I'm enjoying asking hypothetical questions these days!
Okay, here's a scenario, tell me what you think the shrink should do.
A patient comes for an evaluation. He's seen a psychiatrist before, but he stopped going because the psychiatrist diagnosed him wrong. Total idiot, that doc. It's clear this diagnosis is meaningful to the patient, and the meaning is very negative. The patient isn't in a place to hear that this is the problem (fill in the diagnostic blank however you'd like). The new shrink does a careful evaluation. He listens to the symptoms, he listens to the course of illness, he gets info from any outside sources the patient wants him to consult. He doesn't call the last shrink because the patient doesn't want him to: the patient doesn't want his diagnostic thoughts colored by information from that idiot, and the new shrink is okay with this. However, the new psychiatrist, with the data he has, has come to a diagnosis: the patient has what the idiot doc said he has. If he tells the patient this, the patient will be gone (yet another idiot shrink)-- the psychiatrist may be "right" but what good is that if he can't help someone who won't come for treatment? So what should the new psychiatrist tell the patient about his diagnosis?