I was diagnosed ADHD in my 50’s which, in a way, was a relief as the “beast” finally had a name.
As for any connection between ADHD and ABDL and/or continence issues, there is research indicating a link between ADHD (and, I’d assume ASD?) and a delay in emotional development, but it’s complicated by other factors such as parenting and, particularly in my case, the trauma of potty training.
My mother wanted me out of diapers ASAP, much faster than I remember being ready to handle. To this end she would shame me, then punish me with spankings, whenever I had an accident. One occasion still seared in my memory is of being outside playing when, suddenly, I felt the need to potty and, just as suddenly, I did. By the time I made it to the house the deed was done, and I got spanked.
There are so many variables that can affect how any child, especially with ADHD/ASD, develops and matures, I’m not sure how you tease out something as anecdotal as my experiences, and apply it broadly to the diagnosis.
My two cents…