I've noticed that his speech patterns are, for lack of a better word, "off."
You can notice this easily on Twitter, where his posts quickly devolve into what seem like badly-translated haikus.
People like to throw around the appellation, "autist" but I think Antony really fits the bill.
It seems like Antony is suffering from echolalia in particular, as he spouts off popular phrases that have little connection to the current topic.
https://www.youtube.com/embed/6__ex0_5gp0
In the video above, he keeps mentioning Armored Skeptic and Shoe On Head, though this could be based on a paranoid delusion just as much as echolalia.
https://www.youtube.com/embed/yxP9qRrIp_g
He has a Shatner-esque manner of emphasizing certain words while getting other words out in a rush. He really does a hatchet job with "have a nice day" at the end (sing-song voice - look at the traits for autism in speech).
When was the last time you heard about "moral fee-fees"?
EDIT - Given how much he speaks about Gamer Gate and the role he assumes the loosely-affiliated group has to play in "exposing" what he is, his mentions of Armored Skeptic and Shoe On Head lean more toward a conspiracy theory.
I'm no expert in communication disorders or social disorders, but I think there's an actual case for autism here.
inb4 armchair psychologist