Randomised, placebo‑controlled, triple‑blind Phase II study (n=38) testing single IV ketamine doses (0.1–0.5 mg/kg) with MRI to measure glutamate and GABA in major depressive disorder; optional second 0.5 mg/kg infusion offered to non‑responders.
Randomised, placebo-controlled, triple-blind parallel study in patients with major depressive disorder using single intravenous ketamine doses (0.1–0.5 mg/kg) with magnetic resonance spectroscopy to measure glutamate and GABA before and during infusion.
Primary objective is dose-finding to relate ketamine-induced changes in Glu and GABA to antidepressant response; healthy control cohort received a single 0.5 mg/kg infusion and one MRI/infusion session for comparison.
Ketamine or saline was infused over 40 minutes with a 90-minute MRI scan during infusion; non-responders could be offered an optional second 0.5 mg/kg infusion and scan.
IV ketamine 0.1 mg/kg infusion with MRI during infusion.
Infusion over 40 minutes; MRI (90 min) during infusion.
IV ketamine 0.2 mg/kg infusion with MRI during infusion.
Infusion over 40 minutes; MRI (90 min) during infusion.
IV ketamine 0.3 mg/kg infusion with MRI during infusion.
Infusion over 40 minutes; MRI (90 min) during infusion.
IV ketamine 0.4 mg/kg infusion with MRI during infusion.
Infusion over 40 minutes; MRI (90 min) during infusion.
IV ketamine 0.5 mg/kg infusion with MRI during infusion.
Infusion over 40 minutes; MRI (90 min) during infusion. Optional second 0.5 mg/kg infusion and scan offered to non-responders.
Saline placebo infusion with MRI during infusion.
Saline infusion over 40 minutes; MRI (90 min) during infusion.