Paranoia

Paranoia is an excessive anxiety or fear which is considered irrational and excessive, perhaps to the point of being a psychosis. This typically includes persecutory beliefs concerning a likely threat. In the original Greek, παράνοια (paranoia) means simply madness (para = outside; nous = mind) and it is this use which was traditionally used in psychiatry to describe any delusional state. However, the exact use of the term has changed over time in medicine, and because of this, modern psychiatric usage may vary.