There's all types of schizophrenia...I hear people knocking at my door, the phone ringing, loud crashes, conversations, whispering in my ear,, doorbells,, etc and the diagnosis was schizoaffective disorder, which is not as severe as full blown schizophrenia. Those with bipolar or manic history most likely to experience this.
I too have a problem discerning reality from 'my reality'......when these episodes happen I now know not to answer the phone or answer the door -- I wait and look at caller ID. It is maddening for sure.