By David Martin, B.A.
Key Takeaways
Navigating the history of autism and when it was first regarded as a distinct condition
Describing some common myths and misconceptions associated with the condition
Exploring the reason behind the ever-increasing presence of autism in modern times
Using an epidemiological perspective to rationalize autism’s increasing rate
A Brief History
Autism, otherwise known as autism spectrum disorder (ASD), as a separate diagnosis, was first described in 1943 by a child psychologist by the name of Leo Kanner. Kanner had observed that some children exhibited aloofness, repetitive behaviors, and social communication challenges compared to other children in the same age group. In 2000, legislation in the form of the Children’s Health Act of 2000 was officially ratified to monitor and keep track of children who exhibited ASD symptoms throughout the United States. It was found that children born in 2016 were 1.6 times as likely to be identified as exhibiting autistic traits than children born in 2012 by 48 months of age (see diagram below). But what could explain this increasing rate of the condition?
Myths and Misconceptions
First, it is helpful to explore some common myths and stereotypes regarding the origin of ASD, as this will help alleviate some misconceptions regarding the condition’s spread. It was a commonly held belief that certain vaccines, such as the measles, mumps, and rubella (MMR) vaccine, were the perpetrators of the recent rise in autism diagnoses in young children. A 1998 study purported that the vaccine did contribute to the increasing prevalence rate of autism, which led to fear and suspicion by distraught parents regarding the vaccine in subsequent years. However, the study was later discovered fraudulent and retracted from the scientific literature.
Another common myth was the idea that poor parental practices contributed to the development of ASD in children. In the 1950s and 1960s, certain proponents of this theory, such as Bruno Bettelheim, alleged that emotionally detached or unresponsive parents led to the typical traits associated with ASD, such as social difficulties and lack of emotional reciprocity in children. However, studies have discovered the opposite effect, in which the autistic child’s symptoms and co-occurring mental health conditions, such as depression and anxiety, rather than the parent’s behavior themselves, are what can cause a strained relationship between caregiver and child due to the stress associated with parenting a special needs child. Additionally, some studies have even shown that as much as 50% of autistic children have a very secure attachment style, or warm relationship, with their parents and caregivers, further debunking this misconception.
What the Literature Says Can Cause Autism
A growing body of scientific literature points to the fact that autism has a primarily biological and genetic component to its etiology. To further support this claim, studies between identical twins have shown that if one sibling is diagnosed with autism, there is a 60% chance that the other sibling will be as well. For fraternal twins, that chance is 20-30%. When accounting for a broader spectrum of autism, there is a 92% chance among identical twins and 10% among fraternal twins.
In addition, pregnant women who were prescribed thalidomide, a medication that treats nausea, 24 days before gestation were shown to be at an increased risk of birthing an autistic child due to the medication causing structural changes in the fetus’s nervous system. Also, some research has shown that possible exposure to rubella, a virus, before birth, can also be associated with a risk of developing autism. Furthermore, a 2021 study conducted by Harvard T.H. Chan School of Public Health has also hinted at the possibility of air pollutants and toxins increasing the risk of an unborn child developing ASD.
So why is it Increasing?
What accounts for the steady increase in autism prevalence over the years? This phenomenon can be attributed to many factors that warrant careful consideration. Examining various elements that may contribute to the rising numbers is essential to comprehend this trend fully. These factors include the following:
Increased Awareness: Autism has received considerably more attention in the media and public domain than in the past. This is especially true considering the vaccine controversy. Increased media coverage and heightened sensitivity have contributed to parents' and physicians' earlier detection, screening, and diagnosis. Evidenced by this is the fact that autism prevalence has increased in parts of the world where it was previously underreported, such as Africa and Asia.
Changes in Diagnostic Criteria: ASD did not appear with its diagnostic criteria until the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), published in 1980. Since then, the DSM has undergone numerous revisions, such as including higher-functioning forms of autism, like Asperger’s syndrome, as part of the overarching definition of ASD. These expanded criteria would enable more children and adults to receive a diagnosis.
Misdiagnosis: The expanding definition of autism criteria can create a double-edged sword. While it helps to detect children who are on the spectrum, it can also misclassify other children who have symptoms that can be misrepresented as autism but are otherwise afflicted by entirely separate conditions, such as intellectual disability and communication disorders. For instance, the International Classification of Diseases, 11 Revision, or ICD-11, does not distinguish intellectually disabled autistic individuals from non-intellectually disabled autistic individuals, which can blur the line between non-autistic intellectually disabled children and autistic children, potentially leading to misdiagnosis. This can lead to an overestimation of the number of people who are autistic.
Environmental Factors: Changing environmental conditions have also contributed to the rise in the autism prevalence rate. Advancements in both prenatal and postnatal care of premature infants have led to increased survivability of susceptible infants who would later develop autism. There is also the effect of thalidomide on an unborn child’s neurological development and exposure to the rubella virus as contributing factors. Other studies have also hinted at the possibility of air pollutants and toxins playing a role, especially with increased population growth and industrialization.
Implications of Autism Prevalence Rates on Public Health
The rising prevalence of autism, as evident in the data, demands urgent attention and intervention. Early diagnosis in childhood enables prompt access to essential support and resources. Additionally, evaluating and testing adults who may have higher-functioning autism but went undiagnosed in childhood (Figure 3) can greatly benefit them. We can significantly enhance their quality of life and overall well-being by providing necessary accommodations and support.
