The New York Times > Health > Mental Health & Behavior > For the Worst of Us, the Diagnosis May Be 'Evil': "When you start talking about evil, psychiatrists don't know anything more about it than anyone else,' Dr. Simon said. 'Our opinions might carry more weight, under the patina or authority of the profession, but the point is, you can call someone evil and so can I. So what? What does it add?'"
Researchers have found that some people who commit violent crimes are much more likely than others to kill or maim again, and one way they measure this potential is with a structured examination called the psychopathy checklist.
As part of an extensive, in-depth interview, a trained examiner rates the offender on a 20-item personality test. The items include glibness and superficial charm, grandiose self-worth, pathological lying, proneness to boredom and emotional vacuity. The subjects earn zero points if the description is not applicable, two points if it is highly applicable, and one if it is somewhat or sometimes true.
The psychologist who devised the checklist, Dr. Robert Hare, a professor emeritus at the University of British Columbia in Vancouver, said that average total scores varied from below five in the general population to the low 20's in prison populations, to a range of 30 to 40 - highly psychopathic - in predatory killers. In a series of studies, criminologists have found that people who score in the high range are two to four times as likely as other prisoners to commit another crime when released. More than 90 percent of the men and a few women at the top of Dr. Stone's hierarchy qualify as psychopaths.