Randomised, double-blind, placebo-controlled parallel trial (n=51 actual) testing repeated IV ketamine infusions (0.5 mg/kg, six 40-minute infusions) for depression in people with Parkinson's disease.
Parallel-group, randomised, quadruple-blind RCT comparing six intravenous ketamine infusions (0.5 mg/kg over 40 minutes) with saline placebo in participants with Parkinson's disease and major depressive disorder. Primary outcome is reduction in depression severity.
A subset will undergo baseline and post-treatment PET (synaptic density) and fMRI (functional connectivity) to examine mechanistic effects and network reorganisation underlying ketamine's antidepressant effect in PD.
Six IV ketamine infusions (0.5 mg/kg over 40 minutes) with cardiac monitoring.
0.5 mg/kg per infusion, administered over 40 minutes; up to 60 mg total per infusion as capped in protocol.
Six IV saline (placebo) infusions administered over 40 minutes with monitoring.
Saline IV over 40 minutes (placebo comparator).