Yes I think it does although not necessarily in a religious context. Having a positive mental attitude does help in the fight against cancer for example apparently. Certainly wouldn't do any harm I think unless you looking to purely the power of prayer to cure you.
China, I agree. A positive attitude helps almost any illness. I know someone who simply refuses to catch a cold - and she never does. Whether that attitude can be considered 'spiritual' is debatable, since she isn't a 'spiritual' person in any shape or form. Personally, I don't think it can. I'd call it strength of mind.