Psychopathy is a serious personality disorder of which impulsivity is a key component. However, impulsivity is a multidimensional construct, with multiple approaches to measurement, and different measures may be differentially implicated in psychopathy. This study investigated the relationship between psychopathy as assessed by the Psychopathic Personality Inventory-Revised (PPI-R; Lilienfeld & Widows, 2005), a personality measure of impulsivity (Barratt Impulsiveness Scale-11), and four behavioural measures of impulsivity (GoStop Impulsivity Paradigm, Two Choice Impulsivity Paradigm, Delay Discounting Task, Iowa Gambling Task). A nonclinical sample (N = 80) was recruited from the local community to advance understanding of psychopathy in non-incarcerated samples. The results indicated that the personality measure of impulsivity was strongly correlated with the PPI-R, while the behavioural measures were either not correlated or only weakly correlated with the PPI-R. The results are discussed in terms of the multifaceted nature of impulsivity and the need for the further development of behavioural measures of impulsivity, given their importance in clinical assessment and intervention.
Psychopathy is a personality disorder characterised by a constellation of behavioural, affective and interpersonal traits (Cleckley, 1976 and Hare, 1991). It has been described as one of the most important constructs in clinical and forensic psychology (e.g., Snowden & Gray, 2011). The majority of research on psychopathy has been conducted in incarcerated or institutionalised samples. Nevertheless, it has been suggested that there are also “successful” individuals with psychopathy who possess the core personality features of psychopathy yet manage to avoid criminality and function well in the community (Benning et al., 2003 and Cleckley, 1976). One of the main factors hindering research in the area of subclinical/community psychopathy has been the lack of valid tools for examining psychopathy in the general population (Benning et al., 2003).
The most widely used and validated measure of psychopathy is the Psychopathy Checklist-Revised (PCL-R; Hare, 1991). However, the PCL-R was specifically designed for use in offender populations and requires extensive time and collateral information to complete, which is often not available in community settings. These issues have led to the development of self-report measures of psychopathy that are specifically designed for use in community samples. The Psychopathic Personality Inventory-Revised [PPI-R; Lilienfeld & Widows, 2005] is one of the most prominent of these instruments and was used in this study. The PPI-R provides an overall global psychopathy score and also scores on subscales of Fearless Dominance, Self-Centred Impulsivity, and Coldheartedness (see Copestake, Gray, & Snowden, 2011 for information on the relationship of these scales to the PCL-R). Previous work has suggested the importance of examination of the impulsivity at this factor level (e.g., Hart and Dempster, 1997, Sellbom and Verona, 2007 and Snowden and Gray, 2011).
Research on impulsivity has emphasised the complexity of the construct. Impulsivity has been variously defined, and definitions include an insensitivity to delayed rewards, the inability to delay gratification, and an inability to inhibit behaviour when inhibition is necessary (e.g., Ainslie, 1975, Cherek et al., 1997, Gerbing et al., 1987 and Schachar and Logan, 1990). Recent research has emphasised the multidimensional nature of impulsivity and has suggested that there are “varieties of impulsivity” (Evenden, 1999; p. 348). Impulsivity measures are often based on vastly different methodological and theoretical approaches and multiple measures are rarely administered in single investigations in order to reflect the multidimensional nature of impulsivity (Dougherty et al., 2005, Lane et al., 2003 and Reynolds et al., 2006). As such it is unclear whether the different measures relate to each other, and whether they reflect similar kinds of impairment in disorders in which impulsivity is implicated.
Prominent impulsivity measurement approaches include personality measures (i.e. self-report/psychometric measures) and laboratory behavioural measures. Self-report measures are cheap and easy to administer yet they are limited by the honesty, recall accuracy and insight from the respondents (Dougherty et al., 2005). This may be particularly problematic in a psychopathic sample (Lilienfeld & Fowler, 2006). Behavioural measures are important in the assessment of clinical disorders such as psychopathy given their more objective and state dependent quality, yet more research is required to better understand and validate these measures in a range of populations (Dougherty et al., 2003a and Dougherty et al., 2005).
1.1. The present study
The aim of the present study was to examine what aspects of impulsivity are related to psychopathy. Impulsivity was measured using a well-established self-report questionnaire (the Barratt Impulsiveness Scale [BIS-11; Patton, Stanford, & Barratt, 1995] and four behavioural measures that aim to measure different conceptualisations of impulsivity, (the GoStop Impulsivity Paradigm [GoStop; Dougherty, Mathias, & Marsh, 2003c], the Two Choice Impulsivity Paradigm [TCIP; Dougherty, Marsh, & Mathias, 2003b], Delay Discounting Task [DD; Bickel, Odum, & Madden, 1999] and Iowa Gambling Task [IGT; Bechara, Damasio, Damasio, & Anderson, 1994]). We measured psychopathy using the PPI-R.
