Schizoprhenia has nothing to do with basic character. The notion that I was raised in wih the JWs that mentally ill people were Satantic is hogwash. Schizoprehnia is a brain disorder. A complex brain disorder. I've know college professors, performing musicians, art dealers, very nice peope with schihzprehnia. It may have been a highly functional segment but they were schizoprehnic.
I can't vouch for the origin of voices for Jesus and Paul. Hearing voices, paired with grandiosity, is pathological. I forgot the technical term but lack of insight into your disease is a main symptom of schizoprehnia. If someone were raised in a Native American culture, the voices might not be pathological.
Would any god speak in such paltry languge?