That is quite a question!
What is the difference between an NPD and a person just acting like an *sshole?
...Especially if they do it often, like for years...like for more than sixty years.
The ones I am thinking of took major blows as children, and continued taking both the short end of the stick, and direct hits financially and emotionally in adulthood.
They reacted very strongly, taking extreme stands, trying to overwhelm their tormenters, as well as everyone else. They hit when they thought they were entitled, 'supposed to' (as parental 'discipline' and chastizing), even chastizing spouses and parents and sometimes friends, though they usually limited their disapproval to loud pronouncements, telling off, and dramatic final separations...never to see or speak again.
One killed himself...looking to 'square' with his estranged mother at the end, but unable to locate her after all.
As far as I can see, over-discipline led to the downfall of all three, a father and his two sons...perhaps unto one of the two grandsons also.
The father went on to raise a second family, and devastated those children as well.
Religious fervor played a significant role, right from the get-go, even to total rejection of religion in any form. These men were/are desperate for high respect/regard.
Perhaps it is to their credit that they did no one real physical harm, but they were/are unable to be completely happy themselves, and certainly hurt their families emotionally.
Narcissistic? Certainly, but probably not true narcissists. Just never learned NOT to think, feel, and act like *ssholes, I think.
Not psychotic...just wrong.