i was in a situation where i had a very close friend who was going through depression as well. At first, it seemed like a life saver because it felt great to talk to someone who understands what you're saying. however, as time went on, and i talked to my therapist about it, it turned out that--as jamiee has mentioned above--we were at different stages. i became a crutch for her and she began to need attention from me all the time because she was NOT actively seeking medical help, she believed that it would not be of any help to her. I, on the other hand, began feeling responsible for her well being, which I later realized is not my responsibility. It became a difficult juggling act, trying to be supportive without taking on her burdens, as well as trying to move forward and not sink back into depressive thoughts after conversations with her. We eventually stopped talking after a massive projective breakdown on her side. I did not try to reestablish communication because I had come to realization that if she was going to get better, she needed to learn to do it on her own terms, her own time, and in a self-motivated way. Had we been more conscious of the fact that while our roads may have seemed similar, they were not in fact, the same, we might be on better terms. We recently started talking again, but it is strained. From my experience, I learned that it is important to limit how much of the friendship is based in the common ground of depression, otherwise, it may become the only thing holding it together, which seems unreliable and extremely difficult to manage, considering you can't know which one of you might pull out first and how it will be handled. A close friend can be an incredible ally, however, I would advise being cautious and conscientious of the dynamics of the relationship and how they change.