While the demographics of psychopathy may be little murky, the behaviors are pretty well established. The Hare Psychopathy Checklist, the most widely used diagnostic tool for the disorder, lists 20 characteristics: glibness and superficiality, grandiosity, need for stimulation, pathological lying, cunning and manipulativeness, lack of remorse or guilt, emotional shallowness, callousness and lack of empathy, parasitic lifestyle, poor behavioral controls, sexual promiscuity, early behavior problems, lack of realistic long-term goals, impulsivity, irresponsibility, failure to accept responsibility, multiple marriages, juvenile delinquency, revocation of conditional release (like parole violations), and committing a variety of crimes [source: Kiehl and Hoffman].
While someone afflicted with these horrifying traits might seem easy to pick out, psychopaths are actually quite good at hiding them. Still, there are some giveaways. Part of what makes them so hard to pin down is their charm. They're great conversationalists and are generally quite likeable. But things can turn dark when their lack of conscience and empathy shows through; psychopaths will often do harmful things to others and refuse to accept responsibility. Instead, they'll blame others and continue do whatever it takes to achieve their objective. Another giveaway is their ability to use people's emotions against them, using guilt trips, flattery and sympathy to get what they want. As if all that isn't bad enough, psychopaths don't think rules apply to them. They think they can get away with anything because they're smarter and more important than anyone else [source: Morin].
Right now you may be thinking, "Wait, I know someone like that." And you might be right. Psychopaths aren't all serial killers or even criminals. Sure, they're overrepresented in the prison populations, making up some 25 percent of that group even though they're only 1 percent of the general population [source: Wynn et al.]. But with 3 million in the United States, there are plenty of psychopaths functioning as productive members of society. Some researchers even suggest that psychopathic traits help people succeed in some professions, like politics and finance. One study of the financial services industry, for example, suggests the profession's rate of psychopathy could be as high as 10 percent! That's not surprising, though, when you consider how characteristics like superficial charm, the ability to handle high-pressure situations, the desire for power and a willingness to take risks might be beneficial in these professions. It's no wonder Churchill and Kennedy might've had a touch of the disorder [sources: Silver, "Wall Street"; Silver, "Politicians"].
If you think you know a psychopath, resist the temptation to engage with his manipulations; that's what he wants you to do. Instead, accept that psychopaths are just damaged people whose actions are more meaningful than their words. They'll throw you under the bus if they need to, so guard your reputation, and if you have to, propose strategies in which you both win. In the end, though, it's best just to say away [source: Barker].