Yoga practice consisting of physical postures and breathing techniques can be helpful in improving symptoms of depression and anxiety in patients with major depressive disorder (MDD), new research suggests.
Investigators studied the impact of Iyengar yoga postures and coherent breathing by randomly assigning 32 adults with MDD to either a high-dose group (HDG) or a low-dose group (LDG), based on the frequency of classes and homework sessions, over a 12-week period.
Both groups experienced improvement in symptoms of depression and anxiety as well as increased feelings of positivity.
“Yoga and regulated breathing practices have been used for thousands of years in diverse cultures to manage stress, anxiety, depression, pain, and many other conditions,” study coauthor Patricia L. Gerbarg, MD, an assistant professor in psychiatry at New York Medical College in Valhalla, told Medscape Medical News.
“Clinicians should seriously consider including mind-body practices such as yoga and coherent breathing in their treatment recommendations for patients with depressive symptoms,” she added.
The study was published online November 13 in the Journal of Psychiatric Practice.Dosing Unclear
Although a growing evidence base supports the role of yoga as an “effective treatment for MDD,” few (if any) published studies evaluate its optimal “dosing,” the authors write.
The current study aimed to “assess the effects of an intervention combining Iyengar yoga and coherent breathing on psychological function in subjects with MDD and determine the optimal dose of the intervention for future randomized controlled trials.”
Participants were randomly assigned to either HDG (n = 15), which involved three 90-minute yoga classes and four 30-minute homework sessions per week, or to LDG (n = 15), which consisted of two 90-minute yoga classes and three 30-minute homework sessions per week.
Participants ranged in age from 18 to 65 years (mean age 38.4 ± 15.1 years in the HDG group and 34.7 ± 10.4 years in the LDG group). Most participants in both groups were female (87% and 80%, respectively) and white (67% and 87%, respectively).
There were no differences in mean age, gender distribution, educational level, or race/ethnicity between the two groups and no statistically significant differences in any measures at baseline.
Participants completed an array of psychological questionnaires and mood scales, including the Patient Health Questionnaire (PHQ-9) and the Spielberg State-Trait Anxiety Inventory-State (STAI-State) at baseline and at weeks 4, 8, and 12.
The yoga practice exposure (ie, the combined time in class plus homework completed) was a mean of 86.7 hours in the LDG group and 122.8 hours in the HDG group.Acute and Cumulative Benefits
Participants in both groups experienced significant improvements in all outcome measures, including acute as well as cumulative benefits.
Although HDG participants showed greater improvement in all scales, the between-group differences were not statistically significant, “possibly due to lack of power because of the small sample size,” the authors suggest.
PHQ scores decreased by 36.8% from baseline to week 12, with each additional cumulative yoga-hour associated with a significant decrease of 0.044 points (β = −0.044; SE = 0.005; P < .0001), “indicating a reduction in depressive symptoms,” the authors report.
There was, however, no significant difference between the LDG and the HDG groups (β = −0.042; SE = 0.013; P = .002 and β = −0.045; SE = .006; P < .0001, respectively).
Improvements were also seen in symptoms of anxiety, with each additional cumulative hour spent in yoga practice associated with a significant decrease in anxiety severity by approximately 0.105 points on the STAI-State scale [overall, β = −0.105; SE = 0.020; P < 0.0001).
Increasing the cumulative amount of time spent on yoga practice led to significant improvements in increased positive engagement, revitalization, and tranquillity as well as decreased physical exhaustion.
“The time commitment for yoga practice needs to be weighed against the benefits when designing yoga interventions,” the authors note.GABA Connection
Gerbarg cited research suggesting that yoga and coherent breathing may “activate afferent vagal parasympathetic pathways that lead to increasingγ-aminobutyric acid (GABA) levels” — a mechanism she called the “vagal-GABA theory.”
For example, in a previous study, Gerbarg and colleagues used magnetic resonance spectroscopy (MRS) brain imaging to compare levels of GABA in healthy controls vs individuals with MDD who were receiving a 12-week yoga intervention consisting of physical postures and coherent breathing.
At baseline, those with MDD had lower levels of GABA compared with their healthy control counterparts. However, after the intervention, their depressive and anxiety symptoms improved and their GABA levels were similar to those of healthy controls.
“The finding that yoga and coherent breathing can increase the activity of the neurotransmitter GABA opens the door for using these methods in the treatment of anxiety disorders, substance abuse, and posttraumatic stress disorder, [since] GABA is necessary to inhibit or calm the overactivity of the amygdala that occurs in anxiety disorders, substance abuse, and PTSD,” Gerbarg said.
A recent editorial by Varambally et al, published in the British Journal of Psychiatry, examines the evidence base for the use of yoga as a therapeutic intervention in psychiatric disorders, suggesting that yoga may be evolving “from fad to evidence-based intervention.”
The authors present evidence supporting the role of yoga in improving symptoms of depression and suicidal ideation, as well as improving negative symptoms, quality of life, and social cognition in individuals with schizophrenia.
They note that an “emerging evidence base” points to beneficial biomarker changes resulting from yoga practice, including enhancement of GABAergic neurotransmission, modulation of the hypothalamic–pituitary–adrenal (HPA) axis, and increased serotonin levels in the brain.Outcome Enhancer?
Commenting on the study for Medscape Medical News, Patricia Anne Kinser, PhD, WHNP-BC, RN, an associate professor at VCU School of Nursing in Richmond, said research into nonpharmacologic therapies for depression “is greatly needed” and that mind-body therapies, such as yoga, “have great potential for enhancing outcomes in individuals experiencing depressive symptoms.”
In particular, it is “highly relevant to evaluate ideal dosing of interventions [because] in order to create evidence-based recommendations, clinicians and researchers need to know what the ‘minimum dose’ might be of an intervention,” said Kinser, who was not involved with the study.
“I personally don’t believe that the dosing of the two groups were disparate enough to detect differences between them,” she added. “This study does not compare findings with a comparison group — eg, an active control group — and the sample size was quite small, so the findings do not significantly advance the field.”
For this reason, “more research must be conducted in this area before we can make evidence-based recommendations to our patients about the ideal dosing of a yoga intervention,” she said.
Kinser noted that her own previous research “has suggested that even inconsistent practice of yoga-based interventions can have sustained impact over time.”
The study authors acknowledge that the small sample size “limits the ability to determine between-group differences and to generalize to larger populations.”