The Treatment of Depression With Yoga and Walking

Subjects with Major Depressive Disorder (MDD) will be randomized into two treatment groups, a yoga group (YG) and a walking group (WG). After screening and Scan 1, each subject will be randomized to a 12-week yoga or walking intervention consisting of two group sessions and three homework sessions a week.The primary dependent variable will be brain gamma amino-butyric acid (GABA) levels measured using magnetic resonance spectroscopy (MRS) in two regions of interest (ROI)s: the thalamus and the anterior cingulate. GABA levels will be measured three times: Scan 1 prior to randomization, Scan 2 after the 12-week intervention, and immediately after Scan 2, subjects will participate in either the yoga intervention or walking intervention, followed immediately by Scan 3. The secondary dependent variable will be changes in depressive symptoms, mood and anxiety measured by valid and reliable psychological instruments obtained before each scan and at screening, week-4, week-8 and week-12. The third dependent variable will be respiratory sinus arrhythmia (RSA) a component of heart rate variability (HRV) that is an accurately index of vagal influences on the heart. RSA will be measured scan 1, pre and post an intervention session depending on group assignment at week 4, 8 and 12 evaluations, pre and post the yoga or walking intervention between Scan 2 and 3. Aim 1: To complete 22 subjects in the yoga group and 22 subjects in the walking group for a total of 44 subjects with Major Depressive Disorder (MDD). Completion is defined at a baseline evaluation, a week-4 or week-8 evaluation and a week-12 evaluation with usable thalamic data for Scans 1, 2 and 3. Aim 2. To measure changes in GABA levels over time using a mixed linear model analogue of repeated measures analysis-of-variance with independent groups in regional GABA levels in MDD subjects assigned to yoga and walking interventions. Aim 3. To assess changes in psychological measurements and regional GABA levels over the course of the interventions using linear regression. Aim 4. To assess changes in PNS using Respiratory Sinus Arrhythmia (RSA) over the course of the study using linear regression. Aim 5. To assess changes in PNS, RSA and regional GABA levels over the course of the study using linear regression.