Personality functioning severity tracks mentalizing and memory problems in BPD

People with borderline personality disorder (BPD) show marked impairment in overall personality functioning, with the deepest disruption in how they experience themselves, according to a new study published in Borderline Personality Disorder and Emotion Dysregulation. The research also finds that the severity of that impairment is most closely tied to self-reported mentalizing difficulties and to reduced performance on selected neurocognitive tasks, particularly verbal memory and interference control.

The study, led by Fanni Felletár, with Ildikó Hoffmann and Zsolt Szabolcs Unoka, set out to characterize how three domains long implicated in BPD—personality functioning, mentalization and neurocognition—pattern together, and how each relates dimensionally to personality functioning severity. The authors note that these joint patterns and their dimensional associations had remained insufficiently characterized.

Sixty-five psychiatric inpatients with BPD and 58 healthy controls took part. Each completed the Level of Personality Functioning Scale-Self Report, the Mentalization Questionnaire, the Imposing Memory Task, and a neurocognitive battery covering interference control, cognitive flexibility, verbal memory and event sequencing. Group differences were examined with covariate-adjusted generalized linear and mixed-effects models, while dimensional associations with personality functioning were tested using hierarchical linear regression.

On the categorical comparison, the BPD group showed substantially greater self-mentalizing difficulties than controls. Performance-based theory-of-mind reasoning, however, showed no significant group difference—a divergence the authors highlight between how people report their mentalizing and how they perform on structured reasoning tasks.

Across neurocognitive domains, the BPD group performed worse on interference control, cognitive flexibility, verbal memory and event sequencing. Task-level analyses pointed to poorer latency-based interference control, more frequent set loss, lower immediate verbal episodic memory and poorer event sequencing.

A key question was which of these differences persist once personality functioning severity is taken into account. After adjustment for personality functioning, cognitive flexibility was the only neurocognitive domain that remained significantly associated with diagnostic group. That residual group difference, however, was no longer significant after the researchers additionally adjusted for psychotropic medication burden, suggesting that poorer cognitive flexibility may partly reflect medication effects rather than BPD itself.

The dimensional analyses told a complementary story. Greater personality functioning impairment was strongly associated with higher self-reported mentalizing difficulties, and with poorer interference control and verbal memory after demographic adjustment. When diagnostic group was added to the models, the verbal-memory association remained significant, whereas the interference-control association was attenuated to non-significance. Poorer event sequencing, the authors suggest, may reflect variance shared between diagnostic status and personality functioning severity.

The authors conclude that BPD is characterized by marked impairment in personality functioning, particularly in self-functioning, and that the dimensional severity of that impairment is most closely related to self-reported difficulties in self-mentalizing and to reduced performance in selected neurocognitive domains, especially verbal memory and interference control. In their framing, personality functioning severity and categorical BPD status show overlapping yet non-identical mentalizing and neurocognitive correlates.

The findings support a differentiated account of cognition and self-experience in BPD: self-reported mentalizing difficulty and verbal memory performance track the continuum of personality functioning, while other cognitive differences appear to depend on diagnostic status, medication burden, or shared variance. The study was published as open access research on 24 September 2026, and the version shared at publication is subject to further editorial edits before the final Version of Record appears.

Subject of Research: Dimensional associations between personality functioning, mentalization and neurocognition in borderline personality disorder

Article Title: Personality functioning as a dimensional context for mentalization and neurocognition in borderline personality disorder

Article References: Felletár, F., Hoffmann, I., & Unoka, Z. S. (2026). Personality functioning as a dimensional context for mentalization and neurocognition in borderline personality disorder. Borderline Personality Disorder and Emotion Dysregulation. https://doi.org/10.1186/s40479-026-00372-0

Image Credits: AI Generated

DOI: 10.1186/s40479-026-00372-0

Keywords: borderline personality disorder, personality functioning, mentalization, neurocognition, verbal memory, interference control, cognitive flexibility, theory of mind, self-functioning, psychotropic medication, Personality, functioning