<p>The study aims to explore the associations between narcissism, interpersonal behaviors, and aggression using situational measurement. Using an experience-sampling approach, the study examined the effect of narcissism and its fine-grained components on daily affective experiences and aggressive behaviors in the context of social interactions. Data was collected from 478 undergraduate students that were instructed to complete four prompts a day for 10 days. Narcissism and negative affect predict higher aggression overall. Grandiose narcissism affects aggression directly, and vulnerable narcissism affects aggression solely through negative affect. Interpersonal antagonism presents as the core element in narcissism that drives its association with aggression. Results are robust across different domains of aggression. In real-life social interactions, narcissism dimensions differentially affect the way individuals experience social interpersonal and process negative affect, and thus in both research and clinical practices, narcissism is the most assessed as a heterogeneous, multidimensional construct.  </p>

Narcissism is a truly Janusian phenomenon, consisting of both narcissistic grandiosity, exhibitionism, admiration-seeking, boldness, and dominance on the one hand, and narcissistic vulnerability, introversion, withdrawal, hypersensitivity, and anxiety on the other hand. While there is broad consensus that these two seemingly contradictory faces of narcissism can be empirically discerned and have different implications for psychological functioning and mental health, there is not yet agreement on whether grandiose and vulnerable narcissism should be regarded as independent traits or as two manifestations of one personality trait. Previous research indicates that both views hold true when the level of grandiosity is considered a moderating factor: while grandiose and vulnerable narcissism are largely unrelated in the range of normal personality variation, they are correlated in the range of high grandiosity (Jauk et al., 2017b). Here, we replicate and extend this work in an independent sample (N = 891) using a more comprehensive narcissism inventory grounded in a new trifurcated model of narcissism. The trifurcated model partitions narcissism into three main personality dimensions: agentic extraversion, antagonism, and neuroticism. We found a significant breakpoint in the association between narcissistic grandiosity and vulnerability at 75% cumulative frequency of grandiosity. While grandiosity and vulnerability are unrelated below this breakpoint (r = 0.02), they are strongly correlated above (r = 0.45). In the lower range of grandiose narcissism, grandiosity draws more upon agentic extraversion and is largely associated with mental health. In the upper range, however, grandiosity is more strongly linked to antagonism and is substantially associated with fear, negative affect, and depression. These findings provide evidence for the view that grandiose and vulnerable narcissism are distinct traits at lower levels of grandiosity, but blend into an antagonistic core with signs of psychological maladjustment at higher levels. Implications for research on narcissism as a personality trait, as well as clinical practice, are discussed.