That we can look at the lives of millions of people in America in 2021 and call their abject misery 'maladaptive' or 'overlearned' is ghastly. I know I'm supposed to offer more in an HN comment, and I'm not trying to call you names. But if I told that to someone in psychotherapy I'd deserve more than just losing my license.
I don't doubt that looking inside people's biology for clues about what's going on when they suffer these kinds of anguish is interesting or potentially helpful, but I can say two things quite confidently on the matter:
1) After 60 years of dominance, the biological-psychiatric project's track record is dismal and has failed to move any population-level needle on the levels of suffering it tries to study and ameliorate
2) Focusing on biology at the expense of questions about "context" or "environment" or "maybe this depressive is reacting exactly appropriately to their horrible existence" is a staggering waste of brainpower and money and time, and it leaves me at a loss for words. Outside of the social strata represented on HN (and probably within it to some degree) the world is "threatening, unrewarding, and pointless" for vast numbers of human beings, and I'd challenge anyone to sit in front of such a person and tell them to their face that it isn't. If there exist "regular experiences which should falsify those beliefs and lead to learning (but doesn't)", I got news for you: those experiences aren't prompting "learning" because they're not enough. This is like telling hungry people to feel more full after feeding them a saltine cracker.
You can't "cure" depression by pumping people full of prescribed psychotropics - the major mental health effort of the past half century - any more than you can do so by pumping them full of vodka. Address poverty, address violence, address a litany of social ills - and I mean really address them - and you'll see what happens to depression.
Excuse me, but this touched a nerve.