I copied this from one of true-lilly's posts.
From Wikipedia, the free encyclopedia
Gaslighting is a form of psychological abuse characterised by persistent denials of fact which, over time, have the effect of causing the victim to become anxious, confused and progressively less able to trust his or her memory and perception. A variation of gaslighting, used as a form of harassment, is to subtly alter aspects of a victim's environment so as to cause discomfort. This technique is supposed to have been used by the Manson Family on their 'creepy crawler' burglaries, in which nothing was stolen but furniture in the house was rearranged. 
The term was coined from the 1940 film Gaslight and its 1944 remake in which this technique is perpetrated several times on the main character. The classic example in the film is Gregory turning on the gas lamps in the loft which causes the rest of the lamps in the house to dim slightly; when Paula comments on the lights dimming she's told she's imagining things.
It's nice to know that this term is actually definable in Wikipedia.
Personally, I can attest to this manipulation and the psychological discomfort it causes, but it is only one of many "techniques" that I am targeted with.
I have, to the best of my ability, since it began, attempted to disallow these "infectious" creatures the capability to cause destabilization, but I am one against many.
Most importantly, is how they are able to enter a home without leaving a trace or appearing to be an intruder.
I have always suspected it must be someone familiar with my house; someone who looks like me (double); drives the same car, etc. Perhaps living in the neighborhood. I don't have the answer, but I suspect they would like me to believe it is a family member. This would be worst case scenario.
I have memories of this occuring within my home as a child.
P. S. I am enjoying the read, true-lilly!