M. J. Vitacco

Cooke et al (2007) claim that there is no compelling empirical evidence to support the conclusion that antisocial behaviour is a central feature of psychopathy. However, in the same issue of the Journal Viding et al (2007) report a common genetic component to callous–unemotional traits and antisocial tendencies. Other studies cited by Viding et al report similar results. Moreover, Larsson et al (2007) reported that the same general four factors present in our four-factor model of psychopathy (Vitacco et al, 2005) all loaded onto a single genetic factor. Longitudinal research (not cited by Cooke et al) indicates that antisocial tendencies are significantly linked to the longitudinal stability of psychopathic traits (Frick et al, 2003). Cooke et al refer to the work of Cleckley (1988) to support their position, but in Cleckley’s accounts of psychopathy antisocial behaviours play an important role. As Patrick (2006: p. 608) noted, ‘ There is no question that Cleckley considered persistent antisocial deviance to be characteristic of psychopaths. Without exception, all the individuals represented in his case histories engage in repeated violations of the law – including truancy, vandalism, theft, fraud, forgery, fire-setting, drunkenness and disorderly conduct, assault, reckless driving, drug offences, prostitution, and escape.’ As Blackburn (2007: p. 145) recently put it, ‘ Contra Cooke,... antisocial behavior, conceived broadly, is a characteristic feature of psychopathy.’

In our paper based on a very large sample (Vitacco et al, 2005), we demonstrated the conceptual errors and flaws in modelling that went into the development of Cooke’s model and provided evidence for the four-factor model. Interestingly, Cooke et al did not cite this large study but rather chose to cite our small preliminary studies, although they are in line with our larger study. We do not view criminality as central to psychopathy. Indeed, the Psychopathy Checklist – Screening Version (PCL–SV) contains two items that refer to antisocial behaviour and that can be scored without evidence of criminality. The PCL–R and PCL–SV are virtually identical psychometrically, as noted previously by Cooke et al (1999).