I whole heartedly agree with Anna342 on everything, truly. Please seriously consider everything that has been said in this post.

1. We cannot diagnose, unless trained, no one else should be either.
2. You can be supportive by suggesting help, getting her in touch with someone who is trained, and by being there for her as a friend most definitely.

It is not easy to sit back and watch if she chooses not to seek help but that is her decision and can't make it for her; we can only encourage and be supportive. By posting is a sign of what a good friend you are and expressing your concern. She is lucky to have you.