BackgroundPersonal agency- the degree to which one believes they have control over their life- is thought to influence how people understand their interpersonal relationships. Links between adult attachment and personal agency are theoretically relevant to the experience of borderline personality disorder (BPD) but this has yet to be empirically examined. The present research examines the impact of personal agency and adult attachment styles for individuals meeting criteria for BPD.MethodsParticipants consented to an online community study examining measures of locus of control (as an index of personal agency), BPD, and adult attachment. Participants meeting criteria for BPD (N = 96; mean age = 30.63; 70.5% female) were compared to age-matched healthy controls (N = 96; mean age = M = 31.99; 89.0% female).ResultsIndividuals who met criteria for BPD displayed lower personal agency and higher fearful and preoccupied attachment styles in their close relationships, compared to Controls. Controls reported greater personal agency and were more securely attached in their relationships. Using multiple mediation modeling, the indirect effect of personal agency on BPD was significant for preoccupied, fearful, and secure attachment, but was non-significant for dismissive attachment. Lower personal agency was associated with insecure adult attachment styles.ConclusionsFindings highlight the previously unexplored relationship between BPD and personal agency and indicate that adult attachment style plays a significant role. Low personal agency may increase challenges for individuals with symptoms of BPD by exacerbating relationship difficulties. People in treatment for BPD may benefit from focusing on both relationship insecurity and its impact on their perceived personal control.

Background Low personal agency is the concept of attributing successes and failures to external factors rather than personal characteristics. Previous research supported links between low personal agency and symptoms of borderline personality disorder (BPD). The present research followed patients in an outpatient dialectical behavioural therapy (DBT) group from intake to 12 months follow up to examine the impact of personal agency on outcome. Methods Patients (N = 57, age 18–72, 91.5% female) were assessed at intake, after three months of DBT treatment, and 12 months follow up on measures of symptoms and personal agency. Three separate measures were used to assess treatment outcomes: the BPD Checklist, the Personality Inventory for DSM-5 (PID-5), and the Mental Health Inventory (MHI-5). Results Mixed model analyses found BPD symptoms significantly reduced as a result of DBT treatment and were maintained at follow-up. However, 47% of participants continued to meet BPD criteria 12 months later, despite treatment. Regression analyses indicated that low personal agency at intake was associated with higher BPD symptom severity at post-treatment and 12 month follow up. In addition, low personal agency at intake was associated with greater levels of negative affectivity at post-treatment. Personal agency did not relate to levels of depression and anxiety. Conclusions Despite the reductions in BPD symptomology, personal agency did not significantly change over time. Those with lower agency at intake continued to do more poorly at follow up. We speculate that poor outcomes may be contributed to by patients' lack of engagement in recovery due to poor agency and an external locus of control. As such, therapeutic approaches, like DBT, may require additional strategies to appropriately target low personal agency. Further research is needed to understand if other treatment protocols may facilitate positive change in personal agency.