How do people with borderline personality disorder respond to norm violations? Impact of personality factors on economic decision-making.

Research suggests that patients with borderline personality disorder (BPD) experience profound difficulties in relationships. These difficulties reside, in part, in patients' tendency to overattribute negative emotions to self and others and in behaviors that are consistent with an opportunistic interpersonal orientation, as well as pathological identification mechanisms. Accordingly, the present study sought to examine the relationship between personality traits and behavior in BPD using an economic game designed to elicit participants' egocentric versus altruistic attitudes. Thirty patients with BPD performed a Dictator Game with the option to punish observed unfair behavior. Personality traits were measured using the NEO-FFI and the Mach-IV Scale. For comparison, 30 matched nonclinical subjects were recruited. BPD patients scored significantly higher on Neuroticism and Machiavellianism. Conversely, patients had lower scores on Agreeableness, Extraversion, and Conscientiousness than controls. While high Machiavellianism and low Agreeableness were associated with selfish behavior in the control group, the opposite was found in BPD. Inverse correlations of Extraversion and Openness with the degree of costly punishment were present only in the BPD group; moreover, Neuroticism correlated positively with the degree of punishment in BPD patients. The motivation for costly punishment differs between BPD patients and controls. The behavior observed in BPD can be interpreted as "angry retaliation" by means of identification with the victim's perspective, but does not seem to be altruistically motivated.