Rosie James - Institutionen för kliniska vetenskaper, Malmö

Title: Navigating the Self in Borderline Personality Disorder: Identity Disturbance, Non-Suicidal Self-Injury, Help-Seeking, and Diagnostic Identification

Main supervisor: Sofie Westling

Reviewers: Lisa Ekselius, Vendela Zetterqvist, Johan Nyrenius 

Abstract

Background

Identity disturbance is a central yet underexplored feature of borderline personality disorder (BPD). This disorder is strongly associated with non-suicidal self-injury (NSSI), affecting up to 80% of individuals, and a lifetime suicidality of approximately 10%. Using a multidimensional model of identity functioning, this thesis examines how Lack of Identity—defined as a diminished or incoherent sense of self—shapes key stages of the mental health trajectory. Across four studies and two data collections, this thesis combines large-scale quantitative data with interviews to examine the role of Lack of Identity across NSSI onset, help-seeking and diagnostic identification. 

Research questions

(1) How do identity dimensions relate to NSSI and BPD traits in university students? (2) Does Lack of Identity predict NSSI initiation over time? (3) What borderline symptom subgroups exist, and how do they differ in help-seeking for NSSI? (4) How do individuals with BPD identify with their diagnosis, and how can this inform symptom management?

Preliminary results

Study I showed that the Swedish translation of the Self-Concept and Identity Measure is valid and reliable. Lack of Identity was most strongly associated with NSSI, BPD traits, and general psychopathology. Study II found that Lack of Identity predicted both initiation and reinitiation of NSSI but not continued engagement among individuals already self-injuring. Study III identified BPD symptom profiles and showed that an internalizing profile (high identity disturbance and emptiness) received less encouragement to seek help despite comparable NSSI levels; encouragement was the strongest predictor of actual help-seeking. Study IV interviews have been collected and transcribed; analysis and scale development are ongoing.

Significance

Together, these findings suggest that an absent or incoherent sense of self plays a central role in NSSI onset and early pathways to BPD identification, particularly through differences in encouragement towards help-seeking. This perspective may also extend to how individuals integrate a BPD diagnosis into their identity, with implications for how the diagnosis is understood and communicated. By centering Lack of Identity as a unifying construct, this thesis reframes identity disturbance from a descriptive symptom to a candidate mechanism in the emergence and clinical trajectory of BPD.

Published study included in the thesis

James, R., Daukantaité, D., & Nilsson, M. (2023). A validation of the Swedish self-concept and Identity Measure (SCIM) and its association with mental health problems. Heliyon, 9(7), e18151. https://doi.org/10.1016/j.heliyon.2023.e18151 

Studies in review

James, R., Overgaard, R., Westling, S., Nilsson, M. Help-Seeking Patterns for Non-Suicidal Self-Injury Across Borderline Symptom Profiles in a Large Sample of University Students. Manuscript submitted for publication, 2026.

James, R., Thylander, C., Westling, S., Nilsson, M. Lack of Identity and Risk for Onset and Recurrence of Non-Suicidal Self-Injury in Emerging Adulthood. Manuscript submitted for publication, 2026.

Published study not included in the thesis

James, R., Lundgren, E., Daukantaité, D., & Nilsson, M. (2025). From prevalent to personal: how social exposure predicts attitudes toward non-suicidal self-injury and what prevalence reveals. Frontiers in Psychology, 16. https://doi.org/10.3389/fpsyg.2025.1652207