What's the difference between self-pity and depression in terms of recognition and (non- drug) treatment?

This information would seem useful personally and in relating to others. One might be a better friend by dispensing a swift kick in one case but in a different case that swift kick could be devastating. Also, I've noticed that whereas vulnerability is closely associated to loveableness, there are also those who seem , consciously or un-consciously, to cultivate an air of vulnerability which is effectively manipulative. Again, I'd like skills in recognition and response, both in oneself and in others. Suggestions?

: http://alcoholdrugstreatment.info/whats-the-difference-between-self-pity-and-depression-in-terms-of-recognition-and-non-drug-treatment