Indeed. It’s really sad how it happens: someone’s depressed and is either too sad or irritated to be able to, or want to deal with anyone, which pushes people around them away—people who are in the best position to help them. Worse, while the depressed person can do something about it, the depression makes it hard to do anything about it! The path of least resistance is just to let people be repulsed. However, the path of least resistance leads downhill.
Divining the forces of depression (and in my case, the vagaries of bipolar disorder) is already taxing enough for myself, let alone for anyone around me who has no idea what’s going on in my mind. Hence, I understand why someone would give up on me. It’s not their fault, and I understand that. There’s only so much people around me can do, and if my condition lightens up, it’s on me to reach out, let people know that I’m better at the moment. And if I can, alert people whenever things are turning for the worse.
Having said all that, I’m not sure I understand what you meant by the latter part of your 2nd paragraph.