Autism, or Autism Spectrum Disorder, is a neurodevelopmental condition that influences a person’s sensory processing, behaviour, communication, and interests. People on the spectrum have a higher amount of perceptual processing, which can present itself as things like hypersensitivity to noise, movement, and other stimuli (Foss-Feig at al., 2013; Mottron et al., 2006). It is considered a “spectrum” disorder because there is a lot of variation in how it can affect people with the condition, as well as how people experience it. People on the Autism spectrum may also need different levels of support (Autism Ontario; National Institute of Mental Health). 

 

While the exact cause of autism has not been discovered, it is known that there is a strong genetic component, as mediated by genetic mutations. However, there is no one “autism gene” that is mutated in every Autistic person; instead, there are about 100 genes that are linked to Autism (Zeliadt, 2020). Something that clearly shows the influence of genetics on Autism is twin studies, where the correlation between having Autism in both twins is determined. One meta-analysis (statistical analysis combining results of several other studies) of twin studies revealed that in identical twins, there is a high chance that both twins will have Autism (correlation of 0.98), while fraternal twins had a much lower correlation (0.53) (Tick et al., 2015). This suggests that genetics play a more important role in causing Autism than environmental effects because it is assumed that both identical and fraternal twins have same, or similar, environmental conditions. 

 

Environmental causes of Autism must not be dismissed, however. There are several studies showing that the age of mothers, fathers, or both parents, affects the incidence of children with Autism. Another factor that may have a cause in Autism is maternal physical and mental health during pregnancy (Karimi et al., 2017). Thus, it is likely that there is a complex interplay between several genetic and environmental factors.

 

Something that has been proven to not be a factor in causing Autism is vaccines. The study published in 1998 by Andrew Wakefield and colleagues suggesting that the MMR (measles, mumps, and rubella) vaccine causes Autism has been retracted because this statement was disproved in several other studies. Furthermore, it was found that Wakefield had financial interests in presenting this conclusion, causing him to falsify facts and misreport data from the study (Rao & Andrade, 2011). 

 

It is important to note that many studies about Autism tend to view it as a disease or disorder. In the Autistic community, this is colloquially known as the disease model. However, many Autistic individuals argue that ASD should actually be viewed as an “inherent and valuable part of the range of human variation” (Dyck & Russel, 2019) rather than a medical disorder. This gives rise to the concept of neurodiversity, which sees “neurodivergent” people (people with Autism, ADHD, and other learning and thinking differences) as being different, rather than having a disease. This view decreases the stigma around the aforementioned conditions (Rosen). 

 

Although there are several factors that are seen as having a role in causing Autism, there is still much to be learned about neurodivergent people and the way their brains work. In the meantime, it is important to recognize neurodivergent people as a valuable part of society, and to decrease the stigma around Autism and other neurodivergent conditions. 

 

 

References

 

Autism Ontario. About Autism. https://www.autismontario.com/about-autism

 

Dyck E. & Russell G. (2020) Challenging Psychiatric Classification: Healthy Autistic Diversity and the Neurodiversity

Movement. In: Taylor S., Brumby A. (eds) Healthy Minds in the Twentieth Century. Mental Health in Historical Perspective. Palgrave Macmillan, Cham. https://doi.org/10.1007/978-3-030-27275-3_8

 

Foss-Heig, J., Tadin, D., Schauder, K.B., Cascio, C.J. (2013). A Substantial and Unexpected Enhancement of Motion

Perception in Autism. Journal of Neuroscience, 33(19), https://doi.org/10.1523/JNEUROSCI.1608-12.2013

 

Karimi P., Kamali E., Mousavi, S.M., Karahmadi, M. (2017). Environmental factors influencing the risk of autism.

Journal in Research in Medical Sciences. 22(27). doi:10.4103/1735-1995.200272

 

Mottron, L., Dawson, M., Soulières, I., Hubert, B., Burack, J. (2006). Enhanced Perceptual Functioning in Autism: An

Update, and Eight Principles of Autistic Perception. Journal of Autism and Developmental Disorders, 36(1), doi:10.1007/s10803-005-0040-7

 

National Institute of Mental Health. Autism Spectrum Disorder. https://www.nimh.nih.gov/health/topics/autism-

spectrum-disorders-asd/index.shtml

 

Rosen, P. Neurodiversity: What You Need to Know. Understood. https://www.understood.org/en/friends-

feelings/empowering-your-child/building-on-strengths/neurodiversity-what-you-need-to-know

 

Sathyanarayana Rao, T.S & Andrade C. (2011). The MMR vaccine and autism: Sensation, refutation, retraction, and

fraud.Indian Journal of Psychiatry. 53(22). doi: 10.4103/0019-5545.82529

 

Tick, B., Bolton, P., Happé, F., Rutter, M., Riisdiik, F. (2015). Heritability of autism spectrum disorders: a meta-

analysis of twin studies. Journal of Child Psychology and Psychiatry. 57(5). https://doi.org/10.1111/jcpp.12499

Zeliadt, N. (2020, September 3). Autism genetics, explained. Spectrum News.

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