Economic evaluation of three forms of early intervention for young people with borderline personality disorder: a within-trial cost-utility analysis from the MOBY clinical trial

Borderline personality disorder (BPD) is a severe mental disorder that begins in adolescence and emerging adulthood. This study evaluated the comparative cost-effectiveness of three forms of early intervention, each with differing levels of treatment complexity, for young people with recently-diagnosed BPD. A cost-utility analysis was conducted alongside the Monitoring Outcomes of BPD in Youth (MOBY) randomised controlled trial involving 139 Australian participants, aged 15–25 years, who were diagnosed with BPD. The three MOBY treatment arms (from highest-to-lowest treatment complexity) were: (1) HYPE + CAT, the Helping Young People Early (HYPE) dedicated BPD service model for young people, combined with weekly Cognitive Analytic Therapy; (2) HYPE + Bef, HYPE combined with a weekly befriending psycotherapy control condition; and (3) YMHS + Bef, a general youth mental health service model, combined with Befriending. Cost and outcomes data were collected over 18 months, with costs denominated in 2015 Australian dollars (Ah$), and quality-adjusted life year (QALY) outcomes derived using the Assessment of Quality of Life-8D questionnaire. Cost-effectiveness results were expressed as an incremental cost-effectiveness ratio (ICER). There were no significant differences between the three treatment arms in costs or QALYs. The three treatment arms demonstrated similar levels of cost-effectiveness to one another. Under a willingness-to-pay threshold of A$96,000 per QALY, the probability of each intervention being cost-effective (when assuming mutual exclusivity) was: 36.4% for HYPE + CAT; 30.9% for HYPE + Bef; and 32.7% for YMHS + Bef. For young people with recently-diagnosed BPD, and who have never received evidence-based BPD treatment, early intervention has the potential to represent good value for money. Both specialist and generalist service models appear to be similarly cost-effective.