Background: Longer-term follow-up of patients with borderline personality disorder have found favourable clinical outcomes, with long-term reduction in symptoms and diagnosis.
Aims: We examined the 6-year outcome of patients with borderline personality disorder who were randomised to 1 year of cognitive-behavioural therapy for personality disorders (CBT-PD) or treatment as usual (TAU) in the BOSCOT trial, in three centres across the UK (trial registration: ISRCTN86177428).
Method: In total, 106 participants met criteria for borderline personality disorder in the original trial. Patients were interviewed at follow-up by research assistants masked to the patient's original treatment group, CBT-PD or TAU, using the same measures as in the original randomised trial. Statistical analyses of data for the group as a whole are based on generalised linear models with repeated measures analysis of variance type models to examine group differences.
Results: Follow-up data were obtained for 82% of patients at 6 years. Over half the patients meeting criteria for borderline personality disorder at entry into the study no longer did so 6 years later. The gains of CBT-PD over TAU in reduction of suicidal behaviour seen after 1-year follow-up were maintained. Length of hospitalisation and cost of services were lower in the CBT-PD group compared with the TAU group.
Conclusions: Although the use of CBT-PD did not demonstrate a statistically significant cost-effective advantage, the findings indicate the potential for continued long-term cost-offsets that accrue following the initial provision of 1 year of CBT-PD. However, the quality of life and affective disturbance remained poor.