Narcissism and Sam Vaknin
Vaknin is an Israeli with a considerable record of dishonesty and dubious scientific qualifications. He describes himself as a narcissist and purports to offer an understanding of that syndrome.
His descriptions of what narcissism is and the explanations he offers for its emergence in people are recognized as authentic and helpful by many who view his various videos
So what is the scientific status of his theories? From my viewpoint as a psychometrician, his theories have no standing at all. There is no objective measure of narcissism as he describes it nor is there any way of measuring degrees of it. So his generalizations are untestable. It is essentially waffle -- a theory so broadly specified that most people probably see something of themselves it, rather like horoscopes
My initial suspicion on reading Vaknin was that he was probably talking about a number of traits rather than a single trait. And the available scientific literature on narcissism bears that out. Sigmumd Freud was the effective originator of the idea of a narcissistic personality in 1914 so Vaknin comes rather late to the game. There are in fact a number of indexes of narcissism in existence so if there is a unidimdensional trait there, we should know of it.
And a 1991 study by Paul Wink was very informative about that. He combined three existing measures of narcissism, including the MMPI and CPI, and factor analysed the responses of a heterogeneous sample to them.
The sample responses showed no such thing as as unitary trait of narcissism. Varimax rotated eigenvectors revealed two distinct traits underlying the "narcissism" questions: Vulnerabiliy and grandiosity.
The statements surveyed would seem to be at least as comprehensive as the symptoms described by Vaknin but in the absence of a measuring instrument produced by him, we have no alternative source to analyse. So it seems likely that Vaknin's picture of the narcissist is fiction. The traits he describes do exist but they do not form the coherent syndrome described by him.
So Vaknin would seem to be a popular guru like Krishnamurti, Gurdjieff, Madam Blavatski etc. His pontifications make some sense to some people but he is essentially describing something that does not exist. Gurus have their place in helping people makes some sense of their world but their claims should not be regarded as scientific or reliable in any way.
Summary: Delusions of grandeur exist in both clinical and sub-clinical forms. What goes with such delusions is the issue. Vaknin is not alone in seeing many other traits associated with it but Wink's finding of strong separability between Grandiosity and Vulnerability has become widely accepted. Characteristics that co-occur in Vaknin himself may not co-occur in others.