The MDPU case report form will gather information on the participant's course of illness variables. Conventional pharmacological treatments for MDD will be permitted (e.g., conventional antidepressants). Conventional unimodal antidepressants modulate cerebral glucose metabolism; as such, they will be kept consistent throughout the duration of the study and will not be altered from the point of randomization to study endpoint. Antidepressants and augmentation strategies with significant anti-cholinergic potential (e.g., paroxetine, tricyclic antidepressants) as well as benzodiazepines will be exclusionary as they may negatively affect neurocognitive function.