Integrating Ketamine Effects on Neuronal Molecular Signatures and the Brain Functional and Structural Connectome

Participants in this study will have been diagnosed with major depressive episode (MDE) and have not received any psychiatric treatment for at least 2 weeks (5 weeks if on fluoxetine).Patients will receive intravenous ketamine as the only study drug treatment for the 2 weeks of the study. Magnetic Resonance Imaging (MRI) will be used to measure effects of ketamine on brain structure, function and chemistry, in addition to a soft-nasal brushing procedure to obtain olfactory sensory neurons which will provide the ability to profile in vivo how neurons may react to KET treatment in depressed patients.