You should check out the thread "
Religion and mental-illness", if you haven't already, to read more posts people have made about how their own religion regards mental-illness.
Shaviv
My real question is, where do religious attitudes toward mental illnesses come from? Do they originate from purely secular social forces, or is there a specifically religious nature to them?
I feel that it's probably a little of both, for many religions. First, secular social forces in the general culture decide whether the symptoms of a particular mental-illness are a "good thing" or a "bad thing." At that point, the philosophy of the religion in quesiton might step in if they have a specific belief about where "good" or "bad" things come from.
Shaviv
And what is the significance of those answers, with respect to the treatment of individuals who are suffering from their brains having gone a little off-key?
At this point there may be religious mandates based on the theories above, or there may simply be the normal social force of fear acting upon those dealing with the mentally-ill.