Neural Protective Factors for Psychopathy: Differential Effects of Striatal Subregions

Background. Brain imaging research on psychopathy and other clinical conditions has largely focused on identifying risk factors, with virtually no research on neural protective influences. Increased striatal volume has been identified as a risk factor for adult psychopathy, but possible protective influences have not been considered. We addressed this gap by using a trichotomization analytic framework in two independent samples to examine both protective and risk effects of striatal subregional volumes on psychopathic personality. Methods. Study 1 consisted of 119 male and female participants and Study 2 consisted of 87 male and female participants, all recruited from temporary employment agencies. In both studies participants were administered a structural MRI to evaluate striatal subregional volumes and psychopathy was assessed using the Psychopathy Checklist—Revised. Results. Study 1 established that low volume of the caudate acted as a putative protective factor for psychopathy. Study 2, which allowed for the differentiation of the caudate into the head and body, showed that putative protective effects for the caudate were found for the body of the caudate but not the head. No evidence was found for high caudate volume acting as a risk factor. Conclusions. Findings highlight the importance of differentiating protective versus risk factors in neurobiological research on psychopathy. It is recommended that future brain imaging research on clinical disorders conduct follow-up analyses based on the trichotomization approach to further probe whether a functional or structural abnormality represents either a protective factor or a risk factor.