How is paranoia defined, and what are the symptoms to look for?

Needs a professional: There spectrum between suspicious and paranoid, between doubting, skepticism, and pessimism and downright loss of touch with reality. No one, not even a psychiatrist, can self-diagnose paranoid delusions. That being said, some symptoms include feelings of being spied upon, tracked, or followed, and feeling like people "have it out for you" or are "out to get you" to an unjustifiable degree.