The most widely used measure of psychopathy is also the number one tool used to assess risk of future violence. In fact, forensic psychologists use the PCL-R to assess risk twice as often as they use tools that were specifically designed as risk assessment tools. This is not the case for other well-validated measures of psychopathy such as the Psychopathic Personality Inventory (PPI). Instead, the diagnostic measure for personality disorders has become the most widely used tool for assessing violence risk, owing to a series of studies indicating that the PCL measures robustly predict violence and recidivism for offenders, forensic patients, and even psychiatric patients. Although the absolute size of this relationship is weak (r ~ .25), the PCL-R is among the strongest single predictors of violence and other criminal behavior, on a level that competes with leading risk assessment tools.
Although this relationship suggests that emotionally detached psychopaths callously use violence to achieve control over and exploit others, recent research suggests otherwise. The lion’s share of the PCL-R’s utility in predicting violence is attributable to its saturation with indices of past violence and criminality. Although there is debate about its factor structure, the original PCL-R model has two moderately correlated scales: The first assesses core interpersonal and affective features of emotional detachment that are central to most conceptualizations of psychopathy; the second assesses impulsivity, irresponsibility, poor anger controls, and antisocial behavior, which some view as peripheral to psychopathy. A meta-analysis of 42 studies indicated that the PCL-R’s antisocial behavior scale is significantly more predictive of violent and general recidivism than its emotional detachment scale. Moreover, three original studies indicate that the emotional detachment scale does not significantly predict future violence, independent of its association with the antisocial behavior scale.