Sustainability of Mentalization‐Based Treatment Programs for Poorly Functioning Patients With Borderline Personality Disorder. Can We Really Keep It Up?

Though positive effects of mentalization-based treatment (MBT) for patients with severe borderline personality disorder (BPD) are increasingly documented, less is known about the sustainability of specialized treatment standards and the maintenance of positive outcomes over time. This study aimed to investigate the organizational and clinical sustainability of an outpatient MBT program across two successive treatment periods. The study compares outpatients referred to MBT in a tertiary-level, specialist mental health service in 2009-2011 (Period I: n = 96) versus 2011-2015 (Period II: n = 89). Organizational quality was based on the MBT quality manual (2019). By structured clinical interviews and repeated self-reports, comparisons included baseline characteristics of eligible patients, clinical outcomes during treatment, therapeutic alliance, therapist countertransferences, and treatment adherence. The MBT team, organization, and systems for quality assurance held satisfactory standards and stability across the two time periods largely compatible with manual recommendations. Patient selection to MBT was in accordance with the targeted patient group, admitting poorly functioning young adults with BPD in both periods. Period II included patients with more severe BPD and self-harming behaviors. Clinical improvement rendered effect sizes in the large range irrespective of time period, and overall 70% remission rates of self-harming. Patient-reported alliance to therapists and therapist-reported countertransference responses were stable with satisfactory levels in both periods. Both periods had low rates of drop-out, though higher in Period II. Results support positive effects and sustainability of MBT for poorly functioning BPD patients treated in a tertiary outpatient MBT-unit within a supportive and stable organizational environment.