26 May 2021: Computational phenotyping in Borderline Personality Disorder using a Social Hierarchy Probe

Iris Vilares
Department of Psychology
University of Minnesota

Dysfunction in social interactions is a hallmark feature of several psychiatric disorders. However, due to their complexity, social interactions are also extremely hard to study. Experimental economic games have been successfully used to quantitatively analyze behaviors and motives relevant to social interactions, and the emerging field of computational psychiatry has been applying these techniques to understand apparent aberrant social decision-making in people with psychiatric disorders.

One important aspect of social interactions that has scantly been studied with experimental economic games is how much people value being in a more dominant social hierarchy position. A mal-adaptive reaction to social dominance may present a significant source of vulnerability for neuropsychiatric disorders, and can be particularly relevant for personality disorders that have trouble sustaining social relations, such as borderline personality disorder (BorPD).

Here, we were interested in knowing how people with BorPD value and behave in social interactions when there are differences in social dominance, and how (or if) these differ from controls. Moreover, we were interested in finding computational phenotypes of these behaviors. For this, we had participants (169 controls and 312 BorPD patients) play a multi-round Social Hierarchy game where money could be used to increase (or maintain) social status and applied computational models to the obtained behavior.

We found no difference between BorPD patients and Controls in the amount of money spent to become (or remain) in the dominant position, the challenge rate, or the number of rounds in the dominant position. However, we found that BorPDs in the dominant position transferred more money to the other player when first alpha. In addition, they finished the game with a more equitable distribution of points between them and the game partner. The computational model revealed promising computational phenotypes and suggests that BorPD patients may have a higher disutility from losing their status, and this was associated with higher self-reported feelings of shame and aggression tendencies. Overall, our results indicate that BorPDs and Controls value social dominance similarly but that they may be particularly sensitive to losing status once they have it. In addition, our results suggest BorPDs, when in control, may be especially prosocial, and offer specific computational parameters that can be used to quantitatively characterize and phenotype each individual.

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