Smallwonderer, sure, but I don't know how to start such a poll (can't edit my original/first post anymore).

ValentinaVVV, those with schizophrenia (probably also but less so SZA (there is relatively little research done into SZA), BP lesser still) are more markedly any psychotic disorder trait or more abnormal given some biological markers, because of the severity of their problems, early prodrome relative severity, causing relatively early onset in most cases.

BP is more heterogeneous and it is not easy doing research with such a group. There is (more and more) a move towards at least separating (controlling for) BP-I from BP-2, but even then it seems like there must be subgroups that are in some way more like those with SZ and others that

I think prodrome severity is the best way to go about this. So not just feeling (somewhat) different as a child or having mild mood swings or sleep disturbances, but rather serious problems already (with memory, conceptual organisation and beliefs, pervasive fantasies, as well as sleep, mood and expression). It is more common in SZ, but it can certainly be part of some BP (both BP-I and BP-II) or even relatively mild-BP BPD.

I guess the specifier "with psychotic features" would be necessary, but not sufficient.