Will Graham is autistic.
It’s the little details that make his character: his tendency to pick up speech cadences from whomever he’s around, his body language, his difficulty with understanding what he’s thinking or feeling, the fact that everyone around him infantilizes him, even his fashion sense being ‘this appears to be sort of generally clothes-shaped’. He’s one of the best-done autistic characters on television…
Except that Bryan Fuller’s opinion on Will Graham’s autism is “For Will Graham, there’s a line in the pilot about him being on the spectrum of autism or Asperger’s, and he’s neither of those things. He actually has an empathy disorder where he feels way too much and that’s relatable in some way. There’s something about people who connect more to animals than they do to other people because it’s too intense for whatever reason.”
(Yes, Bryan Fuller did give a description of some people’s experience of autism as a reason why Will Graham could not possibly be autistic.)
Most people would consider my thoughts on Will Graham’s autism to be a headcanon, in the same sense that thinking he’s LGBT or a person of color would be a headcanon. But I don’t think it’s irrelevant that if Will Graham walked into the office of any competent, non-cannibalistic psychiatrist in the country, he’d walk out with an autism diagnosis. That is far more grounded in the text than most headcanons. Indeed, it’s the clear and obvious interpretation.
The solution to the mystery, I think, is precisely that authors don’t know what autism is. 1 in 68 people are autistic; therefore, nearly all authors have met at least one autistic person, and most have met several. However, they’re not likely to know that the people are autistic. Many autistic people do not disclose their autism; some might not ever have been diagnosed. And because they don’t really know what autism is, they’re not going to recognize the signs.
Compare this to homosexuality. Many gay people are out in every part of their lives; the gay people that any author has met are very likely to identify themselves as gay. And homosexuality is legible in a way autism isn’t. Visibly autistic people are not usually read as autistic; they’re read as weird or nerdy or high or a vague undifferentiated “special needs”. On the other hand, a man who kisses another man is easily recognized as gay.
For this reason, authors have autistic traits as part of their general sense of what people do, without understanding that those traits are autistic. (I’m not saying that authors model their characters on any specific autistic person, although that’s some writers’ process– I’m saying that when an author’s subconscious mind thinks “hm, what would it be plausible for this person to do?”, autistic traits are included as part of the things it is plausible for people to do.) When they want to write a character who is weird or nerdy or vaguely special needs, they wind up writing a tremendously accurate autistic character– by accident.
Indeed, these characters are usually much better depictions of autism than the characters that are supposed to be autistic, because the latter are influenced by the author’s stereotypes and pathologizing depictions of autistic people, while the former are based on actual autistic people.
This doesn’t apply nearly as much to gay headcanons, because it is extremely rare for authors to know that typical gay behaviors exist without connecting them to the existence of gayness. (It is, interestingly, possible that an author knows of the traits of self-closeted trans people without knowing that those are self-closeted trans person traits– but I’m not sure if there are commonly unintentional self-closeted trans people in fiction outside of transformation fetish porn.)
In conclusion: there is a sense in which Will Graham is ‘canonically’ autistic which would not apply to more normal headcanons like him being gay or polyamorous or trans, and the same thing apples to a bunch of other neurodivergences.