Expressions of antisocial behaviour have a detrimental impact on society. Given the heterogeneity among offenders, however, treatment effects yield various levels of success in diminishing...Show moreExpressions of antisocial behaviour have a detrimental impact on society. Given the heterogeneity among offenders, however, treatment effects yield various levels of success in diminishing antisocial behaviour. Knowledge on the origin of the differences between offenders is thus crucial. Recent research found that positive self-concept was associated with less hostility. This suggests that self-concept might explain some of the heterogeneity between offenders. The main objective of the present study was to examine the effect of the valence of self-concept on aggression type in individuals who presented high psychopathic traits. First, the association between psychopathy and aggression type was explored. Second, the relation between psychopathic traits and self-concept and the moderating effect of selfconcept on psychopathic traits and aggression was examined. Additionally, the relation between psychopathic trait factors (interpersonal-affective factor, and behavioural-lifestyle factor) and aggression types (proactive, and reactive) was examined, followed by an analysis to examine if selfconcept would differently moderate this relation. In total, 67 participants were included for this crosssectional survey study, of which 33 had completed a fMRI self-concept task. The questionnaires that were analyzed were the Youth Psychopathic traits Inventory and the Reactive-Proactive Aggression Questionnaire. The results indicated that a significant effect was found between both the interpersonalaffective factor (p = .001) and the behavioural-lifestyle factor (p = .019) and proactive aggression, and the behavioural-lifestyle factor and reactive aggression (p = .008). Second, a significant positive association was found between the interpersonal-affective factor and self-concept (p = .002). The moderation analyses showed that self-concept did not influence the relation between psychopathic traits and aggression. Given the positive correlation between the interpersonal-affective factor and proactive aggression and the association between self-concept and the interpersonal-affective factor, it can be argued that the promotion of a positive self-concept might lower the interpersonal-affective factor of psychopathy and therefore may also be of influence on aggression. This suggestion, however, needs a stronger body of empirical evidence to support it, since the moderation analysis did not support this hypothesis. Knowledge on the interaction between these variables could provide information for the design of possible treatment interventions for individuals with high psychopathic traits.Show less