Recent advances in psychopathy research.

Can J Psychiatry. 2009;54(12):787-790. The study of psychopathy is a rapidly growing area of psychiatry and psychology. The articles in this In Reviewprovide insight into 3 critical domains of psychopathy research. Taken together, they illustrate the substantial progress made in understanding psychopathy and the mechanisms that underlie it. In addition, each identifies limitations of current knowledge and suggests important directions for fixture studies. Dr Robert D Hare and Dr Craig S Neumann1 provide a good introduction to the syndrome and summarize various issues related to using the expert-rater Psychopathy Checklist (PCL) measures to assess psychopathy, and address relations between psychopathy, antisocial behaviour, and violence. In reviewing similarities and differences between psychopathy and antisocial personality disorder (ASPD), they argue persuasively that psychopathy merits a greater role in diagnostic taxonomies. Their reviews of the application of multivariate statistical methods and intervention studies are especially informative. Regarding intervention, they make the provocative argument that treatment need not alter the personality of psychopathic offenders to reduce antisocial behaviour. They also review recent findings suggesting somewhat effective treatment both of adults and of youth with psychopathic features. I comment here on only a few of these issues. First, Dr Hare and Dr Neumann' address the trend toward studying the dimensions underlying psychopathy rather than psychopathy itself. These studies raise questions about when the full psychopathy syndrome, compared with one of its components, is most useful in predicting outcomes of interest. Although they illustrate this issue within the domain of antisocial behaviour, the same issue applies to the affective, cognitive, and physiological anomalies associated with psychopathy. A related issue is that regression and structural equation modelling studies commonly report unique relations of factor scores to scores on criterion variables. However, because intercorrelations between psychopathy factor scores often account for one-half or more of the variance in a factor score, it is difficult to interpret the meaning of relations that are evident only after controlling for the influence of other factor scores.2 Substantial additional research on this issue is needed. Second, they review recent research suggesting the possibility of rater bias in assessments completed by clinicians in adversarial contexts. Given the increasing use of psychopathy in courtrooms, it is striking that so much of what we know about the disorder is based on research in which psychopathy is assessed confidentially. Evidence on the impact of biased self-presentation3 and on rater bias in adversarial contexts suggests that PCL ratings may be less reliable in forensic than in laboratory settings,4'5 another critical direction for fixture research. As Dr Hare and Dr Neumann note,1 PCL assessments that are completed based solely on file material provide a method that circumvents the need to interview defendants. However, such assessments may provide less information at higher levels of psychopathy and less adequate assessments of interpersonal-affective aspects of psychopathy.6 Whereas Dr Hare and Dr Neumann note that PCL: Youth Version (YV) scores have many of the same correlates as PCL - Revised scores, their chief focus is on psychopathy in adults. In contrast, Dr Paul J Frick7 reviews the burgeoning literature on youth with psychopathic traits. Given the probability that understanding the development of psychopathy will aid in preventing it, the past decade has seen a dramatic increase in studies of youth with psychopathic traits. Dr Frick's work occupies a pivotal place in this growing empirical literature. Instead of using expert-rater measures, Dr Frick7 focuses on studies employing parent, teacher, or self-ratings of psychopathic traits. …