Now that we've established the history and vocabulary of psychopathy, let's dig a little deeper into the characteristics of the disorder.
A good place to start is with demographics. Do age, race or gender play a role in psychopathy? The answer is a little tricky because psychopaths, by their very nature, aren't likely to admit to having a problem. Without any self-reporting, researchers instead have to rely on survey data gathered largely from criminals who are compelled to undergo psychiatric examination. Conclusions based on such data are often uncertain at best or controversial at worst.
Studies related to age and race are particularly cloudy. One analysis on age, for example, showed that some psychopathic traits appear to decline as patients get older, though it's unclear why [source: Harpur and Hare]. Researchers also disagree about whether children can be considered psychopaths at all. While some studies suggest that infants and toddlers can express traits associated with psychopathy, children can't technically be diagnosed with the disorder, and such traits don't guarantee they'll become psychopaths as adults [sources: Harrold, McLain, Ossola].
More contentious are studies relating psychopathy to race. Such analyses — particularly those that have tried to link high rates of the disorder to African-American and Native-American communities — have been heavily criticized in the psychiatric community as racist and dismissive of socioeconomic factors [sources: Lynn, Zuckerman].
Gender, on the other hand, appears to have a pretty clear influence on psychopathic traits. Women consistently score lower on psychopathic evaluations, a finding that holds up even among violent criminals. One study of a prison population, for example, pinned the occurrence of psychopathy at 11 percent for women versus 31 percent for men [source: Wynne et al.]. Still, some researchers dispute this claim, suggesting instead that women simply express psychopathic traits in a way that overlaps with other conditions, like borderline personality disorder (BPD). According to this theory, women typically diagnosed with BPD — particularly those who swing between extreme emotional responses and callous, manipulative behavior — may just have a female version of psychopathy [sources: Johnston and Sprague et al.].