I know this is a bit of an old thread to necromance considering it’s from 2017, but I’m an ADHD adult and i’ve had special interests my whole life without being diagnosed on the autistic spectrum.
And @eliz2112’s question never seemed to get an answer, and was somewhat derailed. So to answer Eliz, 2 years late:
I’m 27 now, but ever since I was a little kid, I had an intense interest in mythology and folklore, and pirates to the point I had stacks upon stacks of books about the golden age of piracy, dragons, magic, fairies, sea creatures. I’d spend alllll my pocket money in a corner store that sold these beautiful fairy statues to the point the shop staff had nicknamed me the ‘fairy girl’. I made my parents take me to castles and museums because I loved seeing the ancient buildings. I spent hours and days researching folklore and greek gods. I still have friends buy me dragon themed stuff even now.
The moment anyone brought these things up, i’d infodump for as long as I could talk for before I’d get told off for ‘talking too much’, or ‘being too loud’, because I was so excited to share my special interest with people, and everything I knew and learnt.
These were HUGE sources of great joy, and literally encompass my thought space because I always want to learn more, and talk more about it, and it fed into my career too as a story artist when I got older.
(When I was like an even tinier child, my whole world was the Aristocats and Spice Girls. I also have a special interest in tennis I got when I was a teenager!)
So to differenciate from @caringmom’s issue:
The thing with OCD obsessions is that they cause severe anxiety and distress, or they’re used as a comfort cruch to mitigate the anxiety. If I have/do X then Bad Feeling stops.
The difference in a special interest for Autism (or ADHD), is that it brings us great joy, and only distresses us when have to get pulled away from the thing we so wholly enjoy, because we’re enjoying it and want to be engrossed in it, and it’s our whole world.
(of course, as with anything, things can overlap).
As for Hyperfocus, like the article says, that’s a state of ‘focus‘ not an intense interest. Hyperfocus is part of executive dysfunction, as it’s the ‘inability to switch tasks’ (inertia) facet, and so we get stuck doing the task for several hours (whether that’s a game, or tidying bedroom, or searching for something).
It’s not a special interest, but it’s really easy to hyperfocus ON your special interest when you start researching it and suddenly five hours have ‘magically’ passed and you really need to use the bathroom. 😭