Other voices would have other messages: maybe that the patient was a horrible person who deserved to die, or that the patient must complete some bizarre ritual or else doom everybody. There were relatively fewer voices saying "Hey, let's go fishing!"

There may be a bit of a selection bias here. If the voices are saying "let's go fishing" or "those shoes are so last season, you really ought to get a new pair" or even "better run disk defragmenter again just to be sure" the person probably does not wind up hospitalized.

There was an article a year or so back in the Times about people with mundane voices in their head forming a support network at it mentioned that this may be much more common than is often thought.