Anyone here ever read the book 'Night Chills' by Dean Koontz? The central theme is mind control-related--something is introduced in the water supply of a small town, and then if someone utters a certain trigger phrase to a person that has ingested that water, they have total control over that person's mind. I first discovered it in one of my seventh grade study halls and it disturbed me really bad at the time, mostly because of all the amoral things these corrupt people who had developed the technique would do with their power.

Never heard of this, sounds like a neat thriller.