We discussed the Orthodox response to suicide several months ago. This
might answer some of your questions. As I understand it (and I'm only a catechumen so take what I say with a grain of salt), Orthodoxy acknowledges that depression can be caused by a medical condition. But Orthodoxy understands that sin can also cause depression. An Othodox priest would not be hesitant about referring a parishioner for psychiatric treatment if it was needed.
As it's been explained to me, Orthodoxy allows an Orthodox funeral if the bishop believes the individual was suffering from mental illness.
ETA that "this" points to an article. I realized it doesn't really show up as a URL link. Sorry.