Paranoids are easy to create and feed if you know how to flatter their egos: "He picked me. I must be on to something." The basic level of fear created is helpful, since most of us like a scare, and if it seems to be real, the funhouse (or spookhouse) illusion is complete. All that is needed when this is accomplished is to keep the frightening "insider" info coming in small doses. At this point, your target is basically a puppet and mouthpiece, ready to infect others with carefully crafted disinfo, which of course is mostly true, but injected with a small amount of ear-tickling lies.
If paranoids are easy to create, consider how childishly simple it is to create a True Believer.