Population-based cost-offset estimation for the treatment of borderline personality disorder: projected costs in a currently running, ideal health system.

Borderline personality disorder (BPD) is considered one of the most expensive mental disorders in terms of direct and indirect costs. The aim of this study was to carry out a cost-offset estimation of disorder-specific psychotherapy for BPD at the population level. The study investigated whether the possible financial benefits of dialectical behavior therapy outweigh the therapy costs, assuming a currently running, ideal health system, and whether the estimated cost-benefit relationships change depending upon the number of patients willing to be treated. A formula was elaborated that allows the user to calculate cost-benefit relationships for various conservative or progressive scenarios, with different stages of individuals' willingness to be treated (10%-90%). The possible costs and benefits of BPD-related treatment were evaluated using a 12-month, prevalence-based approach. The annual costs for untreated BPD were 8.69 billion EUR annually. The cost-benefit relationship for the treatment remained constant at 1.52 for all scenarios, implying that for each EUR invested, 1.52 EUR can be gained within one year, independent of the willingness to be treated. Additional intangible benefits were calculated with the aid of Quality-Adjusted Life Years. Findings suggest that BPD-related treatment might well be efficient at the population level.