"...Karl Jaspers was the first to define the three main criteria for a belief to be considered delusional in his book General Psychopathology. These criteria are:
- certainty (held with absolute conviction)
- incorrigibility (not changeable by compelling counterargument or proof to the contrary)
- impossibility or falsity of content (implausible, bizarre or patently untrue)"
"Megalomania (from the Greek word μεγαλομανία) is a historical term for behavior characterized by delusional fantasies of wealth, power, genius, or omnipotence - often generally termed as delusions of grandeur or grandiose delusions...
...Delusions of grandeur may be seen as distinct from megalomania: An overweening and excessive preoccupation with one's own importance, though it may be considered pathological, is not necessarily delusional. A delusion of grandeur, if it is a true delusion, must meet the psychiatric criteria for delusion." ...από τη Wikipedia.
Mass Delusions and Hysterias - Highlights from the Past Millennium (Bartholomew & Goode, από το CSI)