Sharing a little personal info but my ex wife is diagnosed bipolar, schizophrenic, manic depressant draws a check and stays in and out of units all the time. I'm talking about a beautiful woman who had schollys and graduated most likely to succeed made 29 on the ACT. The mind is a VERY powerful thing that most people don't have a clue about. Your imagination can make you hear things, see things, etc. that nobody could convince you differently of.
I understand your point on the mind being able to play tricks on you. However, what happened in my old house took place over 30 years and affected most of the people who spent any amount of time in that house. Many, actually most, had no idea there was anything out of the norm with the house when they saw, felt, or heard what went on in there.
Plus there is the matter of how pictures would be removed from the walls and arranged on the floor. Or the nights I'd lay in bed listening to drawers & doors opening & closing (quite loudly, btw) for what seemed like hours. Some nights, instead of the drawers, they'd open a closet and simply push clothes back and forth along the rack, almost like they were looking for something to wear. There were things that went on in that house that cannot be explained by simple tricks of the mind.