It appears this person's high intelligence helped them cope with an otherwise very hard to treat condition.
> It is not important to know where the voices are coming from. It had just been demonstrated to me that prior to turning around I did not know their origin, and yet I was comfortable having taken on the “mere belief,” and as it turned out the false belief, that nobody was there. [...] And after I was forced to change my belief, it was still fine.
Author explicitly attributes it to support network instead. Are you very confident they're wrong about this important aspect of their own life that they have obviously considered carefully?