"Decades later, in response to a Freedom of Information petition, the F.B.I. released its Hemingway file. It revealed that beginning in the 1940s J. Edgar Hoover had placed Ernest under surveillance because he was suspicious of Ernest’s activities in Cuba. Over the following years, agents filed reports on him and tapped his phones. The surveillance continued all through his confinement at St. Mary’s Hospital. It is likely that the phone outside his room was tapped after all.
In the years since, I have tried to reconcile Ernest’s fear of the F.B.I., which I regretfully misjudged, with the reality of the F.B.I. file. I now believe he truly sensed the surveillance, and that it substantially contributed to his anguish and his suicide."
An interesting question: how would you help a friend who was paranoid *and* right about it?
Unsurprisingly, I have an answer to offer for my hypothetical question.
For the purposes of this answer, let us assume that the person is not in immediate physical danger.
When I want to help someone, I play to my strengths. I harmonize, in the Aikido sense. If I am offering support or advice to someone who is delusional in some way, I restate in a neutral voice what they are telling me, to confirm I am hearing them correctly (active listening). Then, if doing more than listening seems appropriate, I try to help them reason through what their response should be. I do not attack the person or try to impose my own perceptions on them (unless perhaps they explicitly ask me to, in which case they are probably already making progress working it out for themselves). At most, I might share with them my philosophy that we should maintain a healthy skepticism of all inputs, even those from our own senses, and that this skepticism should be grounded in an understanding of how those senses operate (they have specific, known limitations, and that's okay).
In other words, if an insane idea or perception is driving someone crazy, help them make a sane response to it. Don't fight them; help them find their own strength.
1. sadly, I am not certain if there's a way to link to a NYT article that won't eventually break from NYT's own foolishness: http://www.nytimes.com/2011/07/02/opinion/02hotchner.html?pagewanted=all
2. because the ability to answer hypothetical questions is one of my most bothersome superpowers...