Cool post Machiavelli, I wonder if Narcissists realize their condition on a fundamental level or whether they think that by admitting it they're somehow above it. I didn't look very carefully into the actual research so I'm not sure how they conducted the business, but if they first asked whether the test subjects are narcissists or not and then conducted the test, they would be answering all the questions based on their first answer. A little bit like how everyone answers these topics based on the first assertive reply (if they read the replies before reading the main post).
I wonder about narcissism in general, I don't think it necessarily comes from an insecurity. Being narcissistic can drive you to do things. It's a motivation among others. While one could say that narcissists try to compensate for lack of intrinsic self-worth, one could also say that the people who dislike bragging or putting themselves above others try to compensate for lack of success.
Everyone has their own path to walk and everyone should find their own answer to how they want to live their life; I've been both arrogant and modest and personally I feel happier being modest and appreciating other people. But that's just me.
I have met a few that I am sure would be diagnosed NPD if chance was given. They do know what it is, they work in health care, one doctor, one RN.
I have tested them a bit and they react very strongly to some common things those people react to. They have also very much presented a grandiose ego and a lack of empathy.
I do not think any of them would admit even to themselves they are narcissists. It seems like their take on it is that they are simply just smarter, better and more worthy people. And that others are no smart, good or worthy. I do not think they ever reflected something is wrong with THEM. They just think things are wrong with others.
They are indeed nasty creatures, maybe self aware narcissists are better, but I have only came across them online, which makes me wonder if they exist in any larger quantity IRL.