 This study will focus on early translation of Dr. Fryer and Dr. Chias research and will bring the gut-brain interface to the field of individualizing treatment to patients who struggle with depression. This project will provide insight into how gut microbiota may be implicated in depression, how antidepressant treatments alter microbiota composition, and how these factors impact key physiologic mediators of depression i.e. cortisol and cytokine levels. The public health implications of more focused drug development and treatment for depression are substantial. 