Well it might of started small, maybe a few noise's in your house that were totally explainable, then you might of thought "Maybe it's a poltergeist"
Then small things might of started moving around. Then you might of thought "It might actually be a ghost" And it got worse from there.
If those two sentence relate to your situation, you created it yourself by believing that it was there.
There is anothery story about one called "Quick silver" Who does all times of things and write's a Q on every mirror in the house and then she moves on.
If the spirit isn't harming you, why must it be run out of the house? As long as you don't fear it, you'll be fine.
I'm sure he isn't moving things around for the hell of it. There are four main reasons why a spirit begins to "haunt". The first is an attempt to communicate. The second is because they have denial issues pertaining to their death and don't believe they're a spirit and that you're just ignoring them. Three, they feel the need to make their presence known. Or four (and least likely) they are malicious and attempt to cause fear, which facilitates more energy for them to use to manifest more strongly.
A "poltergeist" is nothing more than a spirit that has enough energy to manifest or move things. You probably live on ley lines or have someone in your home going through puberty or who is extremely emotional. Especially girls who enter puberty have more cases of poltergeist activity surrounding them.
If you feel the need to do something, protect your bedroom to block out any spirits from entering. Protect yourself with a physical object/amulet.
If the spirit shows signs of violence and only attempts to provoke fear THEN exorcise the house. There is a big difference between exorcism and banishment.
A priest will do nothing. When I was a child, my step father called priests (different ones) on multiple occasions and I swear the spirit just laughed, because things only grew worse, until my mother performed her own exorcism on the house and cleansed it of all residual negative energy.
Zei, sort of like what Raven put, another theory is that they are forms of energy that are created by negative thoughts and emotions that are built up. The thoughts and emotions of someone going through puberty, some other stress, were in war, or something of another is built up and kept in the subconscious. It creates a thought form or being that is strong enough to move physical things as a way of letting out I guess.
Another thought is that the troubled mind cause psychokinetic powers to be activated and used subconsciously. The other is that it is just a ghost that is strong enough to move things. "noisy spirit". So there are many thoughts on what a poltergeist is. I would still recommend therapy because something negative that a person is holding in could be feeding it. Could help calm you and get you back in control of the situation.
If it does happen to be a poltergeist, a traditional remedy is to use the plant 'broom'. In the olden days witches tied this bush to their staffs. You can do this yourself, using it to cleanse the area by mindfully sweeping, or you can use some broom as a cleansing smudge stick :)
