As someone who really battled depression in my 20s, I can relate to this. Ultimately I won my battle partly by pretending to be happy. Mostly because this created opportunities for authentic joy by allowing me to be around others in a positive way. Perhaps this is similar to what you refer to as "active indifference," it was definitely a resistance to the pull to accept the darkness.
I do have to say for me it did go away: I am one of the most content people I know. I weather setbacks and bad news better than most. That is probably partly that is attributable to remembering the darkness and being so glad that I am now in the light.
If you are still struggling, my heart goes out to you.