I have experienced situational depression during a divorce some years ago now and the subsequent transsistions to a new way of life. I am not, however, prone to chronic or chemical depression.
I agree that those involved with a depressed person are powerless to really make a difference, aside from basic empathy & kindness.
I also agree that sometimes the wisest choice is to get away from that dysfunctional person especially if they are not taking any steps towards recovery.
I also thing that a whole hell of a lot of these issues are about people using depression or other neurotic emotional problems as a means of controlling those around them.
Being a ‘victim’ and building an entire identiy around ones depression/illness is a very effective method of controlling others through manipulation.
I think most depression/anxiety is symptomatic of a person needs to make some changes in their life, spiritual life, and attitudes, notwithstanding true bio-chemical dysfunctions.