This Phase II randomised, quadruple-masked trial (n=120) will study adults aged 18 to 70 years with borderline personality disorder, treatment-resistant major depressive disorder or bipolar disorder, and suicidal ideation, evaluating whether intravenous ketamine plus dialectical behavioural therapy (DBT) reduces suicidal ideation more rapidly and robustly than midazolam plus DBT. The main purpose is to assess change in suicidal ideation severity from baseline to Day 35 using the Modified Scale for Suicidal Ideation (MSSI). All participants will receive DBT for 6 months, starting before the infusions, with weekly individual sessions and the addition of weekly group sessions from Week 5. The experimental arm will receive six intravenous ketamine infusions over 1 month: the first two at 0.5 mg/kg over 40 minutes, infusions 3 and 4 flexibly dosed at 0.5 mg/kg to 0.75 mg/kg, and infusions 5 and 6 flexibly dosed at 0.5 mg/kg to 0.85 mg/kg. The comparator arm will receive six intravenous midazolam infusions over the same period: the first two at 0.02 mg/kg over 40 minutes, infusions 3 and 4 at 0.02 mg/kg to 0.03 mg/kg, and infusions 5 and 6 at 0.2 mg/kg to 0.035 mg/kg. Participants will also complete hospital visits, remote follow-up by call or videocall, and a range of mood, cognitive and behavioural assessments.
The goal of this clinical trial is to learn if intravenous (IV) ketamine with Dialectical Behavioural Therapy (DBT) reduces suicidal ideation in individuals with suicidality who have been diagnosed with Borderline Personality Disorder and either Major Depressive Disorder or Bipolar Disorder. The main question it aims to answer is:
Does IV ketamine and DBT produce more rapid and robust improvements in suicidal ideation (SI) severity between baseline and Day 35 compared to IV midazolam and DBT, as measured by changes in the Modified Scale for Suicidal Ideation (MSSI) scores ?
Researchers will compare six IV ketamine infusions and DBT to an active placebo (a look-alike substance that mimics some of ketamine's effects and not others) and DBT to see if IV ketamine with DBT is more effective at reducing SI severity.
Participants will:
* Complete six infusions of either IV ketamine or IV midazolam
* Take part in 6 months of DBT (includes both weekly one-on-one sessions, and group sessions, starting week 5 of the trial)
* Visit the hospital for scheduled in-person visits
* Join a call or videocall for scheduled remote visits
* Complete a variety of different mood, cognitive and behavioral assessments
All participants in the trial will receive DBT. DBT will begin prior to ketamine infusions and will continue for 6 months of the trial. There will be individual DBT and also group DBT that will begin in Week 5 of the trial. Participants in this arm will receive six infusions of ketamine over a month. The first two infusions will be dosed at 0.5mg/kg over a period of 40 minutes. For infusions 3 and 4, patients will be flexibly dosed between 0.5 mg/kg to 0.75 mg/kg, depending on clinical response to first two infusions. For infusions 5 and 6, participants will be flexibly dosed between 0.5 mg/kg to 0.85 mg/kg.
All participants in the trial will receive DBT. DBT will begin prior to midazolam infusions and will continue for 6 months of the trial. There will be individual DBT and also group DBT that will begin in Week 5 of the trial. Participants in this arm will receive six infusions of midazolam over a month. The first two infusions will be dosed at 0.02 mg/kg over a period of 40 minutes. For infusions 3 and 4, patients will be flexibly dosed between 0.02 mg/kg to 0.03 mg/kg, depending on clinical response to first two infusions. For infusions 5 and 6, participants will be flexibly dosed between 0.2 mg/kg to 0.035 mg/kg.
Unmatched intervention: Midazolam Hydrochloride