There is still a dearth of studies on the relationships between pathological narcissism and physical aggression (PA), particularly among psychiatric adult subjects. The present study aimed at assessing the relationships between PA, pathological narcissism, and clinician’s ratings and self-reports of DSM-5 Section II Narcissistic Personality Disorder (NPD).
Three-hundred and ten consecutively admitted Italian outpatient participants were administered the Italian translations of the Aggression Questionnaire (AQ), the Five Factor Narcissism Inventory (FFNI-SF), the Pathological Narcissism Inventory (PNI), the Personality Diagnostic Questionnaire (PDQ-4+) and the Structured Clinical Interview for DSM-5 Personality Disorders (SCID-5-PD), as part of their routine clinical assessment. Multiple regression analyses and hierarchical multiple regression analyses were performed in order to assess the relationships between physical aggression and pathological narcissism.
The PNI and FFNI-SF yielded significant and non-negligible bivariate associations with self-reports of PA. Pathological narcissism measures explained from 13.0% (PNI total score) to 24.0% (FFNI-SF-SF total score) in the AQ PA scale score. Notably, moderation analyses did not evidence any significant role of participant’s gender as moderator variables. Our multiple regression analysis findings showed that both grandiose and vulnerable features of pathological narcissism may be relevant for understanding self-reported PA among psychotherapy outpatients; however, this relationship was observed only when the FFNI-SF scale scores were used as predictors in multiple regression models. Rather, only the PNI vulnerable narcissism scale scores showed a significant association with the AQ PA score in multiple regression analyses. Hierarchical regression models documented that both PNI and FFNI-SF measures added a significant amount of information in predicting AQ PA scale scores to the information that was provided by both the PDQ-4+ NPD scale and the SCID-5-PD NPD scale.
As a whole, our findings suggest that both the PNI and the FFNI-SF should be used in assessing pathological narcissism features that may be relevant for understanding self-reported disposition towards physical aggression, at least in subjects who voluntarily asked for treatment.