Hi fern, thanks for the welcome! I appreciate the input, and schizoaffective is definitely something I've considered. However, with schizoaffective I would expect the psychotic symptoms to always occur, whereas for me they're definitely tied to mood swings.

I'm more and more starting to think along the lines of a spectrum like you mentioned, at least for the schizoid part of the diagnosis. I'm even starting to think I should just focus the treatment on the bipolar (which is a lot more tangible for me) and just accept the schizoid traits for what they are. For what it's worth, my psychiatrist has also done some tests for autism (which can sometimes appear similar to schizoid PD in some respects), but those came back negative.