As use of complementary and alternative medicine (CAM) techniques such as yoga increases, it is important that the mechanisms through which yoga exerts its salubrious effects are elucidated. This study assesses the effects of a 12-week yoga intervention on the level of the brain's primary inhibitory neurotransmitter, gamma amino-butyric acid (GABA), using magnetic resonance spectroscopy (MRS). Using MRS, GABA levels have been shown to be low in subjects with depression, anxiety, epilepsy, cocaine dependence, and alcohol dependence. All of these disorders are treated with pharmacologic agents known to increase the activity of the GABA system. Controlled studies have shown that the practice of yoga also decreases symptoms in depression, anxiety, and epilepsy. In a previous study using MRS, experienced yoga practitioners demonstrated a 27% increase in brain GABA levels following a 60-minute yoga session in contrast with a .001% change found in controls after a 60-minute reading session. This suggests that yoga increases brain GABA levels, and should therefore be explored as a therapeutic intervention in disorders in which brain GABA levels are low. This application proposes a longitudinal study of 60 subjects that will be randomized into a yoga group or a reading group. Each group will participate in a 12-week intervention that will be composed of 60- minutes of Iyengar yoga or reading three times a week for a maximum of 36 interventions. Mood scales will be collected at the beginning and end of each session. Individuals will also participate in three imaging sessions comprised of mood scales followed by a MRS scan at the following times: Scan 1 at baseline prior to randomization; Scan 2 after 12-weeks of either a yoga or reading intervention; Scan 3 approximately one hour after Scan 2 during which time subjects will participate in either a 60-minute yoga or reading session depending on the group assignment. This study will explore the following hypotheses: 1) There will be no difference in baseline GABA levels at Scan 1 between the yoga group and the reading group; 2) The yoga group will exhibit a greater increase in brain GABA levels from baseline than the reading group (Scan 2 - Scan 1); 3) The yoga group will exhibit a greater acute increase in GABA levels after the intrascan intervention than the reading group (Scan 3 - Scan 2); 4&5) Pre and Post session mood scales will show greater improvement in mood over the course of the 12-week intervention in the yoga group compared to the reading group; 6) Acute changes in mood scales (Post-Pre) will be greater in the yoga group compared to the reading group; 7) Improvement in mood states and increases in brain GABA levels will be positively correlated. [unreadable] Public Health Relevance: Disorders associated with low brain GABA states such as depression, and anxiety, cost the U.S billions of dollars each year in treatment costs and loss of productivity, not to mention the personal costs to the individual. This study will test the hypothesis that the practice of yoga significantly increases brain GABA levels. If confirmed this would suggest that the risk-to-benefit ratio of exploring the efficacy of yoga as a treatment for low GABA states is excellent, in that the practice of yoga promotes general health, has few side effects if practiced correctly and has no risk of secondary dependencies, which often occur with some pharmacologic treatments. [unreadable] [unreadable] [unreadable]