Yeah this has been on my mind for a while actually. My nan's old house in Rugeley had a really active period back when my uncle and his wife were going through a rough patch and staying there - objects moving, cupboard doors, the usual stuff. Settled right down once they sorted things out or moved on, can't remember which.
I've seen a few researchers suggest its linked to emotional energy, like the tension creates some kind of trigger or fuel for whatever's already present. Whether you buy into that depends on your model of what poltergeists actually are I suppose.
The tricky part is separating cause from effect. Like, are the incidents actually increasing, or are people just more primed to notice and report them when they're already stressed and on edge? That's the bit that's hard to rule out without proper documentation over time.
Anyone kept any kind of log during a stressful household period? Would be really useful to compare notes on whether the activity tracked specific individuals or just the general atmosphere of the place.