So 4 years later, when they posted a follow-up reporting that they'd taken the antidepressants and got their life back together, I read it with a mixture of vicarious happiness but also dismay. The choice to accept medication seems like a betrayal of that earlier evaluation. Were they wrong? Was the problem their head rather than their circumstances? Their new self thinks so, but did that come at the cost of sacrificing their old mind? It really depends on when they were most able to clearly perceive their situation. When were they most objective about their mental state and life problems?
I'm the user in question; a friend called my attention to this post.
I think you're making a category error here.
Circumstances being 'good' or 'bad' is a proxy for how they affect (typical) people. 'Bad' circumstances make most people feel bad. 'Good' circumstances are those that make most people feel good. Joy and misery exist only in the mind (and perhaps, in some distant future, in some description of brain-state that is currently beyond medical science).
That connection between circumstances and feelings isn't necessary or a priori and obviously some people have atypical responses to things. For example, being on a very long bus trip would be very boring to most people, but is exciting and invigorating to me. Similarly, a busy social environment is exciting and invigorating to most people, but very stressful to me (or at least to past iterations of me with higher anxiety levels).
My circumstances were bad, in the sense that they would make a typical person feel worse than they otherwise would (and indeed I did feel much better when I was lifted out of them). But that wasn't, fundamentally, the problem. The problem is that I was depressed, and that that depression was sapping my strength to do anything about it. My circumstances were not helping, but the problem was my state.
You're thinking of circumstances as a thing that "should" make you feel good or bad, in the sense that if you're not feeling good in good circumstances or bad in bad ones that you're being somehow dishonest. But in just the same way that the physical property "reflects 450 nm light" is not the same as "experiences the qualia 'blue'", bad circumstances are not the same as "experiences the qualia of depression". Your mind is a territory all its own, which is affected by (but is not the same as) the territory of the world in which you live. And your goal is to improve the quality of your mind-territory, which can be helped by (but is not determined by) the world-territory. You're colorblind and trying to tell yourself that obviously red and green are two names for the same color, that anyone saying otherwise is lying, and that putting on those colorblind-curing glasses is "stopping you from seeing the world as it really is".
Or put more simply in the language I think of it internally: you feel depressed first, and then (subconsciously - on a conscious level this feels like "just seeing the world for what it is") find ways to justify it. Your subconscious filters find bad things and filter out good ones; your subconscious judgements shift in the direction of being incapable and weak. And as you slide deeper into depression, the persistent failure that often accompanies such a descent justifies, reinforces, and intensifies those filters.
Their new self thinks so, but did that come at the cost of sacrificing their old mind?
One of the things I was struck by is how (at least in terms of subjective experience), I didn't "stop being me". The essential pieces of my identity, my values and likes and so on, didn't change. The relative position of experiences mostly stayed the same (modulo some things that feel better because they were tainted by heavy anxiety) - but their absolute valence got tremendously better.
It may help to recognize that even when I went back to being depressed shortly later, this evaluation remained the same. Depressed me wanted more than anything to get back to the position of not-depressed-me, and found some motivation in trying to do so. I didn't know how to find that place in my mind, but now I at least knew it existed, and I devoted what little self-improvement-energy I had to trying to find my way back to it. I had a destination, if not directions by which to arrive at it. And today I find myself in its vicinity, trying to nail down the pieces to keep myself there more stably.
Depression, being a disease of the mind, has access to everything you do. It will use your values and knowledge against you. If you're religious, it will convince you that you're miserable because you're a sinner. If you're a devoted animal rights activist, it will convince you that you're miserable because you didn't save enough puppies today. If you're a rationalist, it will convince you that you're miserable because that's the Facts And Logic Way To Feel.