Towards optimal treatment for borderline personality disorder Comparative effectiveness, treatment selection, and assessment

Borderline personality disorder (BPD) is a severe mental disorder associated with substantial personal and societal burden. This thesis aimed to optimize BPD treatment by (1) evaluating the comparative effectiveness of Dialectical Behavior Therapy (DBT) and Schema Therapy (ST), (2) advancing personalized treatment selection, and (3) strengthening assessment. The thesis centers on the multicenter Borderline Optimal Treatment Selection (BOOTS) randomized clinical trial, in which 204 outpatients with BPD received DBT or ST and were followed for three years.
A burden-of-disease study demonstrated impaired quality of life and high societal costs among individuals with BPD, underscoring the importance of effective treatment. The clinical effectiveness study showed that both DBT and ST were associated with substantial improvements across clinical and psychosocial outcomes, with no significant differences in effectiveness. In the economic evaluation, no significant differences were found in societal costs or health outcomes, although conclusions regarding cost-effectiveness varied by outcome measure.
Regarding personalized treatment selection, machine-learning analyses provided preliminary evidence of differential treatment response, with several patient characteristics emerging as potential indicators of differential benefit from DBT versus ST. Comorbid substance use disorder generally did not moderate treatment outcomes, while effects on substance use were limited overall.
Finally, the Ultrashort BPD Checklist showed satisfactory psychometric properties for screening and monitoring BPD symptoms. The Dutch DBT Ways of Coping Checklist showed promising psychometric properties for assessing DBT skills use and dysfunctional coping, although further refinement is warranted.
Overall, DBT and ST both appear to be viable treatment options for BPD, while improved assessment and personalized treatment selection may further optimize outcomes.