Psychobiological mechanisms underlying the mental health benefits of yoga-based interventions : a narrative review

Objectives: A comprehensive understanding of the mechanisms of action is important if yoga-based interventions are to be used in the prevention and/or treatment of mental health symptoms. We, therefore, aimed to examine the evidence base and mechanisms underlying the benefits of yoga-based interventions on mental health, with a focus on psychological, physiological and neurobiological mechanisms. Methods: A narrative review was conducted of scoping reviews, systematic reviews and meta-analysis of yoga-based interventions with a focus on psychological, physiological and neurobiological mechanisms linking yoga-based interventions with mental health. A single author conducted a search of the literature using a number of databases (PubMed, Web of Science, Scopus, Google Scholar). Search terms included but were not limited to "yoga*", "asana*," "psych*", "neuro*", "stress", "autonomic", "mental illness", "mental health", "cytokine" and "endocrine". Results: A total of 22 studies were included in this narrative review. These studies report that yoga-based interventions decrease stress reactivity, influence physiological markers of stress reactivity including changes in blood pressure, heart rate, cortisol or cytokine levels, resulting in overall improved health and well-being, in diverse populations of adults. Yoga-based interventions influence psychological processes involved in the regulation of mood and emotion, including self-compassion, dispositional mindfulness, rumination, meta-cognition, attention and memory. Finally, yoga-based interventions result in structural and functional changes in several brain regions. Conclusions: Yoga-based interventions impact multiple processes of mental health; however, further research should explore the potential interaction between these processes as it is possible that effects may be synergistic rather than in silos.