oldbatty Good question!
I get it from the psychology text books and the psychologists I still meet who talk about research in the field. There was a lot of debate about whether it was appearing to have become more widespread simply because we are better at identifying it (the same debate happened with dyslexia) or whether there is an actual rise in it. Sadly an actual rise seems to be the truth. TV, Pop and Screen stars, "The Real Housewives" all giving the "I want it all and I want it now!" attitude. Also Teachers having a much tougher time with pupils being disrespectful. The attitude of "I am entitled to ..." was measured in a study. It is very strong, taken in cohorts of ten year groups, older people said they expect to work for what they have far more than younger people said it! Also older people came out with expecting to be famous for doing or achieving something at a special level, younger people were on the side of being famous "for being me".
The diagnosis of Narcissistic Personality Disorder, which is Narcissism in its extreme form, has specific criteria from which the diagnosis is made. There are many criteria, such as "Has a grandiose sense of self-importance" and "Believes that he or she is “special” and "Lacks empathy" and "interpersonally exploitative" and "Has a sense of entitlement". Plus many more. To be diagnosed of any personality disorder though, a whole set of separate criteria has to be met before the specific disorder's set of criteria is looked at.
We are not saying though, that Narcissism in society or in general has risen to pathological levels, but that traits of Narcissism are much higher today than they were in previous generations. There has been research into this, forgive me, I can't go and find it now (time constraints) but I can find at least one book before I post this message.
I promise that I do not make any statements without having the evidence to back them up.
If I just feel as if something is a certain way I make it clear that I am only giving my own feelings on the matter.
Regarding Narcissism, I have been doing some voluntary work on the subject, both with research and with people affected by it. This is why I made the comment.
Diagnosis of Narcissists is not that common as a direct diagnosis because Narcissists do not turn up at the clinic! Why should they? They think they are wonderful! - Better than everyone else in fact! The phrase "they act as if the world owes them a living" is quite apt. I did know one who went to his GP and said "I appear to be having trouble with relationships". He was sent to counselling. The Counsellor gave him the unproven (actually research has disproved it) theory that his condition was because his father was distant with him when he was a small boy. Seizing this reason for being special and for demanding special treatment, the Narcissist (who had not been told the name of his diagnosis) said he would take his own treatment from there and stopped going!
There are many kinds as well, not all Narcissists are loud and boastful. Some, known as "Covert" can seem introverted and shy, but none the less will treat people secretly in the meanest and cruelest of ways - usually the victim is their wife/husband and often that person suffers terrible depression and a breakdown. In public they will put on an act and seem to be a pillar of the community or "that nice man/lady". There are millions of people in the world suffering, at home, work, school... because of the cruel and insidious ways narcissists work. If you google "bullying, controlling behaviour" you will get a lot of Narcissism information pop up.
Seeing the suffering and how hard it was for victims to get help was what made me devote my time to trying to understand this terrible problem and to help people not become victims. Victims are usually lovely, kind, generous, compliant, understanding people who never put themselves first. They get sucked in by a con-trick story, because these people are fantastic liars, and think they are helping the person. Then the narcissist turns on them and breaks them down, denigrating them, treating them like dirt, being incredibly selfish. There is a massive amount of information on the web, but not all exactly accurate. On YouTube, you could watch Dr Craig Malkin. I wouldn't just type in "Narcissism" because you will get a landslide containing the good and the very bad not to mention the ugly!
The book is "The Narcissism Epidemic: Living in the Age of Entitlement" by by Jean M Twenge, PhD and W. Keith Campbell, PhD first printed 2009. available from Amazon.
For info on research you could try googling it! Most research is on a medical or Psychiatry/psychology library though, needing membership.
Good luck and thanks for a very relevant question.