Qigong for the treatment of depressive symptoms: Preliminary evidence of neurobiological mechanisms.

<bold>Objectives: </bold>Qigong has been shown to effectively reduce depressive symptoms in older adults with chronic physical illness. Here, we sought to evaluate the effects of qigong on serotonin, cortisol, and Brain-derived Neurotropic Factors (BDNF) levels and test their roles as potential mediators of the effects of qigong on depressive symptoms.<bold>Methods: </bold>Thirty older adults with chronic physical illness participated in a randomized clinical trial. They were randomly assigned to a qigong group (n = 14) or a control group for cognitive training of executive function and memory (n = 16). The participants provided blood and saliva samples at baseline and post-intervention. Levels of cortisol were measured from the salvia samples, and serotonin and BDNF were measured from the blood samples.<bold>Results: </bold>Consistent with the study findings presented in the primary outcome paper, a significant Group × Time interaction effect emerged on depressive symptoms, explained by greater reductions in the qigong group than the control group. Qigong participants had significantly larger increases in serotonin and BDNF, and decreases in cortisol levels, compared with control group participants. Moreover, treatment-related changes in cortisol levels (but not serotonin or BDNF) fully mediated the beneficial effects of qigong on depressive symptoms.<bold>Conclusion: </bold>The findings provide preliminary evidence that treatment-related changes in cortisol may mediate the benefits of qigong on depressive symptoms. Given the limitation of small sample size of the present study, future studies with larger sample sizes and more extended follow-up assessment are warranted to determine the reliability of these findings. [ABSTRACT FROM AUTHOR]