For people interested in explanations of depression that's more than "It's an imbalance in brain chemistry" I recommend looking at the work of Lisa Feldman-Barrett. She explains how brains work¹ in computational & evolutionary terms & it's a lot better than the typical reductionist explanations in terms of chemical imbalances.

¹https://www.youtube.com/watch?v=KliAI9umFyY

I think they got us good with the imbalance of brain chemistry back in the 90s when Prozac was all the rage. Prozac was the Ozempic of the era with the financial incentives to make it so. The patents have subsequently expired so it isn't the cash cow it was. Odd how the science that went with it has now been discredited.