The clinical and cost effectiveness of quetiapine for people with borderline personality disorder: A pragmatic, double-blind, placebo-controlled, randomised trial
Borderline personality disorder
Participants will be randomised (ratio 1:1) via a secure, 24-hour, web-based randomisation system controlled centrally by the LCTC to receive either quetiapine or matched placebo. Route of administration: oral IMP: Quetiapine prolonged release tablets (overencapsulated) in 50mg and 150mg. Dose: 150mg daily. Participants will be up titrated to this regime as follows: Week 1 – 50mg daily, Week 2- 100mg daily, Week 3 and onwards: 150mg daily Higher or lower doses will be permitted according to clinical response and tolerability (minimum dose of 50mg daily and maximum dose of 750mg daily) Placebo: Overencapsulated capsules filled with lactose to match IMP, in 50mg and 150mg. Dose: Same as IMP Trial treatment duration is 12 months
Current key inclusion criteria as of 03/10/2025: 1. Aged ≥18 years 2. Able to provide written and informed consent and agreement to comply with the requirements of the trial 3. In contact with secondary care mental health services 4. Contraception is to be used for the duration of the trial 5. Meet diagnostic criteria for borderline personality disorder using the Structured Clinical Interview for DSM-V Personality Disorders (SCID-5) 6. A ZAN-BPD total score of ≥9 at the time of randomisation 7. Ability to speak and read English Previous key inclusion criteria: 1. Aged ≥18 years 2. Able to provide written and informed consent and agreement to comply with the requirements of the trial. 3. In contact with secondary care mental health services. 4. Meet diagnostic criteria for borderline personality disorder using the Structured Clinical Interview for DSM-V Personality Disorders (SCID 5). 5. A ZAN-BPD total score of ≥9 at the time of randomisation. 6. Ability to speak and read English 7. Able to swallow IMP whole
Current exclusion criteria as of 21/01/2026: 1. Prescribed an antipsychotic medication (oral or intramuscular) within two weeks of baseline assessments 2. Have a current clinical diagnosis of schizophrenia, bipolar I or bipolar II disorder 3. Pregnant, trying to conceive and/or breastfeeding 4. Women of childbearing potential who are unable or unwilling to use a highly effective method of contraception for the duration of the trial 5. Known hypersensitivity to quetiapine or to any of the excipients of the XL formulation 6. Concomitant administration of erythromycin, clarithromycin or nefazodone within 14 days 7. Concomitant administration of cytochrome P450 3A4 inhibitors, such as anti-fungal medicines: (itraconazole, ketoconazole, voriconazole, posaconazole); medicines used to treat cancer: idelalisib, tucatinib, ceritinib; medicines used to treat HIV: atazanavir, cobicistat, darunavir, fosamprenavir, lopinavir, ritonavir, saquinavir, tipranavir 8. History of QTc prolongation, including congenital long QT syndrome, severe neutropenia, agranulocytosis, history of cardiovascular disease (angina, stroke, myocardial infarction, arrythmia, congestive cardiac failure, heart hypertrophy) 9. Unable/refusal to undertake blood tests 10. Clinically significant findings that, in the opinion of the investigator, are contraindicated for inclusion in the study 11. Unable to swallow IMP whole 12. Individuals who are being investigated for or have a confirmed diagnosis of dementia (any kind) Previous exclusion criteria as of 03/10/2025: 1. Prescribed an antipsychotic medication within 2 weeks of baseline assessments 2. Have a current clinical diagnosis of schizophrenia, bipolar I or bipolar II disorder 3. Pregnant, trying to conceive and/or breastfeeding 4. Women of childbearing potential who are unable or unwilling to use a highly effective method of contraception for the duration of the trial 5. Known hypersensitivity to quetiapine or to any of the excipients of the XL formulati