Emotions at the border: Increased punishment behaviour during fair interpersonal exchanges in Borderline Personality Disorder

This study evaluated whether the impairment in cooperation that characterizes individuals with Borderline Personality Disorder (BPD) can be explained by the difficulty to use emotion regulation strategies and to accurately perceive the fairness of others’ behaviour. Forty-one patients with BPD and forty-one sex and age matched healthy controls (HC) played the responder’s role in a Modified Ultimatum Game during which they were asked to apply three different emotion regulation strategies: Look, Distancing and Reappraisal. Offer rejection rates were used as an index of punishment behaviour. After the experiment, participants also rated the degree of perceived equity of the offers after receiving fair and unfair offers. Reappraisal was effective in decreasing punishment behaviours for unfair offers in both the BPD and HC groups. By contrast, BPD patients displayed a different behaviour than HC when making decisions upon fair offers, independently from the regulation strategies adopted. In fact, they rejected higher rates of fair offers than HC. Further, BPD patients judged fair offers as less fair than HC. This indicates an altered judgment and decision making on fair interpersonal exchanges. In conclusion, BPD patients exhibit increased punishment behaviour during fair, “favourable” social exchanges, which they tend to perceive as less fair than controls. Thus, BPD patients may be biased toward under-estimating positive feedback from others.