By Sat Bir Singh Khalsa, Ph.D.
Depression is a prevalent and debilitating mental health condition that can affect anyone at anytime. Researchers have found that the majority of individuals with major depressive disorder (MDD) report only a 50% decrease in symptoms with the use of antidepressant medication, the standard treatment for depression. MDD significantly affects daily functioning, with 60% of depressed individuals reporting that the condition has a severe or very severe impairment on their daily lives. The chronic nature of depression is that there is most likely a cyclical relationship in the brain mechanisms involved in the regulation of mood and stress responsivity, such that depression may occur because of life stress and life stress may be a result of depression. This suggests that managing stress may break this cycle.
As a common complementary therapy in the United States, yoga may be particularly helpful for depression because it can be adapted to daily mood through integrating practices to enhance physical, emotional, and spiritual health. Most notably, yoga is easily available and can be self-administered. The slow rhythmic breathing practices and meditative/ relaxation practices of yoga are designed to induce a sense of calm, well being, stress tolerance, and mental focus, all of which can be of help for depressed individuals. Stress is one of the major known risk factors for the development of depression. Increased risk of depression can result from life events like divorce, death, or loss of employment, in addition to chronic stresses like illness, lack of social support, and numerous daily stressors. Given yoga’s ability to improve stress coping, yoga has some potential for both preventing and coping with depression and its symptoms.
In understanding how depression works, it is important to examine the brain, in particular the ventromedial (or subgenual) prefrontal cortex (VMPFC). The VMPFC integrates limbic, emotion-related information and translates this into modulation of autonomic and behavior outflow. Also, the VMPFC appears to function as a nodal brain region whereby social and emotional conditions interact with information from the body related to stress and relaxation, and is likely to contribute to mechanisms by which mind-body therapies like yoga can influence mood, social function, as well as autonomic output. Major input to the VMPFC includes projections carrying feedback from the body related to stress and viscerosensory signals. Because yoga encourages mindfulness, positive self-talk, and self-acceptance, which may help increase self-confidence and sense of self, these aspects may engage the VMPFC by encouraging a focus on body movements and the breath. In fact, researchers have shown that the application of mindfulness and meditation over the long-term enhances emotion regulation by reducing emotionally reactivity and this is reflected in actual structural changes in the brain; the amygdala in the limbic system responsible for emotion is actually reduced in size. This, in turn, reduces concentrations of stress-signaling molecules and increases dopamine levels. These effects improve the potential for better control over emotions, mood, and anxiety and for increased relaxation. Further, it is important to point out that practicing yoga does not typically involve ignoring depressive or anxious thoughts, but rather focuses more on non-judgmental acceptance of these thoughts, resulting in positive effects for depressed individuals.
The use of yoga as both an alternative and an adjunct to standard treatment for depression is reflected by the increasing number of studies assessing yoga as a treatment for depression. The quantity of this research has reached the point where there are now well over a dozen published systematic reviews and meta-analyses of the research on mind-body medicine approaches for depression including 4 review papers specific to yoga for depression published since 2005. An early 2005 review identified and described 5 clinical randomized controlled trials suggesting some benefit of yoga. In 2010, a review paper by researchers at Brown University School of Medicine reported on 8 clinical trials, and in addition to supporting yoga’s potential efficacy, also described the potential mechanisms involved. More recently in 2013, a more rigorous review, a so-called meta-analysis that applies statistical analytic techniques to published research results, was published by a group led by German yoga researcher Holger Cramer. This study found 27 clinical trials and examined the 12 of these that were randomized controlled trials that involved a total of 619 patients/research participants. They concluded that yoga is efficacious as compared with usual/standard clinical care, and somewhat better than relaxation or aerobic exercise, and benefits were shown for both patients with depressive disorders and in individuals with elevated levels of depression.
Interestingly, they also noted that the more meditation-based forms of yoga appeared to be more beneficial than the more exercise-focused yoga styles. However, a more recent informal review paper in 2014 reported on six studies employing yoga styles that had physical practices/asanas as a core component, and concluded that there were positive benefits. Not surprisingly, as with any novel field of research, there are limitations on the quality of the yoga for depression clinical research literature and therefore of what can be claimed. For example, there are few studies that solely investigate the effects of yoga for depression, the study sample sizes are small in many studies and the generalizability of benefits noted in participants who demonstrate the motivation to participate and comply in studies of yoga may be questionable, the severity of depression is not known across studies, and although adverse effects have not been reported in these studies, details of how the assessments have been completed are lacking. Nevertheless, the research literature is encouraging enough to support publication of a brief 2014 Journal of Family Practice paper (that reaches more practicing clinicians) that summarized these published reviews concluding that “Yes, yoga can reduce symptoms of anxiety and depression…”.
An advantageous factor in the application of yoga as a treatment for depression may be that yoga is safe, cost-effective, and can be used as an adjunct to medication. Increasingly, health care providers are encouraging their clients and patients to use self-management approaches for the treatment and management of chronic diseases such as depression. The fact that yoga is versatile, allows for personalization, and can be practiced in studios, gyms, outdoors, and at home is ideal for this form of self-care. Mind-body therapies, like yoga, can support pharmacological and psychological therapies by improving stress and emotion regulation and reactivity. Social support, which is an additional benefit of group yoga practice, has proven to have a positive impact on some individual’s mood and coping skills. Thus, the practice of yoga warrants serious consideration as a potentially efficacious strategy that would allow depressed individuals to cope with their depressive symptoms and their consequences. Further rigorous research is warranted to clarify specific mechanisms of yoga’s efficacy for depression and to determine the best practices and application of yoga that yield optimum benefit.
Sat Bir Singh Khalsa, Ph.D. is the KRI Director of Research, Research Director for the Kripalu Center for Yoga & Health, and Assistant Professor of Medicine at Harvard Medical School. He has practiced a Kundalini Yoga lifestyle since 1973 and is a KRI certified Kundalini Yoga instructor. He has conducted research on yoga for insomnia, stress, anxiety disorders, and yoga in public schools, he is editor in chief of the International Journal of Yoga Therapy and The Principles and Practice of Yoga in Health Care and author of the Harvard Medical School ebook Your Brain on Yoga.