Conclusion
Autism is an emerging public health challenge that requires further research to fully comprehend so that we can better support populations on the spectrum. Before the 20th century, autism was largely unknown. However, changes in population dynamics, increasing knowledge and awareness, and environmental influences have brought it to the forefront of our understanding of neurodevelopmental conditions. Moving forward, there should be a higher emphasis placed on early comprehensive screening to detect ASD and other neurodevelopmental conditions, even in children who are verbal and do not exhibit the typical characteristics associated with ASD.
This would allow for early diagnosis and intervention. Moreover, there should be more community education and awareness across all sectors of society to recognize signs of autism; this would potentially empower families, schools, workplaces, and other settings to create more inclusive environments for those on the spectrum and better understand their sensory and social needs. For some individuals, ASD is neither a disability nor a handicap but a unique identity, similar to how gender identity and sexual orientation are perceived. As definitions evolve and more research emerges, the number of people identified on the autism spectrum continues to grow.
Frequently Asked Questions
Do vaccinations cause autism?
The research says no. Vaccinations like the MMR vaccine do not cause autism. The vaccine protects against the rubella virus, which research shows can be linked to the development of autism while the fetus is in the womb.
What are the current statistics regarding autism?
As of 2024, about 1 in 36 children are diagnosed with autism, according to the Centers for Disease Control and Prevention (CDC). This is higher than the 2018 estimate, in which 1 in 44 children were diagnosed with ASD.
Can autism be cured?
No. Autism is not a curable condition, but it can be managed through effective therapy, accommodations at school and work, and, in some cases, medication.
What factors contribute to the prevalence of autism?
Exposure to environmental agents, such as air pollution, toxins, and chemicals like pesticides, mercury, or even lead, has all been implicated. In addition, genetic factors also play a role, as autism is a heritable condition.
What are the implications of these prevalence rates on public health?
What the data shows is that the increasing autism prevalence should be addressed and tackled. Early childhood diagnosis is critical to provide support as soon as possible. Adults who were never diagnosed as children with higher-functioning autism should also be evaluated and tested to provide necessary accommodations and support.
Sources:
Air pollution linked with increased risk of autism in children. News. (2021, May 27). https://www.hsph.harvard.edu/news/hsph-in-the-news/air-pollution-linked-with-increased-risk-of-autism-in-children/
Centers for Disease Control and Prevention. (2024, May 16). Higher autism prevalence and covid-19 disruptions. Centers for Disease Control and Prevention. https://www.cdc.gov/autism/publications/higher-autism-prevalence-and-covid-19-disruptions.html#:~:text=Data%20collected%20by%20the%20ADDM,communities%20across%20the%20United%20States.
The Children’s Hospital of Philadelphia. (n.d.). Vaccines and autism. Children’s Hospital of Philadelphia. https://www.chop.edu/vaccine-education-center/vaccine-safety/vaccines-and-other-conditions/autism#:~:text=A%20report%20published%20in%201998,MMR%20vaccine%20is%20typically%20administered.
Crowell, J. A., Keluskar, J., & Gorecki, A. (2019, April). Parenting behavior and the development of children with autism spectrum disorder. Comprehensive Psychiatry. https://www.sciencedirect.com/science/article/pii/S0010440X18301925
Hutton, J. (2016, February 1). Does rubella cause autism: A 2015 reappraisal?. Frontiers in human neuroscience. https://pmc.ncbi.nlm.nih.gov/articles/PMC4734211/
Matson, J. L., & Kozlowski, A. M. (2010, July 8). The increasing prevalence of autism spectrum disorders. Research in Autism Spectrum Disorders. https://www.sciencedirect.com/science/article/pii/S1750946710000917
MD, C. L. (2019, July 19). 3 charts: Genetic heritability of autism: Visualized science. clearvuehealth.com. https://www.clearvuehealth.com/b/autism-genetics-heritable/
Richter, F. (2024, April 2). Infographic: The rising prevalence of autism. Statista Daily Data. https://www.statista.com/chart/29630/identified-prevalence-of-autism-spectrum-disorder-in-the-us/
Zapata, K., & Sheehan, J. (2023, August 20). What causes autism in children? 6 facts you need to know. Parents. https://www.parents.com/health/autism/facts/6-facts-you-need-to-know-about-autism/
Zeidan, J., Fombonne, E., Scorah, J., Ibrahim, A., Durkin, M. S., Saxena, S., Yusuf, A., Shih, A., & Elsabbagh M. (2022, March 3). Global prevalence of autism: A systematic review update. Autism research : official journal of the International Society for Autism Research. https://pubmed.ncbi.nlm.nih.gov/35238171/
Figure 1: CDC. (2024, May 15). Higher Autism Prevalence and COVID-19 Disruptions. Autism Spectrum Disorder (ASD). https://www.cdc.gov/autism/publications/higher-autism-prevalence-and-covid-19-disruptions.html
Figure 2: 3 Charts | Genetic Heritability of Autism | Visualized Science. (n.d.). Www.clearvuehealth.com. https://www.clearvuehealth.com/b/autism-genetics-heritable/
Figure 3: Richter, F. (2023, March 31). Infographic: The Rising Prevalence of Autism. Statista Infographics. https://www.statista.com/chart/29630/identified-prevalence-of-autism-spectrum-disorder-in-the-us/
About David Martin, BA
I graduated from the University of Maryland, Baltimore County, with a Bachelor of Arts in Biological Sciences and a Minor in Sociology. I am pursuing my master's in public health with a concentration in epidemiology from Benedictine University. As an aspiring epidemiologist, health researcher, and advocate, I seek to utilize my skills in conducting analytical research to influence health policy decision-making and preventative healthcare to achieve equitable health outcomes for everyone.
