That’s widely understood by clinicians and psychologists, so nothing new. In the end it likely causes mental suffering to the people closely involved with narcissists like partners, children … - that’s what all types have in common as the outcome.
I would say that from the outside, it's really very clear that America has become more narcissistic over the last 35-40 years, but I think there's also evidence of a reckoning -- of a younger culture beginning to mix more self-effacement in with their self-expression.
I'd place the UK slightly lower on the scale of worsening narcissism, but I am sure other countries would observe it in us. Gen Z would seem to be getting tired of the whining over here, too.
