From bench to bedside: Examining the interpersonal and affective context of borderline personality disorder as it unfolds over time in psychotherapy.

Wright et al. (2022) argued that the core of personality disorder (PD) is interpersonal in nature; thus, reconceptualizing PD as interpersonal disorders allows more focused assessment, formulation, and treatment planning. Previous research has examined the interpersonal and affective processes relevant to borderline PD (BPD), yet no study to date has investigated how these dynamics may shift in response to psychodynamic psychotherapy. We present preliminary data examining the interpersonal and affective context of BPD over time in an evidence-based treatment. Forty-five patients diagnosed with BPD who participated in a clinical trial of 18 months of transference-focused psychotherapy completed ecological momentary assessment rating interpersonal events in daily life for 14 days for up to three timepoints (0, 9, and 18 months). Multilevel models examined ratings of self and other interpersonal dominance/warmth and affect valence/arousal in the interpersonal field. Patients rated on average 35 events per timepoint, with over 3,300 events total. Results suggest reduced volatility in affective dimensions and in identity confusion, and changes in patients experiencing themselves and others as more friendly, happy, and energized over time in treatment. Shifts in patterns among interpersonal variables over the course of treatment suggest that patients developed a warmer experience of agency and affect. These changes align with the putative mechanism of transference-focused psychotherapy-to shift the habitual, maladaptive ways that patients perceive themselves affectively relating to others. Our assessment of other's affect extends research on the interpersonal situation. We conclude with recommendations for future research integrating advances in ecological momentary assessment reporting with clinical practice. (PsycInfo Database Record (c) 2025 APA, all rights reserved).