Christine Michie

Psychopathy across cultures : North America and Scotland compared

Differences in the prevalence and presentation of psychopathic personality disorder between North America and Scotland were evaluated. R. D. Hares (1991) Psychopathy Checklist--Revised ratings obtained from a sample of 2,067 North American male prisoners and forensic patients were compared with ratings obtained from 246 Scottish male prisoners. Item response theory methods were used to examine differences in the performance of items and to equate the scale across settings. The items had equal relevance to the description of psychopathic personality disorder in both settings; however, the Scottish prisoners had to have higher levels of the underlying latent trait before certain characteristics became apparent. The prevalence of the disorder appears to be lower in Scotland. Explanations for the observed differences in terms of enculturation, socialization, and migration are explored.

An Item Response Theory Analysis of the Hare Psychopathy Checklist-Revised

Hares Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991) is the measure of choice for measuring psychopathic personality disorder. An item response theory (00) approach was adopted to analyze both test and item functioning. Data from 2,067 North American participants were analyzed. The analysis confirmed that the test was appropriate for both the diagnosis of psychopathic personality disorder and for making measures of trait strength. 1\vo correlated but distinct factors underpin scores on the PCL-R: Factor I, Selfish, Callous, and Remorseless Use of Others, and Factor 2, Chronically Unstable and Antisocial Life style. Items related to Factor I are generally more discriminating and provide more information about the trait than items relating to Factor 2. Future uses of 00 procedures in the analysis of PCL R data are discussed.

Evaluating the Screening Version of the Hare Psychopathy Checklist—Revised (PCL:SV): An item response theory analysis.

The Screening Version of the Psychopathy Checklist-Revised (PCL:SV; S. D. Hart, D. N. Cox, & R. D. Hare, 1995) was developed to complement the Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991), and for use outside forensic settings. The PCL:SV takes less time to administer and requires less collateral information than the PCL-R. An item response theory approach was adopted to determine similarities in the structural properties of the 2 instruments and whether the PCL:SV could be regarded as a short form of the PCL-R. Eight of the 12 items in the PCL:SV were strongly parallel to their equivalent PCL-R items. Of the 4 items PCL:SV items which differed from their equivalent PCL-R items, all 4 were found to be equal or superior to their equivalent PCL-R items in terms of discrimination. The analyses confirmed previous results that the interpersonal and affective features of psychopathy have higher thresholds than do the impulsive and antisocial behavioral features; individuals have to be at a higher level of the psychopathic trait before the interpersonal and affective features become evident. The PCL:SV is an effective short form of the PCL-R.

Limitations of Diagnostic Precision and Predictive Utility in the Individual Case: A Challenge for Forensic Practice

Knowledge of group tendencies may not assist accurate predictions in the individual case. This has importance for forensic decision making and for the assessment tools routinely applied in forensic evaluations. In this article, we applied Monte Carlo methods to examine diagnostic agreement with different levels of inter-rater agreement given the distributional characteristics of PCL-R scores. Diagnostic agreement and score agreement were substantially less than expected. In addition, we examined the confidence intervals associated with individual predictions of violent recidivism. On the basis of empirical findings, statistical theory, and logic, we conclude that predictions of future offending cannot be achieved in the individual case with any degree of confidence. We discuss the problems identified in relation to the PCL-R in terms of the broader relevance to all instruments used in forensic decision making.

Explicating the Construct of Psychopathy: Development and Validation of a Conceptual Model, the Comprehensive Assessment of Psychopathic Personality (CAPP)

Psychopathic personality disorder (PPD) has important clinical and forensic implications. But much more effort has been devoted to assessing or diagnosing PPD than to explicating or defining it. In the first part of this paper, we describe the development of a conceptual model or “concept map” of PPD. Based on a systematic review of descriptions of PPD in the clinical and research literature, as well as consultation with subject matter experts, we identified key features of the disorder and translated them into 33 symptoms, presented as natural language (i.e., non-technical) trait descriptive adjectives or adjectival phrases. Each symptom in turn was defined by three synonymous adjectives or adjectival phrases. The 33 symptoms were grouped rationally to reflect six domains of personality functioning. In the second part of the paper, we discuss research completed and in progress intended to validate the CAPP conceptual model.

