a trigger.
In conclusion, although currently scientists have identified many factors that trigger or cause autism, still, to construct them solidly as the definite cause is unfeasible. There is no distinctive or trivial factor in the pieces of the autism puzzle, all of them should be considered and treated as if they are defining. Furthermore, the new paradigm which explains that there are interactions between environment and genes disorders on autistic child, hopefully, will encourage scientists to completely generate an advanced concept of autism.
Allen, Arthur. 2005,’ Sticking Up for Thimerosal’, retrieved 28 July 2009, <http://www.slate.com/id/2123647/>.
Berg, Rebecca. 2009, ‘Autism-An Environmental Health Issues After All?’, Journal of Environmental Health Vol. 71 Number 10, June, p.14-18. Available: http://proquest_1732150551.pdf
Christakis, D.A., Zimmerman, F.J., DiGiuseppe, D.L., & McCarty, C.A. 2004, ‘Early Television Exposure and Subsequent Attentional Problems in Children’, Pediatrics Vol. 113, April, pp. 708-713.
Easterbrook, G. 2006, ‘TV Really Might Cause Autism. A Slate exclusive: findings from a new Cornell study, retrieved 22 July 2009, <http://www.slate.com/id/2151538>.
Parsell, Diana. 2004, ‘Assault on Autism’, Science News. Vol. 166, Iss. 20, November, p. 311-312.
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