Let's Play Therapy Institute

April 7, 2023

Polyvagal theory (PVT) is a widely taught model in the mental health community and for many years I shared my knowledge of the theory with play therapists through my trainings. It wasn’t until I attended a medical conference last year that I began to question the foundation and science behind the theory. As my esteemed colleagues in mental health and in the medical field began challenging me on key biological concepts, I came to discover that Polyvagal theory is indeed not an accepted model in neuroscience. As you can imagine, I was confused and went looking for more answers. I reached out to physicians and read through scientific papers to gain a better understanding of the controversy surrounding this topic. 

These are the key takeaways that I gathered from my conversations and readings of scientific papers:

Parts of PVT comes from already established science such as: our body’s threat detection system and how that inhibits social engagement, and the mechanism of our sympathetic and parasympathetic nervous systems working together to handle stress and threat---all of that was already established by science and actually does have definite application in therapy. 

The neurophysiological mechanisms that Dr. Porges posits, however, are not  supported by the neuroscience community. PVT is about the two parts of the vagus nerve and their relationship with each other. PVT is based on the idea that one of them is evolutionarily newer and does different things than the evolutionary older one does. However, there is no scientific evidence to support that. There is also this idea in PVT that that the newer one provides connections between the heart and the face but again, according to the research, the vagus nerve has little to do with control of the face (there is actually more evidence of the connection between the amygdala and the face than there is between the vagus nerve and the face).

Other criticisms include the issue with phylogenetics, evolutionary assumptions as well as respiratory sinus arrythmia and the way that Dr. Porges talks about the role of the vagus nerve--all are areas not supported by neuroscience. I have read again and again that Dr. Porges oversimplifies and overgeneralizes the role of the vagus nerve.

Mental health clinicians who believe that PVT is the truth more than likely do not understand the details of why it is not scientifically supported because the research can be difficult to understand. But it is extremely important to note that there are very reasonable objections to it. And as health care providers, we have a duty to uphold the highest standards of client care and it is incumbent on us to think critically and engage in these conversations to deepen our understanding of the complexities of the human brain and behavior. 

It was difficult for me to detach myself from PVT and believe me when I say I get the cognitive dissonance! But again, part of good, sound, ethical work is keeping up with the research.

The Lunch n’ Learn (Video Recording Below):

I invited medical expert Dr. Gian Ramos-Monserrate, MD to lead a Lunch n’ Learn and answer our most pressing questions when it came to understanding the criticisms surrounding Polyvagal Theory. The recording of that conversation is included in this blog post below.

In my overexcitement, I forgot to hit the record button during the first 10 minutes of the Lunch n’ Learn. I have included the attendee question and Dr. Ramos-Monserrate’s answer during that 10 minutes below along with resources and references at the end of this post:

Question: “The way I have understood and use this conceptualization is that this 'ladder' is more of a state of activation within the nervous system, including the vagus nerve, not necessarily different distinct nerves. Is this way of communicating and using this information supported by neurobiology?”

Dr. Ramos-Monserrate, MD: The problem with the ladder is that it establishes a hierarchy in which one goes from Dorsal Vagus, to Sympathetic Nervous System, to Ventral Vagal responses.  The very terms, “Dorsal Vagal” and “Ventral Vagal” are important because they denote anatomical distinctions.  While they are two branches of the vagus nerve, one is supposed to be related to “good” things like connection, warmth and safety.  Whilst the other one is related to “bad” things like shutting down, breaking down, fainting.  The current scientific evidence on this distinction is very lacking.  To be more precise, there is very little evidence that the vagus nerve divides itself this way or that the vagus nerve has branches that are responsible for exactly the functions of the ventral part (connection).  

In Neuroanatomy/Physiology one of the ways we generate knowledge as to what certain nerves do is through injury.  When we know that a particular nerve has been injured (we know this by case reports) we observe what the effects are in that person’s behavior.  But there are yet to be case reports that show how an injured vagus nerve, or a vagotomy (surgical intentional injury of the vagus nerve for therapeutic purposes) might result in a reduction in the social engagement aspects of Polyvagal theory. Polyvagal theory is hardly taught in medical settings, I think partly because the model, which is characteristically very medical in its language, actually doesn’t reflect current medical knowledge.

Video of the Lunch n' Learn Below: