To cut a short story shorter, I'm not entirely sure how to use the word "paranoia" in relation to a specific subject. That is, if one is paranoid about the government, would they have a paranoia "over" the government, a paranoia "about" the government, a paranoia "concerning" the government, or something else entirely?
Here are several ways of doing it:
1a He was paranoid about conspiracy theories.
1b He was paranoid that the IRS would audit him.
Notice that in both sentence, you could substitute afraid in place of paranoid.
2a He had a veritable paranoia about conspiracy theories.
2b He had a veritable paranoia that the IRS would audit him.
Here you could substitute fear.