On Disidentification. Hi Posty,
I"m going to come at it maybe from a slightly different direction, maybe it speaks to what you are pointing at, maybe not…
So we have ideas about who we should be, based on social norms, temperament, position in a social context etc...Then we can compare those ideas with how we percieve ourselves to actually behave, and evaluate ouselves based on that.
In case of depression, we might have the idea that we should be happy (based on social norms that we have internalised etc), but we are feeling depressed so we think we aren't really living up to that standard, which creates another layer of mental anguish.
So one feels bad because of depression, and on top of that you feel extra bad because being/feeling depressed is not what you should be/feel.
So what I take your 'identification with depression' to be in this context is the adjustment of the ideal self to be more in line with the actual self. There is adjustment of goals, expectations etc so to avoid feeling extra bad about not meeting the standards of an unadjusted ideal self. This might be a good strategy in the beginning, and indeed even necessary to not make things worse... it may even be an overall good thing because social standards are at times absurd (nobody is happy all the time). But if I understand what you are saying, it may also be the cause of staying more depressed because that's what you come to expect (identify with).
I'm not sure what the solution is here, because it would seem to disidentify you would need to build up an ideal self again that doesn't take depression into account, but then that runs the risk of backfiring if you happen to feel depressed again…
Maybe the solution is to not evaluate yourself on the happiness axis alltogheter. It doesn't seem like a goal that we have all that much controle over anyway… and more of a byproduct of other things most of the time. The whole 'wisdom is changing what you can't accept, accepting what you can't change and knowing the difference'-thing. I do believe that some things just go away if you focus on other things…. and not by trying to not focus on a thing, attention doesn't seem to work that way.
Another thing that might help is the more general realisation that thoughts and identification are allways only mere abstractions. And abstractions are necessarily crude simplifications of what's really going on, and never the whole story... sort of a deflationary approach to though in general, so you don't take it so seriously anymore, either way. That's why they sometimes call it the chattering monkey in eastern philosophy, to reduce the importance it is typically given.