Objective: This study evaluated the effect of mentalization-based treatment by partial hospitalization compared to treatment as usual for borderline personality disorder 8 years after entry into a randomized, controlled trial and 5 years after all mentalization-based treatment was complete.
Method: Interviewing was by research psychologists blind to original group allocation and structured review of medical notes of 41 patients from the original trial. Multivariate analysis of variance, chi-square, univariate analysis of variance, and nonparametric Mann-Whitney statistics were used to contrast the two groups depending on the distribution of the data.
Results: Five years after discharge from mentalization-based treatment, the mentalization-based treatment by partial hospitalization group continued to show clinical and statistical superiority to treatment as usual on suicidality (23% versus 74%), diagnostic status (13% versus 87%), service use (2 years versus 3.5 years of psychiatric outpatient treatment), use of medication (0.02 versus 1.90 years taking three or more medications), global function above 60 (45% versus 10%), and vocational status (employed or in education 3.2 years versus 1.2 years).
Conclusions: Patients with 18 months of mentalization-based treatment by partial hospitalization followed by 18 months of maintenance mentalizing group therapy remain better than those receiving treatment as usual, but their general social function remains impaired.