The Effectiveness of 6 versus 12 Months of Dialectical Behavior Therapy for Borderline Personality Disorder: A Noninferiority Randomized Clinical Trial

Introduction: Evidence-based psychotherapies for borderline personality disorder (BPD) are lengthy, posing a barrier to their access. Brief psychotherapy may achieve comparable outcomes to long-term psychotherapy for BPD. Evidence is needed regarding the comparative effectiveness of short- versus long-term psychotherapy for BPD. Objective: The aim was to determine if 6 months of Dialectical Behavior Therapy (DBT) is noninferior to 12 months of DBT in terms of clinical effectiveness. Methods: This two-arm, single-blinded, randomized controlled noninferiority trial with suicidal or self-harming patients with BPD was conducted at two sites in Canada. Participants (N = 240, M (SD)(age) = 28.27 (8.62), 79% females) were randomized to receive either 6 (DBT-6) or 12 months (DBT-12) of comprehensive DBT. Masked assessors obtained measures of clinical effectiveness at baseline and every 3 months, ending at month 24. DBT-6 and DBT-12 were outpatient treatments consisting of weekly individual therapy sessions, weekly DBT skills training group sessions, telephone consultation as needed, and weekly therapist consultation team meetings. Results: The noninferiority hypothesis was supported for the primary outcome, total self-harm (6 months: margin = -1.94, M-diff [95% CI] = 0.16 [-0.14, 0.46]; 12 months: margin = -1.47, M-diff [95% CI] = 0.04 [-0.17, 0.23]; 24 months: margin = -1.25, M-diff [95% CI] = 0.12 [-0.02, 0.36]). Results also supported noninferiority of DBT-6 for general psychopathology and coping skills at 24 months. Furthermore, DBT-6 participants showed more rapid reductions in BPD symptoms and general psychopathology. There were no between-group differences in dropout rates. Conclusions: The noninferiority of a briefer yet comprehensive treatment for BPD has potential to reduce barriers to treatment access.

Automated summary

The study found that 6 months of Dialectical Behavior Therapy (DBT) is noninferior to 12 months of DBT in terms of clinical effectiveness for borderline personality disorder patients. Participants in the 6-month group showed faster reductions in symptoms and noninferiority in general psychopathology and coping skills at 24 months. There were no differences in dropout rates between the two groups, indicating the potential for a shorter yet comprehensive treatment for BPD to reduce barriers to treatment access.