Increasing evidence indicates that regular practice of yoga is effective in reducing stress and its effects and even appears to relieve the symptoms of clinical depression.
Yoga is a traditional practice originating in India designed to help the practitioner achieve and maintain both good physical and mental health, as well as fostering spritual enlightenment. The practice incorporates elements of physical exercise, meditation and breathing regulation.
This ancient Eastern discipline continues to gain in popularity in the West for its wide-ranging benefits and medical researchers are taking an increasing interest in its potential to contribute to the prevention and treatment of a diverse collection of physical and mental ailments.
Depression is one disorder in which scientists are keen to investigate the effects of the regular practice of yoga. A review article published in the Journal of Psychiatric Practice in January of this year analysed the results of five clinical trials using yoga as an intervention for depression and three trials in which yoga was evaluated in individuals without a clinical diagnosis of depression but who reported elevated symptoms of depression. The review concluded that the evidence presented by these clinical trials was overwhelmingly favourable but must be considered preliminary due to concerns about the methods of study used.
The authors of the review go on to make the case for more robust study of the efficacy of yoga in depressed individuals. They make three main points: "First, current strategies for treating depression are not sufficient for many individuals, and patients have several concerns about existing treatments. Yoga may be an attractive alternative to or a good way to augment current depression treatment strategies. Second, aspects of yogaincluding mindfulness promotion and exerciseare thought to be 'active ingredients' of other successful treatments for depression. Third, there are plausible biological, psychological, and behavioral mechanisms by which yoga may have an impact on depression."
One such mechanism which has been the subject of a number of studies involves elevated production of the calming neurotransmitter gamma-aminobutyric acid (GABA) when depressed patients practice yoga. GABA is often referred to as the body's natural tranquilizer since it prevents the firing of neurons and thus helps to prevent the overstimulation of the brain and nervous system that results from stress and contributes to the development of depression.
In 2007 researchers from Boston University School of Medicine and Harvard Medical School looked at changes in levels of GABA in the brains of experienced yoga practitioners following 60 minutes of yoga practice compared to levels of GABA in the brains of control subjects who completed a 60 minute reading session. The study revealed GABA increased by 27 per cent in the yoga practitioners while it did not change in the reading group. The researchers concluded that yoga could potentially help in conditions that involve abnormally low levels of GABA, including depression and anxiety.
That yoga protects the brain from depression by increasing release of GABA in the brain was confirmed last month, again through a study conducted by Boston University School of Medicine scientists. This time they found three sessions of yoga per week was enough to boost depressed participants' levels of GABA and this correlated with reduced symptoms. A control group who spent the same amount of time walking also improved but to a lesser degree and the association with GABA levels was less distinct. Assistant professor of psychiatry and study author Chris Streeter commented: "People who have disorders like depression and anxiety can definitely benefit from yoga, because it returns [GABA] levels to the normal range."
The current evidence then suggests yoga can be a valuable component of successful treatment protocols for depressive and mood disorders, not least because it is essentially free and lacks the side-effects that dog antidepressant medication use.
Uebelacker LA Epstein-Lubow G Gaudiano BA Tremont G Battle CL Miller IW (2010) Hatha yoga for depression: critical review of the evidence for efficacy, plausible mechanisms of action, and directions for future research Journal of Psychiatric Practice 16(1):22-33
Streeter CC Whitfield TH Owen L Rein T Karri SK Yakhkind A Perlmutter R Prescot A Renshaw PF Ciraulo DA Jensen JE (2010) Effects of Yoga Versus Walking on Mood, Anxiety, and Brain GABA Levels: A Randomized Controlled MRS Study Journal of Alternative and Complementary Medicine> 2010 Aug 19 [Epub ahead of print]
Streeter CC Jensen JE Perlmutter RM Cabral HJ Tian H Terhune DB Ciraulo DA Renshaw PF (2007) Yoga Asana sessions increase brain GABA levels: a pilot study Journal of Alternative and Complementary Medicine 13(4):419-26