A COMPREHENSIVE SYSTEMATIC REVIEW: DIALECTICAL BEHAVIOUR THERAPY (DBT) AS THE GOLD-STANDARD PSYCHOTHERAPY FOR BORDERLINE PERSONALITY DISORDER

Introduction: Borderline personality disorder (BPD) is a severe psychiatric condition with lifetime prevalence of 0.7-2.7% and suicide rate approaching 8-10%. Dialectical behaviour therapy (DBT), the first manualised psychotherapy developed for chronically suicidal BPD patients, is widely designated the gold-standard psychosocial treatment. This review synthesised primary evidence across all outcome domains to determine whether the evidence supports this designation. Methods: The study strictly adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines. Eligible designs comprised RCTs, controlled non-randomised trials, cohort, case-control, cross-sectional and observational studies evaluating DBT in BPD populations. Systematic reviews were excluded from primary tabulation but retained for contextualisation. Two reviewers independently screened, extracted data and appraised risk of bias using RoB 2, ROBINS-I and Newcastle-Ottawa Scale; certainty graded with GRADE. Synthesis was narrative with structured vote-counting across seventeen outcome domains. Results: Sixty primary studies (up to 2026) encompassing >3,400 participants across 13 countries were included: 34 RCTs, 4 controlled non-randomised trials, 12 prospective cohorts, 4 retrospective studies, 4 mediation analyses and 2 economic evaluations. Statistically significant DBT benefits were demonstrated for non-suicidal self-injury and total self-harm, suicide attempts (hazard ratio 2.66 favouring DBT versus expert therapy, p=0.005), treatment retention (hazard ratio 3.2, p<0.001), psychiatric hospitalisation (up to 89% reduction in hospital days), emotion dysregulation, depressive symptoms, anger, comorbid substance use and PTSD, quality of life, medication load and cost-effectiveness. In head-to-head comparisons against other structured psychotherapies—general psychiatric management, schema therapy, mentalisation-based treatment, conversational model, CAMS—DBT produced large within-group improvements statistically equivalent rather than superior. Durability extended to 12.4 years in adolescent trials. Risk of bias was low in 30%, moderate in 50%, high in 20%; GRADE certainty was moderate for self-harm and retention, low for most other domains. Discussion: DBT demonstrates coherent, reproducible benefit across behavioural, affective, functional, service-utilisation and economic domains, sustained over follow-up exceeding a decade. Mechanistic evidence converges on emotion regulation capacity, behavioural skills acquisition, hopelessness reduction and validating therapeutic relationship as operative pathways. The principal qualification is equivalence, not superiority, against other well-specified BPD-specific psychotherapies; DBT's gold-standard status rests on breadth, replication, transportability and unique replicated effect on suicidal behaviour, not on demonstrated superiority over all active specialist comparators. Conclusion: DBT is supported by the largest, longest and most methodologically diverse primary evidence base of any BPD psychotherapy, with significant benefits across seventeen outcome domains. The gold-standard designation is empirically defensible as reference-standard status against usual and non-specialist care, and as equal-first-line among structured disorder-specific psychotherapies. Priorities include adequately powered equivalence trials, trials in male and culturally diverse populations, evaluation of briefer and digitally delivered formats, and implementation research in low- and middle-income settings.