). Unexpectedly, neither borderline nor narcissistic PD traits showed unique relationships with either aggression types, which appears to disconfirm our primary hypothesis that these PD traits mainly relate to reactive aggression. In contrast, several previous studies did find a relation between these PDs and proactive aggression (see Table 1 for overview). One possible explanation for the lack of unique aggression type findings in our research could be that all studies showing a relationship between subclinical narcissistic traits and aggression assessed traits with self-report questionnaires such as the Narcissistic Personality Inventory