Unfortunately by the teens it's too late.
The personality is fully formed by then already.
I agree with op, there should be a system in place to stop these personalities developing in the first place. But it needs to be caught when children are very young. Which can be hard to spot. As things like selfishness and lack of empathy and manipulation ...Well to an extent, all kids do that.
But every time I hear of things like bullying in old folks homes or nurses kill people ect...and these institutions going 'we will learn from our mistakes to make sure these things things happen again' I think, how? You're going to keep hiring rotten peoples because, they exist, and nothing is being done to stop them coming into existence.
Also, there don't seem to be any checks and balances. Imo, organisations hiring people to work with the vulnerable (schools, hospitals, nursing homes) should have to do mandatory psychiatric evals on their students. 2 qualified psychaitrisrs should have to go on record stating there is no diagnosable cluster b personality.
I'd even go as far as to say universities should have to run these tests before admitting students to courses that may lead these students to 'caring' roles.
It would be good if ANY management role in every company required the same too. In order to help prevent workplace bullies getting extra footholds. But tbf some psychopaths make
..effective leaders (...and popular politicians xD).
But the fact is, we know that so many things like spousal abuse, workplace bullying, many violent crimes, frauds and power exploitation- come from these sorts of people. We know many of these disorders form in childhood. But nothing is being done comprehensively to tackle that.
So all these horrible things will keep happening en mass. Indefinitely.