Yes, here, I can say that I have PTSD. To myself, I can say that I have PTSD, but to the real world - no. Admitting it to myself makes me feel less abnormal. Getting the diagnosis made sense, but it hasn't really started the healing process.
It's an interesting question. In my experience, any 'mental health issue' still has a stigma attached. And I work in health care. Here (on this forum), it is accepted, but in my world it is not.
I'd like to say that "I have PTSD, but it does not have me", yet it invades every inch of my being. I cannot escape it, and so far, cannot heal from it. The fact that it is only manageable and not curable is particularly daunting, because I cannot live like this forever.