PARANOIA

[noun] - an extreme and unreasonable feeling that other people are going to harm you or that they have a bad opinion of youThere's a lot of paranoia about crime at the moment. [U]I promise you it's not just paranoia - someone has been following me. [U]I'm fed up of all your stupid paranoias. [C](specialized) Someone who has paranoia has unreasonable false beliefs as a part of another mental illness, for example schizophrenia.