Randomized controlled trial of bikram yoga and aerobic exercise for depression in women: Efficacy and stress-based mechanisms

Background:
The current study presents a randomized controlled 8-week trial of Bikram yoga, aerobic exercise, and waitlist for depression. Bikram yoga was chosen specifically for its standardized nature. Further, we examined changes in three stress-related constructs-perceived stress, rumination, and mindfulness-as mediators of antidepressant effects.

Method:
Fifty-three women (age 18-65; 74% White) with a unipolar depressive disorder were randomly assigned to one of the three conditions. Response was defined as >50% reduction on the Hamilton Rating Scale for Depression (HAM-D). Remission was defined as no longer meeting criteria for depression and a HAM-D ≤ 7. Self-reported perceived stress, rumination, and mindfulness were assessed weekly.

Results:
In the intention-to-treat sample (n = 53), response rates were significantly higher in the Bikram yoga (61.1%; χ2 = 10.48, p = .001) and aerobic exercise (60.0%; χ2 = 10.44, p = .001) conditions relative to waitlist (6.7%). In the completer sample (n = 42), 73.3% (χ2 = 11.41, p = .001) of women in yoga and 80.0% (χ2 = 13.72, p < .001) in exercise achieved response compared to 8.3% in waitlist. Reductions in rumination significantly mediated HAM-D change for both active treatments, and mindful acceptance was a partial mediator in the exercise condition.

Limitations:
The sample was small in size, consisted of women only, and was ethnically homogenous. Inter-rater reliability was not assessed, aerobic exercise was not standardized, and mediators were assessed by self-report.

Conclusions:
Bikram yoga showed descriptively similar efficacy to aerobic exercise and both may work, in part, by helping individuals interrupt negative thinking.

Keywords: Aerobic exercise; Bikram yoga; Depression; Mindfulness; Rumination.

PMID: 33242717 DOI: 10.1016/j.jad.2020.10.067