I'm sure you've all seen the article decrying that one in five of American citizens has a mental disorder. Of course when you read the article, it turns out the definition of "mental disorder" is pretty darn broad, to the point you wonder how anyone escapes the stigma.
Now here's a study that gets a bit more narrowly focused, specifically on sociopathy.
…Four percent of the global population is made up of sociopaths, Dr. Martha Stout, psychologist and clinical instructor in psychiatry at Harvard Medical School, tells us in her book "The Sociopath Next Door." That means one out of every 25 human beings has no conscience, no sense of right or wrong, no empathy, no ability to understand emotion – no soul. Worse, while they can mimic emotion, they see other humans as mere pawns or saps, to be used for their benefit or amusement, or both. Add that to the fact that science now is questioning whether there is any difference at all between sociopaths and psychopaths, and that those with narcissistic personality disorder also have some of the same characteristics (an inability to care about anyone but themselves), it means that "evil" is all around us, even at work…There's a support group for people like this. To join, look in the phone book under "Government"
H/T RKBA DUF Daily mailing.