What is true is already so.
Owning up to it doesn’t make it worse.
Not being open about it doesn’t make it go away.
And because it’s true, it is what is there to be interacted with.
Anything untrue isn’t there to be lived.
People can stand what is true,
for they are already enduring it.
—Eugene Gendlin
It seems to me - and I'm a depressive - that even if depressed people really do have more accurate self-assessment, your third option is still the most likely.
One recurrent theme on this site is that humans are prone to indulge cognitive biases which _make them happy_. We try to avoid the immediate hedonic penalty of admitting errors, forseeing mistakes, and so on. We judge by the availability heuristic, not by probability, when we imagine a happy result like winning the lottery.
When I'm in a depressed state, I literally _can't_ imagine a happy result. I imagine that my all plans will fail and striving will be useless.
This is still not a rational state of mind. It's not _inherently_ more accurate. But it's a state of mind that's inherently more resistant to certain specific errors - such as over-optimistic probability assessment or the planning fallacy.
These errors of optimism are common, especially in self-assessment. Which might well be the reason depressed people make more accurate self-assessments - humans as a whole have a cognitive bias to personal overconfidence.
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But it's also inherently more resistant to optimistic conclusions, _even when they're backed by the evidence_.
(It's more rational to be accurate and sad than delusional and happy - because happiness based on delusion frequently crashes into real-world disasters, whereas if you're accurate and sad you can _use_ the accuracy to reduce the things you're sad about.)