My pdoc believes that some parts can be depressed and others not, same with anxiety. And he thinks that DID patients often need a variety of meds because different parts may react differently to different meds.

I am not sure about the meds, to me it seems more like they just don't work. But I do agree that there are depressed parts/suicidal parts/anxious parts. Every part is not depressed or anxious. I also have the diagnosis of mixed personality disorder-I feel pretty clear that there are parts with dependent personality disorder, parts with avoidant and perhaps parts with schizoid (although the schizoid may be more a result of the other two playing out in ways that seem weird).

So for me, yes, different parts seem to have different mental health issues.