The concept of psychopathy should be distinguished from the DSM-IV concept of antisocial personality disorder. While diagnosis of antisocial personality disorder is heavily dependent on a record of criminal behavior, psychopathy is more geared to the actual personality traits associated with criminal behavior. Such traits include callousness, superficial and shallow emotion, lack of empathy, irresponsibility, lack of remorse or guilt about harming others, and the tendency to exploit, manipulate and engage in predatory behavior toward others.

Psychopathic prisoners commit more serious and violent crimes than non-psychopathic prisoners. They are also more likely to recidivate (commit another crime) after they are released from prison. Moreover, psychopaths are more likely to commit premeditated rather than impulsive crimes. In Michael Woodworth and Stephen Porter’s 2002 study of 125 prisoners convicted of homicide, the thirty-four psychopathic prisoners were much more likely than the ninety-one non-psychopathic prisoners to have committed premeditated murders (93.3 percent vs. 48.4 percent).