Others have answered but I feel obliged to add this.

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Others have answered but I feel obliged to add this.

Until the early 1900s, "mild" mental illness such as autism just didn't exist in a medical sense. People were "odd", "eccentric" etc and even after autism was formally recognised and studied in the 1940s it was virtually unheard of. Again, people were odd, a bit weird or eccentric.
There are no records of diagnosed cases of autism or similar before the 1900s because nobody recognised them for what they were.
Serious mental health issues have been recognised for thousands of years. Records of diagnoses of "lunacy" and "insanity" go back to the 1400s in the UK. Back then the cure was imprisonment in a cage and with regular blood letting and being plunged in cold water.
Back then the cure was imprisonment in a cage and with regular blood letting and being plunged in cold water.
And by drilling holes in the skull. Plus probably various other horrible 'treatments' that just created extra problems without fixing the original (and very vaguely understood) issue.
Autism as a diagnosis is relatively new, but people would have always had traits that would be thought of as nowadays as autistic. As an example, Rube Waddell was a professional baseballer in 1897 who was so fascinated by firetrucks that he would run off the field mid-game to chase them.
Is gravity something new or did it exist before Newton described it?
Here's a metaphor. With technological advancement we're discovering new stars every day. Does that mean they just appeared?
The old joke “what was the tallest mountain before Mt. Everest was discovered?”
“Mt. Everest”
Olympus Mons
Mouna Kea, it's got a larger base to tip hight, it's just mostly under water.
Well, if no one could observe them, you could say that they both existed and not existed.
The word is fairly new. But so is a shitton of other medical diagnosis like "cardiomyopathy", "congenital heart disease", " carditis", "aortic aneurysm", "peripheral artery disease", and on and on
I choose to believe that autism appeared only after the invention of railway, and you can't convince me otherwise.
I can't find it right now but if I could I'd post the one about the ancient greek or roman dude with a interest in ships that would watch them enter and leave port and knew each one by name
I think it was more specifically the creation of Thomas the Train engine.
Even as recently as 30 or 40 years ago, "problem" children would be hidden away, either in the home or sent to some sort of facility. Neuro divergence was a hidden issue.
I was "easily distracted" and "underperformed" and "could do better" at school. Always the "weird" kid. Only diagnosed when I was an adult because "autism" just wasn't really a thing*. This was 40+ years ago. The general treatment approach was getting The Belt haha or sent to my room, or sent to my gran's, or sent "out to play".
*edit: when I was a kid
That sounds exactly like my story though, by the looks of it, I am a bit younger than you.
I know you’re not supposed to diagnose historical figures, but Kant is like the textbook definition of autistic. He made the rule that he would smoke one pipeful of tobacco a day, and lamented for years that he couldn’t find a bigger pipe. His moral philosophy also demonstrates the kind of rigid thinking that is characteristic of autism.
I never correlated this but it sticks. Another notable probably autistic figure was Isaac Newton
We used to mark all sorts of neurodivergent people as "crazy" or "witches". But I'd also be interested in a historical source if someone has one.
Just because it's diagnosed easier now doesn't mean it didn't exist.
"Certainly there are people, nay, very many, who will smile at [my predicament], because they are not sensitive to noise; it is precisely these people, however, who are not sensitive to argument, thought, poetry or art, in short, to any kind of intellectual impression: a fact to be assigned to the coarse quality and strong texture of their brain tissues." -Schopie complaining about overstimulation
It has been around as long as humans have.
(Autists perspective)
It's not new at all, the term has been around decades and itself has been around literally forever. It's a different brain development. There are many historical persons which are thought or know to have been autists (e. G. Einstein, Lewis Carroll, Dan Akroyd to just name a few over a longer timespan.)
It's also not having autism (as an optional trait) but rather being Autist (as a defining foundation).
Just like, say, mutations that also always happened to certain degrees.
Feel free to ask. Also, of course, that is my personal opinion where it is not scientifically proven.
I get the vibe that Gregor Mendal probably was autistic. Likewise, Da Vinci probably was ADHD.
we're a kind of people that's been around probably since forever. categorizing us the way modern psychology does is of course a more recent phenomenon. every culture since the dawn of time has had their own ways of handling and understanding variation in the species, but the variations have probably existed for as long as humans have, if not longer.
Some quick extra bullet points as I'm short on time and much of what I want to say has already been said in this thread:
You know how there's the old schoolhouse stereotype that there's always a "weird kid" in every class? There's a good chance that kid was an undiagnosed autist.
The current estimates for autism rates is around 1 in 30. Which means every classroom is expected to have 1 autistic kid. Matches perfectly with the "weird kid in class" stereotype. People recognized autism since forever. That's why the stereotype exists. It's just that they didn't have an actual word for it yet.
Is being left handed something old?
No, being left handed only means you're a satanic spawn or something evil
At least fifty years, and according to my mum at least 75 years.