S0033291718000132jra 2522..2529

Background. Day hospital mentalization-based treatment (MBT-DH) is a promising treatment for borderline personality disorder (BPD) but its evidence base is still limited. This multi-site randomized trial compared the efficacy of MBT-DH delivered by a newly set-up service v. specialist treatment as usual (S-TAU) tailored to the individual needs of patients, and offered by a well-established treatment service. Methods. Two mental healthcare institutes in The Netherlands participated in the study. Patients who met DSM-IV criteria for BPD and had a score of ⩾20 on the borderline personality disorder severity index (BPDSI) were randomly allocated to MBT-DH (N = 54) or S-TAU (N = 41). The primary outcome variable was the total score on the BPDSI. Secondary outcome variables included symptom severity, quality of life, and interpersonal functioning. Data were collected at baseline and every 6 months until 18-month follow-up, and were analyzed using multilevel analyses based on intention-to-treat principles. Results. Both treatments were associated with significant improvements in all outcome variables. MBT-DH was not superior to S-TAU on any outcome variable. MBT-DH was associated with higher acceptability in BPD patients compared v. S-TAU, reflected in significantly higher early drop-out rates in S-TAU (34%) v. MBT-DH (9%). Conclusions. MBT-DH delivered by a newly set-up service is as effective as specialist TAU in The Netherlands in the treatment of BPD at 18-month follow-up. Further research is needed to investigate treatment outcomes in the longer term and the cost-effectiveness of these treatments.