The following is from the website Dictionary.com:
par·a·noi·a [par-uh-noi-uh], noun
1. Psychiatry. a mental disorder characterized by systematized delusions and the projection of personal conflicts, which are ascribed to the supposed hostility of others, sometimes progressing to disturbances of consciousness and aggressive acts believed to be performed in self-defense or as a mission. 2.baseless or excessive suspicion of the motives of others. Also, par·a·noe·a [par-uh-nee-uh]. Origin: 1805–15; < Neo-Latin < Greek paránoia madness. See para-, nous, -ia
Here’s something else that the editors might have added to the above definition:
3. The characteristic of being so absurdly and maniacally obsessed with a single public policy issue that one deludes oneself into believing that every other policy matter pales in importance and, indeed, that advocacy surrounding all other matters is really part of a conspiracy to target one’s issue. 4. The belief that millions of good people should suffer in the shadows so that it can be assured that a few thousand souls can purchase and own mass killing machines without meaningful regulation. See for example: The American gun lobby.
If you think this is an exaggeration, check out the following news item: