Using Polyvagal Theory in Clinical Settings
In last month’s post, I explained the basic concepts of the Polyvagal Theory, a theory proposed by Stephen Porges that describes how the mammalian autonomic nervous system evolved to keep us safe and alive. In short, the Polyvagal Theory states that:
“When challenged, the regulation of the autonomic nervous system sequentially degrades to older circuits as an adaptive attempt to survive.” -Stephen Porges, The Pocket Guide to the Polyvagal Theory, p. 64
This means that when we sense danger, our sympathetic nervous system takes over and we go into fight-or-flight mode. If our fight-or-flight defenses don’t make us feel safe, the sympathetic nervous system can become inhibited as our ancient, reptilian defense mechanisms take over. These defense mechanisms immobilize us and can make us faint.
When people experience chronic stress or trauma, their nervous system can get stuck in fight-or-flight mode or in a state of immobilization. This can result in high blood pressure, elevated levels of stress hormones, anxiety, insomnia, a range of psychological problems including dissociation, avoidance, and the inability to communicate, and physiological issues involving the organs of the body.
The bidirectionality of the vagus nerve is central to Polyvagal Theory. The vagal nerve fibers that control parasympathetic function of the organs and motor function of the mouth, pharynx, and larynx only make up about 20% of the fibers in the vagus nerve. The other 80% of vagal nerve fibers are afferent, meaning that they send sensory information from the organs back to the brain.
So, not only does our brain function affect our organs, but the function of our organs affects our brain. Malfunctioning organs send feedback to the nervous system about their state, and the nervous system may conclude that we are in a state of danger because our organs are not functioning correctly. This can be a vicious cycle from which it is difficult to escape. Polyvagal Theory emphasizes the importance of addressing these physiological issues in order to help people overcome the effects of trauma.