I'm afraid this is one issue on which I must respectfully disagree with you guys.  I think that there are all sorts of ways that words describing various mental conditions -- or physical ones for that matter -- can and are properly used figuratively, not literally.  There's always the chance that someone might misconstrue the usage as literal but usually context clarifies the issue.

I mean, just off the top of my head I can think of all sorts of good, colourful and descriptive adjectives that help us communicate but which fall in this category.  We say someone's paranoid when we think they're being unreasonably afraid they're being targetted somehow.  It doesn't mean we actually think they're clinically paranoid although I guess, in extreme cases, that's always possible.  Or we say someone's acting crazy.  Well, crazy might not be the most specific or sophisticated diagnosis but the fact is there are people who are clinically crazy.  

Or maybe better examples of words that serve as both clinical descriptors and general ones might be "narcissistic" or "grandiose". 

Anyway, you get my point.  To gut the language of any of these words for general usage just because they've got a specific, usually more severe, connotation is just limiting speech too much, in my opinion.  In this case, I think "schizophrenic" does a great job capturing the weird, unhealthy split thinking of premies and anyone who believes they've got not one but two conscious centres within, the mind and the heart.