For what its worth, I would advise against taking the test. This would be my DD reasoning in such a scenario. If you agreed I would first feel elated because I was so close to the truth. The truth I could never find or prove, the elusive truth that was making my life a complete nightmare. And here you are offering me the Holy Grail, a polygraph test, a truth that cannot be refuted. Even assuming polygraph tests were 100% reliable, if you took the test, in the end, after the initial comfort provided by your willingness to subject your self to such a test, I still would not believe you. Even if the results showed that never once did your heart rate increase (whatever the measure/measures are), my conclusion would be that you were more masterful of a deceiver than I had ever imagined. So artful, that you could even fool the machine, just like you’ve always fooled me. I would have to be more vigilant than I had ever been before to catch you in your perfidious ways. At least that would have been my reasoning, when I was fully in the grips of the delusional thought process. The way I see it is, if he is aware he is delusional and questioning his delusions, then he shouldn’t ask for such verification knowing that everything only leads to more doubt and more questions, if on the other hand, he fully believes and accepts his delusional thought process, then the only thing that will occur is more doubting and more questioning. I truly believe, until a DD person accepts, really and truly accepts that it is ME, and not you, and not the world, but ME who has the problem, then there is no helping them disprove the irrationality of their thought process. Because until the person reaches that point, their thought process isn’t irrational, it’s perfectly rational and normal, its just so happens they are very unfortunate victims, because they are not crazy, and everything, everything they believe, can really happen, and has, and is. I don’t know, this is just my experience, but I believe it would only add fuel to the fire.