i've lived with depression for almost 3/4 of my life. there are a few things out there which have been known to help fight drug resistant depression; but before that, and after counciling, cognitive behavioral therapy can usually be of at least some benefit.
personally, i've developed my own life philosophy based in hard science and logic, which has helped me. but i kind of figure, as with beauty, content peace of mind is unique to the individual, and the fight for something unique to each individual will be as unique. like anything worth doing, it isn't easy, but you'll develope the skills you'll need, with or without the help of drugs or therapies or other people (like the development of skills, to do with or without help is up to you), to build your own content peace of mind.
all the while it's important to know that the highs life has to offer are higher from the perspective of one who has been to the bottom, and no highs can exist at all for one who has experienced no lows.