I don't think those who are depressed are anything of an interpersonal lost cause. Talking to people (forums rather than one-to-one, at first) helped me at my lowest. It gave me a chance to be passionate and creative at my leisure and then receive recognition for it. Then singular people became interested in me, and that took things to a new level: I began to feel a sense of giving that I found very rewarding, and there's something deeply beautiful and esteem boosting in the thought of someone having the time just for you. That you're worth someone's time with no ulterior motive (except perhaps the reciprocated joy of connecting with another); I hadn't believed that before, and then I got proof. I suppose I have the internet to thank for that.
I think if anything can help, it's connecting with good people. The people of Holism, the altruists. And simply the optimists; those who can emphasise the good in others. It's infectious.