I like to say that the brain is very good at adjusting to adversity, but apparently very bad at adjusting to it's absence. I've heard that people who went through the Great Depression (unrelated :-), tended to spend the rest of their lives hording supplies.
I think it's well established that negative experiences impact most people more highly than positive ones, even if logically they are of the same degree. Based on your conjecture I suppose this would simply mean this lingers, informing the brain how to react in the future.
Yes. Anyone who has had to handle the affairs of someone in that "greatest generation" who has passed away knows, the amount of stuff they have accumulated is immense, almost overwhelming.
It was a charming part of their lives (e.g. going to see all 7 of grandma's prized typewriters in their basement), but trying to sell those 7 typewriters on ebay only to just give up and have some estate sale person come through and basically pay a small portion of the value of things just to get it off your hands is the only option.
I believe my grandma, who survived the war, never threw away any glass jar for similar reasons. It was also hard to convince her not to eat molded food.
Not sure about hoarding specifically, but depression can definitely cause similar outcomes. It usually causes a lack of motivation, resulting in many consequences ranging from procrastination up to neglect of personal hygiene and of course keeping things tidy. Pair this with a potential shopping addiction or something in that vein and the differences start to blur.
