I had it as a one off mid life crisis thing so I wouldn't meet the criteria, it stopped after a few years and never returned, but I used to ask the voice for proofs of what it was saying, those proofs never came, so I could half-see through it, not completely because it establishes a rapport bond, something like a mesmeric/hypnotic thing that makes you find it more credible than you normally would, sort of like how in a hypnotist show people automatically believe what the hypnotist is telling them, if you can establish doubt in your mind you can throw it off eventually. I came to find it a vampiric thing as though it was coming in for a feed.