Which was discovered first, autism or Tylenol? What to know

In September 2025, U.S. President Donald Trump suggested in a press conference that the use of Tylenol during pregnancy was linked to an increased risk of autism in children. In the U.S., Tylenol is the leading brand of acetaminophen, a drug commonly used as a pain reliever and to reduce fever. Trump urged pregnant women to avoid taking the drug, despite there being no definitive evidence for Tylenol or acetaminophen more broadly causing autism in children.

In the days following Trump’s press conference, people on social media began countering the suggestion that Tylenol may cause autism by claiming that autism was older than Tylenol. The claim appeared in popular posts on Facebook, X (archived) and Reddit (archived).

The claim that autism as a diagnosed condition was older than Tylenol, the brand of acetaminophen Trump said pregnant women should avoid, was true. And although acetaminophen’s history dates back further than Tylenol’s, evidence exists that autism has been around for much longer, even if it wasn’t formally diagnosed until the 20th century.

Tylenol

Tylenol debuted in 1955 with Tylenol Elixir for Children, according to a history of Tylenol produced by the communications firm Nancy West Communications, which included Tylenol’s creators, McNeil Consumer Healthcare (formerly McNeil Laboratories), on its clients page. In 1959, the same year the pharmaceutical company Johnson & Johnson acquired McNeil, Tylenol became an over-the-counter drug.

The history of acetaminophen in general began in 1878, when the chemist H.N. Morse first prepared it, according to the American Chemical Society. According to an article on the Tufts University School of Medicine website, acetaminophen’s first recorded use for treating pain and fever took place in 1893. 

However, these dates for the origins of acetaminophen and its use aren’t as cut-and-dried as Tylenol’s debut date. That’s because while acetaminophen was invented in the 19th century, there wasn’t widespread use of the drug or even much availability of it until several decades later.

A Tufts University news article said acetaminophen didn’t come into widespread use until the creation of Tylenol. A now defunct Yale School of Medicine article from 2009 went a step further, claiming the drug was never developed, manufactured or marketed before Tylenol. The FDA didn’t approve acetaminophen for the first time until 1951, the drug’s PubChem page says.

Autism

Autism — or autism spectrum disorder (ASD), as it’s called medically — is a difference in how someone’s brain works that causes unique ways of socializing and behaving, according to a Cleveland Clinic informational web page about the condition. According to that page, there are no uniform signs or symptoms of autism visible in every autistic person; each autistic person is different and may experience any number of different effects at varying levels of intensity. Some behaviors or traits common in people with autism are difficulties with conversation or speaking, difficulties understanding social cues, little to no eye contact in social situations, intense or highly focused interests, strong preferences for routine and repetitive use of certain words, sounds or movement to regulate emotions.

There are two main origin points for autism’s classification as a distinct condition. First, in 1911, Swiss psychiatrist Eugen Bleuler introduced the word “autism” to describe a group of symptoms in some patients with what was then considered schizophrenia, according to Golden Steps ABA, a therapy group for autistic people. Bleuler described the symptom or symptoms he called autism as “a ‘turning inward into the own world’ and a denial of contact,” according to a 2018 article in the journal BJPsych Advances.

In 1943, psychiatrist Leo Kanner published his findings from a study of 11 children he diagnosed with “Kanner Syndrome,” which became the basis of ASD, according to the U.K.-based The Autism Service, a clinic dedicated to patients with autism and ADHD. While Kanner’s 1943 findings are often credited as the discovery of autism as a unique condition, his work “shared striking similarities” with the 1925 findings of Russian child psychiatrist Grunya Sukhareva, whose research was overlooked in the Western medical community.

Smithsonian Magazine wrote that later in his career, Kanner said, “I never discovered autism. It was there before.”

In other words, it’s correct to say that autism as a subject of scientific study is older than Tylenol as a brand.

What about acetaminophen?

Some have argued (archived) that the claim is false because acetaminophen was invented in the late 19th century. However, there’s still evidence that autism is older than even the generic form of Tylenol.

Even though the medical community didn’t recognize autism as a distinct, diagnosable condition until the 20th century, some conditions described in prior centuries align with what we know as autism today, and evidence exists of people who likely had autism before medical experts identified and labeled the condition.

For example, in 1801 the French physician Jean-Etienne Dominique Esquirol described a condition that included symptoms such as a lack of speech and social withdrawal. He called the condition “idiocy,” according to Golden Steps ABA. “Incapable of attention, idiots cannot control their senses. They hear, but do not understand; they see, but do not regard. Having no ideas, and thinking not, they have nothing to desire; therefore have no need of signs, nor of speech,” Esquirol said when defining the term, according to the Minnesota Governor’s Council on Developmental Disabilities.

In 1848, medical doctor Samuel Howe presented his “Report Made to the Legislature of Massachusetts upon Idiocy,” for which he studied and recorded data on people then referred to as “idiots” in Massachusetts. A 2016 article in Smithsonian Magazine said many individuals Howe described in his report behaved in ways consistent with what is now known as autism. Smithsonian Magazine highlighted one individual from the report, Billy, whose “ability to use spoken language was severely limited” but who had “perfect musical pitch and knew more than 200 tunes.”

Some researchers believe that in earlier times people used folklore to explain those with disabilities, and that tales of changelings may have been used to describe children with developmental disabilities including autism, wrote Kayley Whalen, a Ph.D. student studying sociocultural anthropology, for the Autistic Women & Nonbinary Network in 2023. In Irish folklore, changelings were the lookalikes fairies left behind after abducting children. Whalen wrote that changelings in stories often exhibited intelligence and behavior that didn’t didn’t match the child’s apparent age. “They may be prodigies who can talk, sing, and dance with incredible skill far beyond a typical child. Or, conversely, they may seem to develop much slower than other children,” she wrote.

It’s impossible to know with certainty if any of the people in those cases, whether the ones Howe studied or the children who inspired changeling folklore, were autistic according to modern diagnostic criteria. However, it is evidence that the behaviors often associated with autism existed long before scientists first described autism as its own condition.

The existence of something prior to another thing, in this case autism and Tylenol, does not definitively disprove that one causes the other. However, there is no definitive evidence that Tylenol taken during pregnancy causes autism in children, and there is evidence that untreated pain and fever during pregnancy can carry serious risks for both the parent and fetus. Snopes wrote about the current state of research on Tylenol use during pregnancy and autism here.