Ideally? I should say that she could be the one, and maybe try working things out.
Real world? I support the two above posts 100%. My ex girlfriend was VERY VERY similar to your friend - 26ish, met at work, mental issues, long history of depressant medication, hospitalizations, moved from another area... SCARY how similar my experience is, only I wasted 4 years of trying to make it work. Yes, I am an idiot - learn from my mistake and drop her, or proceed with extreme caution.
She's leaving the area? You already have issues with her? Keep looking, date others.