Trump's pathology -- "Narcissistic personality disorder" or in the extreme "malignant narcissism" -- occurs within 10% of the population. In Hollywood, there would be a disproportionate percentage. They can find their way into upper-tier management positions or even teaching. I know this firsthand. I have been "recovering" for about 10 or 15 years . . .
While we live in a culture of narcissism and a larger percentage of the population exhibit various narcissistic traits, the extremes are insidious. Fritz Lang, the German filmmaker, had produced a silent movie during the late 1920s featuring Peter Lorre as a serial child-killer: "Der Kinder Mord" or "M". The narcissist aspects of sociopathy often manifest themselves in the subject's inclination to tease his police-pursuers by leaving clues. It becomes an "I'm-smarter-than-you-are" sort of game.
He can then look back on his crimes with greater satisfaction, savoring his risk-taking successes. For this, he may also take trophies.
Trump does much the same thing. He blurts out in public exhortations with a treasonous implication, like "Russia -- if your listening! . . . "You can think of dozens more examples for the Putin-President and his "Henker" -- henchmen. Likes attract likes, so it is understandable that Hitler's entourage all exhibited similar narcissistic traits.
CIA would immediately refuse a disordered applicant under testing. Narcissists are often tempted to spill the beans -- about themselves, about their work, about things that are matters of secrecy or national security.
It would stand to reason that bullying behavior would accompany this other aspect. The narcissist on the outside may appear confident. On the inside, there's a deficit of self-esteem. Thus it is with bullies.
I submit this question of my own, having heard something from the television from a Trump biographer. Is it true, that at a pre-adolescent age, he had grabbed a smaller child by the ankle and hung him outside a second-story window to savor the child's screams?
There is a sadistic dimension in the lust for revenge.