Effects of yoga on anxiety with low-income mentally ill adults

Previous research shows that yoga is associated with improvements in the overall quality of life of hospital patients (Moadel et al, 2007) including improved emotional well-being and physical outcomes such as sleep quality, mood, and stress (Bower et al, 2005).  Increasingly studies are examining the effects of yoga with multicultural populations (e.g. Moadel et al, 2007), but due to cost and awareness barriers, yoga remains largely inaccessible (and therefore underutilized and understudied) to low-income community populations.  The objective of this paper is to explore the effects of yoga on anxiety in low-income mentally ill adults using a randomized experimental switching replication design.

Participants (N=20) were randomized into two groups: “early start” and “late start” and asked to complete the STAI, a standardized measure of anxiety.  Early start participants (n=9) completed 6 weeks of yoga intervention while late start participants (n=9) received their usual treatment.  After six weeks, all participants completed the same standardized measure and late start participants (n=6) began six weeks of yoga intervention while early start participants (n=6) received treatment as usual. 

Results revealed no statistically significant difference between early and late start participants on pretest anxiety (U = 36.5, z = -.35, p = .72).  Results from Wilcoxon Signed Rank Tests revealed a statistically significant decrease in early group anxiety (z = -2.49, p = .01, with a large effect size (r = .59).  The median score on the anxiety measure decreased from pre-program (Md = 44.57) to post-program (Md = 26) for the early group after participation in the yoga class with no difference for the late group.  Without yoga, anxiety increased between time 2 and time 3 for the early group (z = -2.36, p = .02, with a large effect size (r = .57).  The median score on the anxiety measure increased from time 2 (Md = 30) to time 3 (Md = 51.5).  Anxiety was reduced in the late group that received yoga (z = -1.60, p = .11, with a large effect size (r = .50).  The median score on the anxiety measure decreased from pre-program (Md = 51) to post-program (Md = 44), with the lack of statistical significance attributed to attrition (n=4 in the late group at time 3).

Yoga appears to effectively reduce anxiety in low-income mentally ill adults.  Challenges to be addressed include the availability of and accessibility to yoga practice for vulnerable, underserved, populations.