I think that everyone can over-come depression, with the right help. It only takes one person to extend their hand and take yours.
A little about myself: I have been a self-injurer for 4 years, suicidal more then that. I try to help whoever I can, even if I think that they are beyond help, or do not want it. I hope that some day someone will reach out and help me. Until then, I will keep helping people try to over-come their depression.