I wish I could help you more but the only advice I can offer is that I agree with you that it doesn't sound like BP1.

I was diagnosed with BP1 and had to be admitted involuntarily. Based on my own experience and the experiences of other people described to me who I met in the ward it's not common for BP patients to hear outside voices. Outside voices seemed like a schizophrenic symptom. For me, when I'm manic or hypomanic the "power" always comes from within.

The only way I can describe it is that I don't get "told" things from BP, I feel them. So while a schizophrenic might think a friend, family, God, or a higher power is telling them something, with BP that comes from within as an indescribable feeling. I might wake up in the middle of the night and feel like I have to look through the window and I'm going to find something there. I don't know what's going to be there, it's usually always nothing, and after I do it I'm left kinda confused and frustrated because I know I had a reason to look out the window, but I have no logical explanation or ability to describe why. It's just a fleeting moment I have to act on that instant and the feeling disappears when I carry out the action and I get no satisfaction.

I got a bit lucky because this all happened during the height of covid which resulted in me thinking I had covid because I was so confused with what was happening to me (waking up in middle of the night, needing to go places, feeling like I had to be at specific place at a specific time for some event but nothing was there, wanting to switch careers from software eng to lawyer etc.) that I went to the emergency room a couple times in the same day to get tested for covid and they recommended I come see them the next morning and talk to someone about what's happening to me.

I did that, had a manic moment waiting for the doctor the next morning in the waiting room and then and was stuck in the psych ward involuntary.

Lucky for me being hypomanic or manic is so irrational to me and the thoughts I have get so irrational that I know how to catch it early and avoid full blown episodes. That's the only way you may be able to convince your wife - if she understands her thoughts and feelings are irrational hopefully you can convince her to seek help.

The other thing is the cyclical nature of the diseases. I can tell my psychiatrist ahead of time in May to up my meds because June - September are my roughest months for my mania and I can feel it start to come on late May. Bipolar you'll cycle through depression in the winter and mania in the spring/summer generally. Schizophrenia from my understanding has 3 stages. If your wife goes from depression to mania on a dime based on the seasons that sounds more like BP. If she doesn't have the mood swings and hears voices it's probably schizophrenia.

I'm surprised your wife would accept and live with her BP1 diagnosis but not consider the possibility that she may be schizophrenic. I would start with the irrationality of the strangers talking about her. Why does she think strangers would talk about her? Leave the possibility open that maybe the family is, don't dispute that too much, and focus on the strangers and doctors. You can't even get doctors to talk to you about her, why would they talk about her behind her back to other people? Also be sure not take the questions too far. If she's getting upset, confused, or angry with the questions you should stop because you could be aggravating the situation. Don't accuse her of not making sense or sounding crazy, just ask why she thinks what's she thinking.

Good luck with whatever it is, sounds like she has a terrible disease either way :(