I'd assume due to the difference of neurodivergent individuals either not wanting to do certain things or acting certain ways may have been misconstrued and then later recognized as part of the spectrum. Don't know any work on the subject as I assume it's too niche, but it's just my two cents as to why

I got diagnosed with autisum,odd, and explosive disorder all at one time at the age of 15. But when I found my people later on we discussed it and all have at least 2 of the 3 disorders in common. So I feel like it is fairly common. I wonder if the odd and possibly the explosive disorder come from how out caregivers treated us. Like for me I feel like my parents being so hard and thinking I was just a discipline problem or a spoiled brat and forcing me to act or do certain things like eye contact and always talking over me when I was having issues talking was a big part of it. Even to this day i feel like if I could get the words out of my mouth they would still talk over me and dismiss the issues I have because I'm "spoiled" and just continue to gaslight or halfway apologize or just dismiss it completely

I had the odd and the explosive disorder but never the autism spectrum disorder. Now it’s just odd and bipolar 2 idk if that’s common or not tjo

I'm not diagnosed with autism, but I have my suspicions. My brother has it, and we have a lot of the same struggles, his is just a lot worse, so I'm not sure

I have odd and also have adhd

I got dianosgised at 16 in the pysch ward when I wasn't particularly listening to all their stupid rules. It is just autism tbh