I don't know much, but I do know that after decades of treatment from different mh professionals, they want to evaluate for a diagnosis on their own, and that includes even things that you would think are no brainers, like depression. The ones I've seen only considered a previous diagnosis if it came with a medication and the medication worked for that specific condition. Ultimately, that's what they are after--what medication or therapy approach to take. It's even more difficult with something like d id which doesn't respond to medication, and is so hidden. And there are other factors that have to be considered, like substance abuse, which can skew things. My sister, for example, could say she loses time and behaves at odds with herself, but she's a black out drunk. Did the d id cause the drinking or is the drinking looking like a dissociative disorder? Btw, she does not have d id that I know of. With her, it's either drinking related or she has some kind of psychotic episodes. The main thing is, the drinking makes it hard to diagnose. So if that's on a person's medical record, it's just going to complicate things. I'm not saying it's fair or right, but it is something that will cause a mh professional to want to evaluate for themselves.