Voices aren't always the end-all; schizophrenics have extraordinarily active imaginations, and sometimes entire worlds go through their heads. I have little formal training in this kind of thing, but what I do know is that our world is extremely stressful for them; there's just too much input, and lots of schizophrenics attempt to filter and categorize all of it.

Most require medication, although certain individuals can be placed in low stress environments (rural farms without machinery were the location in the case study I read) and be fine. Later stages of schizophrenia ofern include something referred to as "posing", where they will stay in a single pose for long periods of time, their attention consumed completely by events in their own heads.

Not a lot is known about schizophrenia, and there are lots of theories about where it comes from and what causes it (including a recent idea that it can be contracted as a viral zoonosis from domestic cats).