Effects of yoga on the autonomic nervous system, gamma-aminobutyric-acid, and allostasis in epilepsy, depression, and post-traumatic stress disorder

Department of Psychiatry, Boston University School of Medicine, Boston, MA 02118, USA.
Medical Hypotheses (Impact Factor: 1.07). 02/2012; 78(5):571-9. DOI: 10.1016/j.mehy.2012.01.021
Source: PubMed


A theory is proposed to explain the benefits of yoga practices in diverse, frequently comorbid medical conditions based on the concept that yoga practices reduce allostatic load in stress response systems such that optimal homeostasis is restored. It is hypothesized that stress induces (1) imbalance of the autonomic nervous system (ANS) with decreased parasympathetic nervous system (PNS) and increased sympathetic nervous system (SNS) activity, (2) underactivity of the gamma amino-butyric acid (GABA) system, the primary inhibitory neurotransmitter system, and (3) increased allostatic load. It is further hypothesized that yoga-based practices (4) correct underactivity of the PNS and GABA systems in part through stimulation of the vagus nerves, the main peripheral pathway of the PNS, and (5) reduce allostatic load. Depression, epilepsy, post traumatic stress disorder (PTSD), and chronic pain exemplify medical conditions that are exacerbated by stress, have low heart rate variability (HRV) and low GABAergic activity, respond to pharmacologic agents that increase activity of the GABA system, and show symptom improvement in response to yoga-based interventions. The observation that treatment resistant cases of epilepsy and depression respond to vagal nerve stimulation corroborates the need to correct PNS underactivity as part of a successful treatment plan in some cases. According to the proposed theory, the decreased PNS and GABAergic activity that underlies stress-related disorders can be corrected by yoga practices resulting in amelioration of disease symptoms. This has far-reaching implications for the integration of yoga-based practices in the treatment of a broad array of disorders exacerbated by stress.

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    • "Also associated with decreased PNS activity would be low levels of gamma amino-butyric acid (GABA). GABA is the primary inhibitory neurotransmitter that helps to lower anxiety (Streeter et al., 2012). Streeter et al. hypothesized that yoga could activate the PNS and increase levels of GABA by stimulating the vagus nerve, which is the primary pathway of the PNS. "
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    DESCRIPTION: Research studies have evidenced the efficacy of prayer to promote patient well-being. Those same studies evidenced an absence of consensus on the definition of prayer. The studies defined prayer as a religious practice, a spiritual practice and a cultural practice. That difficulty to commonly define prayer is also associated with an absence of consensus among health care researchers on the definitions of spirituality and religion. Also absent among health care researchers are hypothetical biological mechanisms to explain how prayer promotes patient well-being. Possible biological mechanisms may include that prayer elicits the relaxation response, thus promoting psychological and physiological benefits, and that prayer may activate the parasympathetic nervous system and increase levels of the neurotransmitter gamma amino-butyric acid (GABA), both of which reduce anxiety. Keywords: prayer, spirituality, religion, well-being
    • "However, very little is known about possible mechanisms by which yoga may reduce symptoms of PTSD. Most of the studies that have examined yoga as an intervention for PTSD or other psychological disorders have focused on possible biological mechanisms through which it may exert its effect (Streeter et al., 2012; Telles et al., 2010; van der Kolk, 2006); only one investigation measured the effects of yoga on mindfulness (Shelov et al., 2009). Shelov and colleagues found that overall trait mindfulness as well as scores on three of four mindfulness subscales increased significantly after an 8-week yoga intervention. "
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    ABSTRACT: Objective This study explored possible mechanisms through which symptoms of posttraumatic stress disorder (PTSD) were reduced in a randomized controlled trial comparing the effect of a yoga intervention with an assessment control.Method We examined whether changes in psychological flexibility, mindfulness, and emotion regulation strategies (expressive suppression and reappraisal) were associated with posttreatment PTSD symptoms for 38 women with Diagnostic and Statistical Manual of Mental Disorders Fourth Edition full or subthreshold PTSD.ResultsHierarchical linear regression models revealed that expressive suppression significantly decreased for the yoga group relative to the assessment control. Psychological flexibility increased significantly for the control but not yoga group. However, increases in psychological flexibility were associated with decreases in PTSD symptoms for the yoga but not control group.Conclusion Preliminary findings suggest that yoga may reduce expressive suppression and may improve PTSD symptoms by increasing psychological flexibility. More research is needed to replicate and extend these findings.
    Journal of Clinical Psychology 12/2014; 70(12). DOI:10.1002/jclp.22104 · 2.12 Impact Factor
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    • "Specifically, RSA is a cardiorespiratory phenomenon that indexes the influence of respiratory frequency and depth of ventilation (i.e., tidal volume) on vagal control of heart rate (HR); whereas, HRV refers to the peak-to-peak variability between successive beats (Grossman and Taylor, 2007). Yoga practice may facilitate high vagal tone (Streeter et al., 2012), which is associated with greater behavioral flexibility in a changing environment and can manifest in decreases in low-frequency HRV, increases in high-frequency HRV, and increased RSA. Vagal tone refers to the activity of the vagus nerve, and its ability to convey afferent (sensory) information about the state of the body's organs to the central nervous system. "
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    ABSTRACT: Research suggesting the beneficial effects of yoga on myriad aspects of psychological health has proliferated in recent years, yet there is currently no overarching framework by which to understand yoga's potential beneficial effects. Here we provide a theoretical framework and systems-based network model of yoga that focuses on integration of top-down and bottom-up forms of self-regulation. We begin by contextualizing yoga in historical and contemporary settings, and then detail how specific components of yoga practice may affect cognitive, emotional, behavioral, and autonomic output under stress through an emphasis on interoception and bottom-up input, resulting in physical and psychological health. The model describes yoga practice as a comprehensive skillset of synergistic process tools that facilitate bidirectional feedback and integration between high- and low-level brain networks, and afferent and re-afferent input from interoceptive processes (somatosensory, viscerosensory, chemosensory). From a predictive coding perspective we propose a shift to perceptual inference for stress modulation and optimal self-regulation. We describe how the processes that sub-serve self-regulation become more automatized and efficient over time and practice, requiring less effort to initiate when necessary and terminate more rapidly when no longer needed. To support our proposed model, we present the available evidence for yoga affecting self-regulatory pathways, integrating existing constructs from behavior theory and cognitive neuroscience with emerging yoga and meditation research. This paper is intended to guide future basic and clinical research, specifically targeting areas of development in the treatment of stress-mediated psychological disorders.
    Frontiers in Human Neuroscience 09/2014; 8:770. DOI:10.3389/fnhum.2014.00770 · 2.99 Impact Factor
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