Is is that crazy to think that a wild swing in steroid hormone levels can lead to depression - similar to what we observe when men come off of steroid cycles? If so, is something like post cycle therapy for women recovering from pregnancy really that crazy of an idea?

I don’t know enough to speak intelligently about the underlying biology, but an interesting theory I heard from someone more knowledgeable than me is that the sudden drop in progesterone - which tamps down neuroinflammation - sends the microglia (immune cells of the brain) into overdrive which results in rapid destruction of neural tissue which is experienced by the patient as profound feelings of unhappiness / depression. This is not unlike the runaway inflammatory response that kills people with COVID — which is why dexamethosone (an immunosuppressant) reduces mortality.