According to a recent surveillance summary by the CDC, the prevalence of autism has risen significantly amongst children aged eight years old. This statistic has sparked concern, curiosity and unfortunately, a resurgence of outdated and inaccurate theories about the causes of autism.
Yet, despite what headlines, internet echo chambers and Robert F. Kennedy Jr. may tell you, this rise does not point to an inexplicable spike in the number of people being born with autism. Nor does it point to an increase in children “becoming autistic.” The reality of this statistic is far more promising: mental health professionals are simply getting better at identifying autism early on.
Thanks to continual rigorous psychological research, we know much more about autism today than we did just a few years ago. Here’s what we know about its prevalence and causes — and what we can definitively rule out.
What We Know About Autism, Its Prevalence And Its Causes
As defined in the American Psychiatric Association’s DSM-5, autism spectrum disorder (ASD) is a neurodevelopmental disorder, characterized most commonly by deficits in social communication. Individuals with ASD may also exhibit restricted and repetitive patterns in their interests, behaviors and preferred activities.
However, for decades, both researchers and laypeople alike had incredibly restrictive views on what these symptoms actually looked like.
Around 50 years ago, professional diagnoses were generally reserved for children who exhibited the most severe and visible manifestations of the condition. These children were often non-verbal, profoundly delayed in learning or developmental milestones and, in some cases, engaged in self-injurious behaviors. Because of these narrowly defined criteria, mental health professionals at the time believed autism affected fewer than 1% of children — roughly one in 2,500.
Today, however, autism is estimated to affect about 3% of children — one in every 36.
At face value, this rise in prevalence might seem intuitively alarming; some individuals have even begun to suggest that autism is becoming something of an “epidemic.” But claims like these are largely fallacious.
In reality, what we’re really seeing is a well-overdue shift in how professionals understand and identify autism. Mental health experts now recognize that autism rarely presents in a single prototypical way. Individuals’ symptoms can vary widely in terms of behaviors, strengths, challenges, communication styles, sensory sensitivities and the degree to which these traits impact their day-to-day life and functioning.
This is why, today, autism is understood as a spectrum disorder — because no two individuals experience it in the exact same way. And, as the CDC explains in their surveillance summary, “Differences in prevalence over time and across sites can reflect differing practices in ASD evaluation and identification and availability and requirements that affect accessibility of services.”
In other words, this increase in incidence reflects our growing ability as a society to recognize and diagnose neurodivergence more accurately and inclusively. That is, it should not be taken as a sign that there’s something causing more children to “get” autism.
In fact, we already know what causes autism: genetics.
This understanding is supported by decades of research, led by a pioneering twin study published in Psychological Medicine in 1995. In said study, researchers found that if one identical twin had autism, there was a 60% to 90% chance that the other twin would show signs of ASD, too. Among fraternal twins, that concordance dropped significantly — to between 0% and 30%.
Since then, even more recent studies have identified a range of genes associated with the development of autism, which have further reinforced the role of heritability in its onset.
Conspiracies And Misinformation Regarding Autism
Almost all of the public distrust surrounding autism’s cause can be traced back to a single, now-infamous study published in The Lancet in 1998. In this paper, British physician Andrew Wakefield falsely claimed there was a link between the MMR (measles, mumps and rubella) vaccine and the onset of autism. Not only was this study completely unfounded, but it was also downright fraudulent, according to the Journal of Medical Regulation.
The study was based on a miniscule sample of just 12 children, and Wakefield deliberately selected data to fit his predetermined narrative. He also conducted invasive (and wildly unnecessary) medical procedures on children without proper ethical approval.
As if it couldn’t get any worse, he also failed to disclose not one, but two major conflicts of interests. These included a financial tie (more than £400,000) to a group pursuing litigation against vaccine manufacturers, as well as his self-made “diagnostic kit” for a non-existent “form” of autism. The latter conflict, in particular, offered him an even heftier opportunity for profit — as hefty as $43 million.
After years of scrutiny, the paper was formally retracted by The Lancet in 2010, and Wakefield was stripped of his medical license. The General Medical Council described his conduct as dishonest and irresponsible. Today, Wakefield is a staunch anti-vaccination activist, and has since been described as “one of the most serious frauds in medical history.”
Yet, despite its retraction and the utter lack of credible evidence behind it, many people continue to believe that vaccines can cause autism. In the years since, more baseless claims have followed: that autism is caused by poor parenting, artificial food additives, toxins or environmental exposures. But none of these theories hold up under scientific scrutiny.
To say claims like these are flagrantly erroneous would be an understatement. Asserting that such factors cause autism is as absurd as saying ice cream causes shark attacks. It sounds ridiculous, and it is — because there’s a major logical fallacy underpinning this argument: the conflation of correlation with causation.
Ice cream sales tend to rise during the summer months, as do shark attacks. But we know it would be egregious to think that it’s the ice cream drawing sharks to the shore. There’s an obvious missing variable at play: the weather. Warmer weather leads more people to buy ice cream and swim in the ocean. The relationship between ice cream and shark attacks is purely coincidental.
Yet, the same flawed logic is thoughtlessly accepted in the argument that vaccines cause autism. Vaccines are, for good reason, routinely administered in early childhood — right around the same time that signs of autism most often become noticeable. But timing does not equal causation.
To insist that one causes the other is to ignore decades of research, as well as to overlook the simplest and most scientifically supported explanation: that autism is a neurodevelopmental condition with strong genetic underpinnings. It is not caused by vaccines, parenting styles or anything else external. People on the autism spectrum have always existed — long before we had a name for the condition or diagnostic criteria to identify it — and they always will.
The incidence of autism hasn’t changed at all. Our ability to recognize and understand it has, and this is not something you need to fear. If anything, it’s something to be incredibly thankful for.
The perceived increase in the development of autism is but one of many psychological misconceptions. How many others have you been misled to believe? Take this science-backed test to find out: Psychological Misconception Questionnaire
