Are Psychopathy Checklist (PCL) psychopaths dangerous, untreatable, and without conscience? A systematic review of the empirical evidence.

The Hare Psychopathy Checklist (PCL; Hare, Neumann, & Mokros 2018) scales are among the most widely used forensic assessment tools. Their perceived utility rests partly on their ability to assess stable personality traits indicative of a lack of conscience, which then facilitates behavioral predictions useful in forensic decisions. In this systematic review, we evaluate the empirical evidence behind 3 fundamental justifications for using the PCL scales in forensics, namely, that they are empirically predictive of (1) criminal behavior, (2) treatment outcomes, and (3) a lack of conscience. We found the PCL scales can predict criminal behavior to a statistically significant degree, though with important limitations. We found no evidence of PCL psychopathy being predictive of treatment and rehabilitation outcomes. We found no evidence of PCL psychopathy being predictive of a lack of conscience. These findings disprove widespread beliefs about PCL psychopathy among forensic practitioners and questions the current and future role of the PCL scales in forensic settings.