> My totally amateur pet theory is that paranoia is threat pattern recognition gone bonkers.

Supposedly OCD is your brain’s cause-effect loop being too potent. As in, you have a random fear I.e. “stove is on, fire will burn down house,” you go to check the stove, and the act of checking (regardless of its being on) creates the feeling that you saved your house from burning down, so now you feel compelled to check every time. Paraphrased from the Huberman podcast.