Saddam Hussein. Henry VIII. Adolf Hitler. Just the mention of these names recalls the violent acts and intimidation that defined what some might call their psychopathic reigns. But what if we told you that scholars have also attributed psychopathic qualities to Teddy Roosevelt, Winston Churchill and John F. Kennedy? [source: Dutton] No, these oft-venerated leaders weren't murderous dictators. But the fact that they share some of the same qualities as their despicable counterparts tells us that psychopathic personality, or psychopathy, is largely misunderstood by the general public.
Psychopathy is a spectrum disorder, meaning people can display some psychopathic qualities without actually being a full-on psychopath. Only those who reach a certain threshold of such qualities are considered psychopathic. Individuals with extreme cases tend to display a very specific set of characteristics, namely a lack of conscience or empathy. But these hideous tendencies often go unnoticed because the same people can also be very charming. It's this strange combination of traits that make psychopaths difficult to pin down and sometimes — but not always — incredibly dangerous [source: Psychology Today].
Startlingly common, psychopathy cuts across historical and cultural boundaries. The first person to describe such individuals was Aristotle's student Theophrastus, a fourth-century B.C.E. philosopher who labeled them "the unscrupulous." Literature provides additional evidence for its past role in human existence. From Greek and Roman mythology and Chinese epics to Biblical stories and Shakespeare, cold, callous characters like Medea, Cain and Richard III can practically be diagnosed through the pages of a book. Preindustrial societies such as the Yorubas of southwestern Nigeria even have their own word for psychopaths: "aranakan." They describe an aranakan as "a person who always goes his own way regardless of others, who is uncooperative, full of malice and bullheaded" [source: Kiehl and Hoffman].
Today, scientists estimate that psychopaths make up as much as 1 percent of the general population [source: Choi]. That means there could be more than 3 million in the United States alone, and a shocking 70 million worldwide. So why hasn't global society descended into a "Lord of the Flies" hellscape? As it turns out, psychopathy is a bewilderingly complex disorder — which is what makes it so interesting.