I have had this feeling for many years. I am very much paranoid most of the time. Sometimes, I do feel a bit manic and would "act" for whoever is watching. My docs take this as a paranoid delusion, and seroquel seems to help make it go away.
Thats interesting, I've been prescribed Seroquel (quetiapine) for a totally different thing. Although the side effects of this are really annoying me. I'm on 400mg a day, but sometimes I just take 300.