This open-label, Phase II/III trial (n=36) will study the effects of ketamine (0.5 mg/kg IV infused over 40 minutes, four infusions over two weeks) on suicidal ideation in individuals with major depressive disorder (MDD).
Prospective, open-label single-group study delivering four intravenous ketamine infusions (0.5 mg/kg over 40 minutes) administered twice weekly across two weeks to participants with MDD and active suicidal ideation.
Primary outcomes assess change in suicidal ideation and associated clinical scales; neurobiological mechanisms are examined using advanced diffusion MRI pre-treatment and 24 hours after the fourth infusion.
A mixed-methods approach includes repeated clinical assessments and brief qualitative interviews within 72 hours post-treatment to capture patient-perceived changes in suicidal thinking; target sample size informed by diffusion MRI effect-size considerations.
Open-label single-group treatment: four IV ketamine infusions over two weeks.
0.5 mg/kg infused over 40 minutes; four infusions over two weeks.