Diagnosed with both (as a child, then again as an adult after ignoring said diagnosis for a long time) I’ve been continually told there is a close link between the two, in that it’s not uncommon if you have one, to be diagnosed with the other.

I’ll say I’ve found “treatments” from both schools helpful. Even though I resisted stuff on the autism side for a long time because I felt “insulted” by it and was convinced it was a diagnosis made in error.