They're both prepositions in this case. about means on the subject of; in connection with. of mentions somebody/something that a feeling relates to (the feeling in this case is paranoia) Hope this helps.
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Willians Batistelaparanoid of flying."I would never use this expression. I'm surprised to see it. Everyone I know says "paranoid about". I think the writer was confusing "paranoid" with "afraid", because there's the phrasing "afraid of".