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The PCL-R is a 20-item symptom construct rating scale used predominantly in forensic settings. Each of the 20 items is a complex, higher-order trait (i.e. Shallow Affect, Criminal Versatility; Impulsivity). The response format is a 3-point scale, where 0 = item does not apply; 1 = item applies somewhat; 2 = applies definitely. Once completed, a suitably qualified clinician will sum individual items to yield dimensional scores that reflect the severity of psychopathic traits. A score of 30 or greater corresponds to a diagnosis of psychopathy. To put scores into context, an individual with no criminal background will generally score at around 5, and many non-psychopathic criminals score around the 22 range. The administration and scoring will take about 3 hours. An important note is that the PCL-R is not used in isolation to perform a diagnosis; rather, it is used in combination with a semi-structured interview and a review of the client’s file records and history. This is to compensate for the face that psychopaths are prone to lying, and are generally quite good at it. The interview evaluates the background of the subject, such as their work and educational background, marital and family status, and criminal background. Overall, two key elements of a psychopath are assessed: selfish and unfeeling victimisation of other people, and an unstable and antisocial lifestyle.
The norms for the PCL-R are based on data of 7 samples of adult male prisoners (N = 1192) and 4 samples of adult male forensic psychiatric prisoners (N = 440). In terms of its construction, more than 100 items were generated through a literature review and clinical experience. Thereafter, factor analysis reduced the 100 items down to 20 reliable items. The PCL-R has good reliability and validity (internal consistency = .87; interrater reliability =.94; test-retest reliability = .89 (Hare, Clark, Grann & Thornton, 2000). Additionally, the predictive validity of the PCL-R is good insofar as results from several studies have indicated that the PCL-R scores are correlated with antisocial and violent behaviour (inside and outside of prison). This includes recidivism and response to correctional treatments (Grenn et al., 1993). In comparison to other measures of psychopathy, the PCL-R’s ability to predict criminal behaviour is as good as, or better than the ADP and MMPI (Hare, 1993).
The PCL-R is available to buy online at a cost of about $550 US. It is a useful diagnostic tool in forensic populations and is also used in research. In considering the populations that the PCL-R is used with, research in this area would be difficult in terms of approval of ethics. It is imperative that this tool is only used by professionals who have been specifically trained in its use and who have a comprehensive understanding of the current literature pertaining to psychopathy (Freeman, 2001). Diagnosing an individual as a psychopath is a very serious statement with everlasting implications for the person and their family. Notwithstanding, when used by competent professionals, the PCL-R is a reliable and valid tool for diagnosing psychopathy in forensic settings.
Grann, M., N. Langström, A. Tengström and G. Kullgren. Psychopathy (PCL-R) predicts violent recidivism among criminal offenders with personality disorders in Sweden. Law and Human Behaviour, 23, no. 2 (April, 1999): 205-217.
Hare, Robert D. (1993). Without Conscience: The Disturbing World of the Psychopaths Among Us. New York, NY: The Guilford Press.