Delineating the construct of psychopathy : psychometric evidence of alternative measures

Abstract

Psychopathy is a complex construct with various definitions featuring both personality traits, such as egocentricity, lack of empathy and guilt, dishonesty, callousness, and interpersonal dominance, as well as maladaptive behavior patterns. PCL-R is currently the most commonly used method of assessment. However, how psychopathy should best be defined and measured is debated. The overall aim of this thesis was to contribute to enhanced methods of assessment of psychopathic personality as well as add to the knowledge of the construct of psychopathy. For study I, we conducted a survey study with prison staff (n = 87) exploring their attitudes towards psychopathy. Study II, III and IV is based on a cross-sectional study of offenders serving a prison sentence at any of the high security facilities in Sweden (n = 201).

The CAPP is a conceptual model aiming to be a comprehensive and comprehensible presentation of psychopathy in a clinical context. The aim of Study I was to investigate if correctional staff perceived the symptoms of the CAPP to be indicative of psychopathy in men and women. The results gave support for the CAPP conceptualization, demonstrating few differences in what is perceived as typical comparing men and women with psychopathy. Study II focused on investigating the psychometric properties of the TriPM, which is a self-rating instrument based on the triarchic model of psychopathy. We found that the convergence of the TriPM and the PCL-R was generally satisfying. Furthermore, the associations validity evidence was generally in accordance with expectations. However, we also saw some problems in the measurement, particularly regarding the subscales of Meanness and Disinhibition, that did not seem to be adequately differentiated. In study III we investigated if ADHD symptoms and cognitive functioning were related to specific subcomponents of psychopathy. We found that self-rated ADHD symptoms and psychopathy was highly associated, both regarding the PCL-R and the TriPM, but that cognitive functioning was not associated with psychopathy. The results highlight that there is a considerable symptom overlap in the measurements of ADHD and psychopathy. Study IV aimed to investigate the risk pathway of COMT genotypes to ADHD and antisocial behavior. We did not find any support for COMT genotype as a risk factor for ADHD or psychopathy in our sample. However, this might be attributable to the fact that the effects of individual genotypes are too small to be detectable in small sample studies.

The main conclusion of this thesis is that the inclusion of items of impulsive and antisocial behavior in measures of psychopathy may contribute to making them too unspecific. That might result in difficulties distinguishing psychopathic traits from ADHD in offenders and points to the need of thorough consideration of all available information in clinical assessments of ADHD to avoid over-diagnosing.