Self-other distinction in borderline personality disorder

Theoretical framework: Humans are prone to automatically mirror the actions of their counterparts and to reflect on their thoughts, beliefs, and emotions to better understand what another person is doing, thinking, or feeling. Yet, individuals also have the complementary ability to disentangle self- from other-related mental representations, termed self-other distinction (SOD). Impairments in SOD are prevalent in various psychopathologies, including borderline personality disorder (BPD). BPD patients often struggle to tease apart their actions, thoughts, and emotions from those of others, and this results in burdened interpersonal problems. According to our theoretical framework (De Meulemeester et al., 2021), the deficits in SOD are related to a lack of flexibility in switching between self- and other-related mental representations, resulting in either egocentric or altercentric biases. Which of the biases would dominate in a given context may depend on internal or external factors that need to be identified. Generally, more systematic research is needed to test our model’s predictions. Objectives: Our project aims to better understand the neuro-cognitive processes underpinning the SOD impairments in BPD; how attachment style and stress modulate them; and how findings from experimental settings translate to everyday life. In a series of studies, we will a) investigate SOD in BPD with wellvalidated SOD tasks in different domains, validate a novel questionnaire allowing efficient SOD assessment, and explore how differences in attachment style modulate SOD performance [WP1]; b) how acute stress influences SOD and in particular ego- vs. altercentric biases in BPD compared to HCs [WP2]; c) whether SOD impairments are associated with altered neural activations and how these altered neural activations maybe be related to SOD proficiency in everyday life [WP3]. Methods: WP1 is a multicenter experimental behavioral study combined with psychometric methods. WP2 induces stress using a well-established paradigm, the Trier Social Stress Test, and verifies its effects using a host of measures, including stress biomarkers (saliva cortisol). WP3 combines fMRI data collection during SOD experimental tasks with the following one-week experience sampling in everyday life. Level of originality: The combined evidence from the series of multi-method studies will be used to refine our theoretical model of SOD in BPD, and consequently to inform theories on SOD in the general population. A more comprehensive understanding of the key processes underpinning the deficits in SOD taps into the until now unsystematically researched avenue. Together, the applicants will be able to achieve what they would not be able to do separately: to perform methodologically sound and clinically relevant research on SOD impairments in BPD in the lab, daily life, and the scanner. Involved researchers: Luyten (KU Leuven), Bukowski (UCLouvain), Lamm (UniVienna), De Meulemeester, Pronizius