The Structure of Violent Behavior - A Hierarchical Model

Common difficulties in measures of violent behavior are their multidimensional nature, the nonempirical ordering of violent acts, the inclusion of undiscriminating items, and differential precision of measurement across the range of seriousness. Data collected on a sample of 250 male Scottish prisoners, using the MacArthur Community Violence Screening Instrument, are examined using confirmatory factor analysis and item response theory (IRT) analysis. A hierarchical model with a coherent superordinate factor overarching two lower order factors—violence based on weapon use and violence without weapon use—provide the best fit to the data. The ordering of the items on the scale does not conform to the order indicated by IRT analysis. Items vary considerably in the amount of information they provide, with the precision of measurement of the total scale being poor at high levels of the scale. Ways of improving the measurement of violence are discussed.

The Comprehensive Assessment of Psychopathic Personality (CAPP): content validation using prototypical analysis.

The Comprehensive Assessment of Psychopathic Personality (CAPP; Cooke, Hart, Logan, & Michie, 2004) is a new personality-based model and clinical assessment of psychopathy. This study was the first to examine the content validity of the English-language CAPP. Content validation is a crucial part of the development and refinement of any new instrument. Prototypical analysis was used to evaluate the representativeness of CAPP symptoms to the psychopathy construct in adults. Symptoms were rated by international mental health professionals (N = 132). Findings support good content validity of the CAPP, with most symptoms rated as highly representative of psychopathy. Domains relating to interpersonal style were particularly prototypical. Confirmatory factor analyses further suggested that CAPP domains are highly unidimensional. However, some CAPP symptoms may be weaker items in the model and further refinement is needed.

Cross-national differences in the assessment of psychopathy: do they reflect variations in raters' perceptions of symptoms?

Cross-national differences in the prevalence of psychopathy have been reported. This study examined whether rater effects could account for these differences. Psychopathy was assessed with the Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991). Videotapes of 6 Scottish prisoners and 6 Canadian prisoners were rated by 10 Scottish and 10 Canadian raters. No significant main or interaction effects involving the nationality of raters were detected at the level of full scores or factor scores. Using a generalizability theory approach, it was demonstrated that the interrater reliability of total scores was good, that is, the proportion of variance in test scores attributable to raters was small. The interrater reliability of factor scores was lower, typically falling in the fair range. Overall, the results suggest that the reported cross-national differences are more likely to be in the expression of the disorder rather than in the eye of the beholder.

Structural, item, and test generalizability of the psychopathy checklist-revised to offenders with intellectual disabilities

The Psychopathy Checklist—Revised (PCL-R) is the most widely used measure of psychopathy in forensic clinical practice, but the generalizability of the measure to offenders with intellectual disabilities (ID) has not been clearly established. This study examined the structural equivalence and scalar equivalence of the PCL-R in a sample of 185 male offenders with ID in forensic mental health settings, as compared with a sample of 1,212 male prisoners without ID. Three models of the PCL-R’s factor structure were evaluated with confirmatory factor analysis. The 3-factor hierarchical model of psychopathy was found to be a good fit to the ID PCL-R data, whereas neither the 4-factor model nor the traditional 2-factor model fitted. There were no cross-group differences in the factor structure, providing evidence of structural equivalence. However, item response theory analyses indicated metric differences in the ratings of psychopathy symptoms between the ID group and the comparison prisoner group. This finding has potential implications for the interpretation of PCL-R scores obtained with people with ID in forensic psychiatric settings.

PSYCHOPATHY IN IRAN: A CROSS-CULTURAL STUDY

Few cross-cultural studies have assessed psychopathy and none have included a sample from non-western countries. This study investigated the factor structure of the Psychopathy Checklist: Screening Version (PCL:SV) in an Iranian sample, and compared the results with a western sample. Three hundred fifty-one Iranian prisoners were compared with 405 participants of the standardization sample of the PCL:SV. Confirmatory factor analysis and item response theory method were used for data analysis. The Iranian data fitted well with the hierarchical three-factor model of psychopathy and neither two- nor four-factor models showed an adequate fit. Differential item functioning existed across samples, with discriminatory power of factor 1 (arrogant and deceitful interpersonal style) being lower in the Iranian sample that for factor 2 (deficient emotional experience) being greater in the Iranian sample than the standardization sample. Deficient emotional experience might be the most significant factor in diagnosing psychopathy, regardless of the studied culture. Other factors appear to be relatively culture-specific.