Below is a link to a really good and informative article from Psychology Today about sociopaths and psychopaths,* and the devastation and misery they leave in their wake, both in personal or familial relationships, and on a much larger, societal level.
This article explains how to detect them. While only 4 percent of the population suffers from Antisocial Personality Disorder (sociopathy and psychopathy) , a larger portion (up to 15%) are situational sociopaths or psychopaths. This is explained in more depth in the article.
A malignant narcissist is a person with both Narcissistic Personality Disorder and Antisocial Personality Disorder. This combination of personality disorders is especially devastating because of the already conscienceless person’s insatiable need for adulation and approval. When narcissistic supply is abundant, instead of satiating the person and making them act more pleasant, as you might think, they become “drunk” on the ego “fuel.” This phenomenon is evident in Donald Trump, who, feeling victorious and vindicated after the Barr’s summary of the Mueller Report stated he did not collude with Russia to win the election, became “drunk on power” and his cruelty, gaslighting, lies, and unreasonable demands actually got worse.
*A small percentage of psychopaths (not sociopaths) choose to be prosocial instead of antisocial. Psychopathy, unlike sociopathy, is a condition a person is born with, in which the parts of the brain concerned with conscience are missing. Psychopaths can cognitively learn the difference between right and wrong, so they can choose to do the right thing (even if the motive for making that choice is always self serving). It’s not second nature to them but they may make that choice if they have learned it benefits them the most. In contrast, sociopathy is an acquired condition associated with malignant narcissism or antisocial personality disorder, and such a person will never choose prosocial behavior and in fact aren’t capable of doing so.