THE JOURNAL OF ALTERNATIVE AND COMPLEMENTARY MEDICINE Volume 13, Number 4, 2007, pp. 419–426 © Mary Ann Liebert, Inc. DOI: 10.1089/acm.2007.6338 Yoga Asana Sessions Increase Brain GABA Levels: A Pilot Study CHRIS C. STREETER, M.D., 1–3 J. ERIC JENSEN, Ph.D., 2,3 RUTH M. PERLMUTTER, B.S., 1 HOWARD J. CABRAL, Ph.D., 4 HUA TIAN, M.S., 1 DEVIN B. TERHUNE, M.Sc., 1 DOMENIC A. CIRAULO, M.D., 1,3,5 and PERRY F. RENSHAW, M.D. 1,2,3 ABSTRACT Objectives: The aim of this study was to compare changes in brain -aminobutyric (GABA) levels associ- ated with an acute yoga session versus a reading session. It was hypothesized that an individual yoga session would be associated with an increase in brain GABA levels. Design: This is a parallel-groups design. Settings/location: Screenings, scan acquisitions, and interventions took place at medical school–affiliated centers. Subjects: The sample comprised 8 yoga practitioners and 11 comparison subjects. Interventions: Yoga practitioners completed a 60-minute yoga session and comparison subjects completed a 60-minute reading session. Outcome measures: GABA-to-creatine ratios were measured in a 2-cm axial slab using magnetic resonance spectroscopic imaging immediately prior to and immediately after interventions. Results: There was a 27% increase in GABA levels in the yoga practitioner group after the yoga session (0.20 mmol/kg) but no change in the comparison subject group after the reading session (-0.001 mmol/kg) (t =-2.99, df = 7.87, p = 0.018). Conclusions: These findings demonstrate that in experienced yoga practitioners, brain GABA levels increase after a session of yoga. This suggests that the practice of yoga should be explored as a treatment for disorders with low GABA levels such as depression and anxiety disorders. Future studies should compare yoga to other forms of exercise to help determine whether yoga or exercise alone can alter GABA levels. 419 INTRODUCTION T he practice of yoga includes postures (asanas), breath- ing methods (pranayama), chanting, and meditation (dhyana). 1,2 As the use of these techniques increases, it is important that possible mechanisms underlying the effects of these practices be elucidated. 3 Yoga has shown promise in improving symptoms associated with depression, anxiety disorders, and epilepsy. 4–10 These disorders are associated with low -aminobutyric acid (GABA) states and are ef- fectively treated with pharmacologic agents that increase the activity of the GABA system. 11–18 We hypothesize that the ability of yoga to decrease symptoms in the same disorders is in part mediated through the GABA system and that such 1 Division of Psychiatry, Boston University School of Medicine, Boston, MA. 2 McLean Hospital, Belmont, MA. 3 Department of Psychiatry, Harvard Medical School, Boston, MA. 4 Department of Biostatistics, Boston University School of Public Health, Boston, MA. 5 Boston V.A. Healthcare System, Boston, MA.