Abstract: Even though Major Depressive Disorder (MDD) is the leading cause of disability worldwide impacting over 300 million individuals, early detection and intervention is hindered by the limited knowledge of its underlying mechanisms. One association found to be significant within MDD is the presence of early life stress (ELS), such as sexual abuse, emotional abuse and family conflict. However, the biological mechanism linking ELS and MDD are unknown. To properly assess the function consequences of ELS within MDD and address these open questions, we propose an analysis of the metabolism of AMY, ACC, HIP, and DLPFC through FDG PET in addition to a structural MRI in MDD patients with and without ELS. We hypothesize that in MDD patients with prior history of ELS, Evaluation of Brain Structure and Function in Currently Depressed Adults with a History of Early Life Stress Joshua Jones compared to those without ELS, will have a smaller volume/cortical thickness as measured by MRI and decreased metabolism as measured by PET scans in the bilateral DLPFC, ACC, HIP, and AMY. This study would for the first time, assess both structure and function of critical regions of the HPA axis in MDD, while accounting for the common confounder of ELS.

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