Ketamine for Veterans With Parkinson's Disease

Parkinson's disease (PD) is a devastating illness that has a growing impact on Veterans. One of the most disabling symptoms is depression, which is common in PD and linked to poor quality of life and higher risk of suicide. Unfortunately, there is a lack of effective treatments for depression in PD. Ketamine, which has rapid and potent antidepressant effects, is a potential option but has not been tested in Veterans with PD. Studies in rodents show that ketamine may not only improve depression in PD, it may target two of the underlying drivers of the disease: (1) reduced neuroplasticity, or the brain's ability to adapt and remodel itself; and (2) elevated inflammation. The investigators are conducting a randomized, placebo-controlled study to examine if a dose of intravenous (IV) ketamine improves depression in Veterans with PD. The investigators will also examine ketamine's effects on neuroplasticity and inflammation, which will help us understand how ketamine works in PD and if it can be a useful treatment for Veterans with the disease. This study will lay groundwork for a larger clinical trial across multiple VA sites.