Yoga for depression? Unimpressive science from impressive institutions

The title of the press-release was impressive: ‘Columbia and Harvard Researchers Find Yoga and Controlled Breathing Reduce Depressive Symptoms’. It certainly awoke my interest and I looked up the original article. Sadly, it also awoke the interest of many journalists, and the study was reported widely – and, as we shall see, mostly wrongly.

According to its authors, the aims of this study were “to assess the effects of an intervention of Iyengar yoga and coherent breathing at five breaths per minute on depressive symptoms and to determine optimal intervention yoga dosing for future studies in individuals with major depressive disorder (MDD)”.

Thirty two subjects were randomized to either the high-dose group (HDG) or low-dose group (LDG) for a 12-week intervention of three or two intervention classes per week, respectively. Eligible subjects were 18–64 years old with MDD, had baseline Beck Depression Inventory-II (BDI-II) scores ≥14, and were either on no antidepressant medications or on a stable dose of antidepressants for ≥3 months. The intervention included 90-min classes plus homework. Outcome measures were BDI-II scores and intervention compliance.

Fifteen HDG and 15 LDG subjects completed the intervention. BDI-II scores at screening and compliance did not differ between groups. BDI-II scores declined significantly from screening (24.6 ± 1.7) to week 12 (6.0 ± 3.8) for the HDG (–18.6 ± 6.6; p < 0.001), and from screening (27.7 ± 2.1) to week 12 (10.1 ± 7.9) in the LDG. There were no significant differences between groups, based on response (i.e., >50% decrease in BDI-II scores; p = 0.65) for the HDG (13/15 subjects) and LDG (11/15 subjects) or remission (i.e., number of subjects with BDI-II scores <14; p = 1.00) for the HDG (14/15 subjects) and LDG (13/15 subjects) after the 12-week intervention, although a greater number of subjects in the HDG had 12-week BDI-II scores ≤10 (p = 0.04).

The authors concluded that this dosing study provides evidence that participation in an intervention composed of Iyengar yoga and coherent breathing is associated with a significant reduction in depressive symptoms for individuals with MDD, both on and off antidepressant medications. The HDG and LDG showed no significant differences in compliance or in rates of response or remission. Although the HDG had significantly more subjects with BDI-II scores ≤10 at week 12, twice weekly classes (plus home practice) may rates of response or remission. Although the HDG, thrice weekly classes (plus home practice) had significantly more subjects with BDI-II scores ≤10 at week 12, the LDG, twice weekly classes (plus home practice) may constitute a less burdensome but still effective way to gain the mood benefits from the intervention. This study supports the use of an Iyengar yoga and coherent breathing intervention as a treatment to alleviate depressive symptoms in MDD.

The authors also warn that this study must be interpreted with caution and point out several limitations:

• the small sample size,
• the lack of an active non-yoga control (both groups received Iyengar yoga plus coherent breathing),
• the supportive group environment and multiple subject interactions with research staff each week could have contributed to the reduction in depressive symptoms,
• the results cannot be generalized to MDD with more acute suicidality or more severe symptoms.

In the press-release, we are told that “The practical findings for this integrative health intervention are that it worked for participants who were both on and off antidepressant medications, and for those time-pressed, the two times per week dose also performed well,” says The Journal of Alternative and Complementary Medicine Editor-in-Chief John Weeks

At the end of the paper, we learn that the authors, Dr. Brown and Dr. Gerbarg, teach and have published Breath∼Body∼Mind©, a technique that uses coherent breathing. Dr. Streeter is certified to teach Breath∼Body∼Mind©. No competing financial interests exist for the remaining authors.

Taking all of these issues into account, my take on this study is different and a little more critical:

• The observed effects might have nothing at all to do with the specific intervention tested.
• The trial was poorly designed.
• The aims of the study are not within reach of its methodology.
• The trial lacked a proper control group.
• It was published in a journal that has no credibility.
• The limitations outlined by the authors are merely the tip of an entire iceberg of fatal flaws.
• The press-release is irresponsibly exaggerated.
• The authors have little incentive to truly test their therapy and seem to use research as a means of promoting their business.