Abstract
The neural bases of narcissistic and antisocial traits remain under debate. A key question is whether these traits are encoded within the triple network-comprising the default mode (DMN), salience (SN), and fronto-parietal (FPN) networks-and whether they impact these networks similarly. We conducted connectome-based analyses on resting-state fMRI data from 183 participants, examining graph-theoretical metrics in the DMN, SN, and FPN, using the visual and sensorimotor networks as controls. Predictive models of narcissistic and antisocial traits were developed using stepwise multiple regression and Random Forest regression to ensure generalizability. Seed-based analyses were conducted using regions identified by these models. Our findings revealed clear involvement of the triple network in both traits, supporting a shared neural substrate. Both traits were negatively predicted by the anterior cingulate cortex of the SN, reflecting reduced danger awareness and increased risky behaviors. Conversely, both were positively predicted by the lateral prefrontal cortex of the FPN, suggesting augmented strategic thinking to manipulate others and increased planning skills to achieve personal goals. Besides similarities, there were differences. Specific hubs of the DMN were positively associated with narcissism but negatively with antisocial traits, possibly explaining their differences in self-reflection and thinking about the self, largely present in the former, but usually reduced in the latter. These results expand on prior evidence linking the triple network to personality traits and suggest both shared and distinct neural mechanisms for narcissism and antisociality. These findings may help inform the development of biomarkers for personality pathology and guide biologically informed interventions.