Mentalization-based therapy adherence and competence stimulates in-session mentalization in psychotherapy for borderline personality disorder with co-morbid substance dependence.

MBT adherence and competence were significantly related to patient in-session mentalizing, supporting the validity of MBT principles. Results point to the importance of supervision for therapists to become adherent to MBT principles. The small number of patients and sessions limits generalizability of results.