A recent study found tentative evidence to suggest that yoga exerts its mood-boosting effect by increasing GABA activity among individuals with depression. The study, published in the Journal of Alternative and Complementary Medicine, further suggests that yoga’s beneficial effects on mood are time-limited.
While medication can be highly effective in reducing symptoms of major depressive disorder (MDD), many individuals do not reach remission without additional treatment. Interestingly, yoga interventions have shown promise in reducing depressive symptoms, although it is not clear why.
“Integrative medicine includes consideration of the mind-body interface. Yoga can be used to address many form of illness especially those due to Life Style Choices,” said study author Chris C. Streeter, an associate professor of psychiatry and neurology at the Boston University School of Medicine.
“Many form of western medicine help reduce symptoms but to do completely return people to wellness, the addition of yoga to a treatment regime can increase wellness/decrease symptoms.”
Streeter and her colleagues set out to explore the idea that a yoga intervention increases mood through its effect on an amino acid neurotransmitter called gamma-aminobutyric acid (GABA). The researchers were motivated by findings linking the neurotransmitter to depression.
Specifically, insufficiency in the GABA system has been linked to depressive symptoms, and individuals with MDD have been found to have low GABA levels. On the other hand, yoga interventions have been purported to increase GABA activity.
Streeter and team recruited 32 adults with MDD for a 12-week yoga intervention. Patients were assigned to either a high-dose intervention of three yoga sessions a week or a low-dose intervention of two yoga sessions a week. The yoga sessions included 60 minutes of Iyengar yoga, 10 minutes of relaxation, 20 minutes of breathing practice, and homework exercises.
Throughout the study, the patients underwent magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) scans before the 12-week intervention and following the intervention. At the end of the intervention, all participants took part in an additional 90-minute yoga session and then a third and final brain scan.
The researchers found that the overall direction of the data when considering all participants, pointed to increases in GABA levels between the first and last scans, and the second and third scans. However, there were no differences between the high-dose yoga and low-dose yoga groups.
The findings provide evidence that “yoga is a low cost, low side effect means of improving mood and decreasing anxiety,” Streeter told PsyPost.
The researchers did find that the number of days since a subject’s latest yoga class appeared to be important, perhaps more so than the amount of yoga practice. Specifically, those who showed increased GABA levels at Scan 2 compared to Scan 1, had an average of 3.93 days since their last yoga session. Those whose GABA levels did not go up had an average of 7.83 days since their last yoga session.
“It is probable that the effects of yoga sessions, like pharmacologic treatments, are time limited,” the researchers remark. “The yoga tradition advocates daily practice. The increase in GABA levels seen after a yoga intervention was observed after an average of 4 days, but no longer observed after an average of 8 days.”
The participants had also completed assessments of depressive symptoms at various timepoints. The researchers found that subjects’ GABA levels were not significantly linked to their depressive symptoms. However, changes in depressive symptoms were inversely tied to GABA levels among the high-dose group. As the authors say, this means that depressive symptoms dropped as GABA levels rose.
With a very small sample size, the authors express that their findings are encouraging yet tentative, and future studies should explore the topic among a larger sample.
“The use of yoga for depression needs to be compared to antidepressants in a randomized controlled trial and in combination with anti-depressants,” Streeter said.
Still, the findings suggest that the GABA system may be a mechanism through which yoga improves mood, and practicing yoga at least one time a week may be the key to seeing these benefits.
“There are no magic bullets or pills that completely treat depression or anxiety — yoga is another tool available,” Streeter added. “Many stress-related disorders are associated with an imbalance in the autonomic nervous system with too much sympathetic (fight or flight) and to little parasympathetic (rest, renewal and social engagement). Yoga helps to correct this imbalance.”
The study, “Thalamic Gamma Aminobutyric Acid Level Changes in Major Depressive Disorder After a 12-Week Iyengar Yoga and Coherent Breathing Intervention”, was authored by Chris C. Streeter, Patricia L. Gerbarg, Richard P. Brown, Tammy M. Scott, Greylin H. Nielsen, Liz Owen, Osamu Sakai, Jennifer T. Sneider, Maren B. Nyer, and Marisa M. Silveri.
