S0033291720002123jra 1..11

Background. Two types of mentalization-based treatment (MBT), day hospital MBT (MBTDH) and intensive outpatient MBT (MBT-IOP), have been shown to be effective in treating patients with borderline personality disorder (BPD). This study evaluated trajectories of change in a multi-site trial of MBT-DH and MBT-IOP at 36 months after the start of treatment. Methods. All 114 patients (MBT-DH n = 70, MBT-IOP n = 44) from the original multicentre trial were assessed at 24, 30 and 36 months after the start of treatment. The primary outcome was symptom severity measured with the Brief Symptom Inventory. Secondary outcome measures included borderline symptomatology, personality and interpersonal functioning, quality of life and self-harm. Data were analysed using multilevel modelling and the intention-to-treat principle. Results. Patients in both MBT-DH and MBT-IOP maintained the substantial improvements made during the intensive treatment phase and showed further gains during follow-up. Across both conditions, 83% of patients improved in terms of symptom severity, and 97% improved on borderline symptomatology. No significant differences were found between MBT-DH and MBT-IOP at 36 months after the start of treatment. However, trajectories of change were different. Whereas patients in MBT-DH showed greater improvement during the intensive treatment phase, patients in MBT-IOP showed greater continuing improvement during follow-up. Conclusions. Patients in both conditions showed similar large improvements over the course of 36 months, despite large differences in treatment intensity. MBT-DH and MBT-IOP were associated with different trajectories of change. Cost-effectiveness considerations and predictors of differential treatment outcome may further inform optimal treatment selection. Previous studies have provided evidence for the efficacy of two types of mentalization-based treatment (MBT) for borderline personality disorder (BPD): day hospital MBT (MBT-DH), a treatment involving day hospitalization of patients 5 days per week, and intensive outpatient MBT (MBT-IOP), an outpatient treatment program conducted 2 days per week (Bales et al., 2012, 2014; Barnicot & Crawford, 2019; Bateman & Fonagy, 1999, 2001, 2008, 2009; Jørgensen et al., 2013, 2014; Kvarstein et al., 2015; Laurenssen et al., 2018). However, only one trial has directly compared the two treatment programs. Smits et al. (2019) found that both MBT-DH and MBT-IOP were associated with substantial improvements on both primary and secondary outcome measures, representing moderate-to-large effect sizes 18 months after the start of treatment. Although MBT-DH was not superior to MBT-IOP in terms of changes on the primary outcome measure (symptom severity), MBT-DH showed a trend towards superiority on secondary outcome measures, particularly on measures of relational functioning. Longer-term follow-up data are thus needed to further determine the relative efficacy of MBT-DH and MBT-IOP. https://doi.org/10.1017/S0033291720002123 Downloaded from https://www.cambridge. org/core. Erasmus MC Rotterdam, on 23 Jul 2020 at 08:35:28, subject to the Cambridge Core terms of use, available at https://www.cambridge. org/core/terms. As MBT aims to improve mentalizing, and improvements in mentalizing are thought to underlie ‘broaden-and-build’ cycles leading to improved emotion regulation, feelings of autonomy and agency, and improved capacity for relatedness (Fredrickson, 2001; Luyten & Fonagy, 2014), patients in MBT are expected to show ongoing improvement after treatment termination. Consistent with this hypothesis, previous follow-up studies have shown that the gains made during the intensive treatment phase of MBT-DH were maintained and that patients continued to improve over 18-month and 5-year follow-up periods for the MBT-DH program (Bales et al., 2014; Bateman & Fonagy, 2001, 2008), although for MBT-IOP, ongoing improvement was not found in one 18-month follow-up study (Jørgensen et al., 2014). Several studies have focused on the impact of treatment modality or intensity on treatment outcome in BPD. For instance, a non-randomized study by Bartak et al. (2011) investigated the differential effectiveness of three treatment modalities (inpatient, day hospital and outpatient treatment) and consequent varying degrees of treatment intensity for cluster B personality disorders, yielding somewhat inconclusive results. Although patients improved in all treatment modalities, at 18-month follow-up, inpatient treatment was associated with marginally significant better outcomes in terms of psychiatric symptoms, compared with outpatient treatment. There were no differences in terms of quality of life and interpersonal functioning (Bartak et al., 2011). At 60-month follow-up, inpatient treatment was associated with slightly better outcomes compared with outpatient treatment in terms of quality of life, but not on other outcome measures (Horn et al., 2016). Another non-randomized study, by Chiesa, Fonagy, Holmes, and Drahorad (2004), showed significantly better outcomes in a heterogeneous sample of patients with personality disorder in a step-down program compared with longer-term inpatient treatment and general psychiatric services. At 1and 2-year follow-up, patients in the step-down group showed a greater improvement in symptom severity, social functioning and self-harming behaviours and reported less use of outpatient treatment and readmissions to psychiatric services after discharge. These findings were maintained at 6-year follow-up (Chiesa, Fonagy, & Holmes, 2006). Nevertheless, a more recent meta-analysis of psychotherapy for BPD by Cristea et al. (2017) found that neither treatment duration nor treatment intensity was related to treatment outcome. A number of recent randomized controlled trials are addressing the issue of treatment intensity (Juul et al., 2019; McMain et al., 2018), but these studies are still ongoing. Clearly, more research in this area is needed. The current paper reports on the findings at 3-year follow-up from the abovementioned randomized clinical trial comparing MBT-DH and MBT-IOP for patients with BPD (Smits et al., 2019). Because MBT-DH and MBT-IOP differ markedly in terms of treatment intensity, we expected that the tendency for MBT-DH to be superior to MBT-IOP would be more pronounced at 36-month follow-up, given the substantially higher dose of treatment.