Tuning with others: The Polivagal Theory and the Psychotherapy Process

Abstract

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The main goal of this work is to present the polyvagal theory as a Bio-behavioral model of the emotional and interpersonal behavior, in order to identify realms of contribution from the theory to the study of psychotherapy regarding the clinical status of the patients, the therapeutical process and change. Review of the neurophysiological model describes a reconceptualization of reciprocal relationships between the autonomous nervous system and emotionality in interpersonal contexts, which allows to distinguish conditions of normal normal/pathological activation of behavioral defensive strategies (fight/escape and immobilization), as well as inhibition by means of the prosocial engagement system. Reviewed research describes evidence in favor of the hypothesis derived from the model, both in regular and clinical population. Prosocial engagement system is of particular clinical interest, as it enables the emergence of reliable interpersonal behavior, which turns out to be a fundamental element for psychotherapy due to its potential diagnosis value, as well as because of its effects on development and consolidation of the therapeutical relations and the beneficial results on the patient. Finally, is possible to identify an emerging set of psychotherapy studies which evaluate the activity of prosocial engagement system, by checking high-frequency heart rate, linked to both the process (for instance, work alliance) and the result (for instance, level of symptoms), thus proving the value to deeply study this interdisciplinary line of research and, finally, include these measurements to the clinical bank of evaluations.

Keywords: Psychotherapy, Autonomous Nervous System, Emotional Regulation, Interpersonal Relationships, Prosocial Behavior.

Introduction

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During the last few years psychotherapy studies have provided an emerging interdisciplinary dialogue that has encouraged creation of models and theories aimed to understand how processes of a biological/emotional/cognitive/interpersonal/social nature, are interconnected in order to account for the patient´s health condition (for instance, his/her psychopathologies), the therapy process (for instance, development of therapeutical relationships) and change (for instance,^{(1; 2)}. In this context, and thanks to  this work the polyvagal theory^{(3, 4)} is introduced as a bio-behavioral model aimed to understand the neurophysiological foundations of emotional/interpersonal behavior, which are processes proven to be critical during the etiopathogenesis of mental diseases⁽⁵⁾, as well as in the success of  clinical evolution⁽⁶⁾. The proposed objectives for this work are:
a) to introduce and discuss the neurophysiological model, developed by the polyvagal theory, in order to understand emotionality linked to social behavior, as an emerging biopsicosocial component and the empirical evidence supporting this proposal;
b) From an interpersonal perspective, analyze three main constructs of psychotherapy dealing with the patient, the therapeutical relationship and the therapeutical change; and
c) Discuss the contributions that polyvagal theory may offer to enrich psychotherapy conceptualization, based on distinctions offered by the theory regarding the reviewed constructs.

The Polyvagal Theory and Interpersonal Coupling, as an Emerging Bio-Behavioral Component
The Polyvagal Theory⁽³⁾ introduces a reconceptualization of reciprocal relationships existing among the autonomous nervous system (ANS), emotional expressions/regulations, and  social behavior, by identifying three evolutionary/hierarchical levels, within ANS. In the first level, we can find the most primitive defensive system of immobilization/freezing, which is neurally associated to the oldest vagal branch arising from the dorsal motor nucleus of the brainstem and innervating the sub diaphragmatic organs, whose fibers are myelinated and are it is preserved by means of the phylogeny of vertebrates (for instance, reptiles). The second defensive system is responsible for mobilization behavior, such as fight or escape, which is a feature of mammals, and its neural correlate corresponds to the sympathetic nervous system. In the third level, we can find the most recent system of “social” engagement, or prosocial vagal system, responsible for the proaffiliative/cooperative interpersonal behavior, whose autonomic origin is associated to the most recent phylogenetical vagal branch whose origin is the ambiguous nucleus of the brainstem, that is present in mammals and especially developed in upper primates and humans.
In functional terms, the hyerarchical organization among these three subsystems means that, before the perception of security associated to a reliable environment, the prosocial vagal system is activated, thus enabling calm and trust scenarios, thus inhibiting  tonic influences of the other two defensive subsystems on the organism^{(3, 4)}. The mechanism by means of which the nervous system permanently monitors the presence of surrounding security, and risk is conceptualized as neuroception, which occurs apart from the conscious perceptual processing, by means of phylogenetically old^{(4; 7)} brain areas. This concept is interesting as it explains how a person may bodily react, getting ready for an activation/inhibition defensive response, while the person is not conscious of the risks at a cognitive level. Likewise, for the prosocial vagal system to be activated, not only a lack of surrounding threats is enough, but also these should be other neuro-perceptible signals of trust and security.
When life conditions are healthy, and there are no mental clinical conditions, or else the person is not exposed to some real threat situations against his/her physical and/or psychological integrity, there is a balance in the activation of these three bio-behavioral subsystems, then the subject may respond before acute stressors with quick/effective defensive responses (for instance, respond before a potential urgency or accident) as the prosocial vagal system is inhibited by the perception or neuroception of a threat, which quickly triggers the defensive systems in order to immediately act by means of immobilization/freezing strategies and behavioral mobilization (for instance, initial immobilization initial associated to the orientation response aimed to identify the nature of the stimulus initially perceived as risky and further response activating fight or escape⁽⁸⁾.
Contrariwise, when there are deficits in proper subordination of  defensive systems  before a context that is not a real or potential risk for a person (for instance, in case of psychoaffective development disturbances or before a traumatic experience), the prosocial vagal system is disabled to consolidate psychophysiological states of calm and security that are necessary to create trust relationships, and the person is exposed to defensive behavior that are inadequate for the non-risky nature of relationships. In this way, the subject may perceive others as someone who is not fully reliable, or else the subject may systematically perceive causes of threat in the relationship, but these are not real, thus the subject gets caught in the possibility to consolidate a close/safe relationship⁽⁴⁾.
The polyvagal theory gave birth to a great deal of research that has tested the predictions of the model by means of various ethereal and clinical populations (for a review see⁽⁹⁾). Operationally, the activity of the prosocial vagal system is quantified by means of a psychophysiological construct known as vagal tone⁽³⁾ derived from the respiratory sinus arrhythmia⁽¹⁰⁾, which is obtained by means of different standardized methods aimed to analyze the frequency of the electrocardiogram. Due to the scope of this article and its main objective to discuss the contribution of the polyvagal theory to the study of psychotherapy in adults. Next, you will find a summary of the evidence regarding this age group.
There is a set of significant evidence stating that, in adults, a higher vagal tone is linked to a more healthy expression of psychological variables, such as regulation of negative emotionality⁽¹¹⁾ and flexibility of emotional expression⁽¹²⁾. A poor vagal modulation is linked to a higher level of social anxiety, defensiveness and a lower behavioral activation⁽¹³⁾ and psychopathologies⁽⁹⁾. Especially in the emotional aspects, the vagal tone has been related with a better capability to modulate  negative emotional states, thus favoring cognitive performance⁽¹⁴⁾ and a higher expression of positive emotionality, such as extraversion, kindness⁽¹⁵⁾, and  compassion⁽¹⁶⁾. Probably these results reflect the degree of strength of self-regulatory emotional capabilities that are necessary to consolidate the experience of positive states, such as happiness and calm. This is finally translated into more satisfactory life experiences⁽¹⁷⁾. In this way, a more robust vagal tone may work as  foundation to deploy strategies oriented to the interpersonal closeness, before activation of negative emotional states, thus favoring search for support from other and a lower level of avoidance⁽¹⁷⁾, a higher general sense of social  connection⁽¹⁸⁾ and better understanding of social/emotional keys and reliability, such as empathy^(19,20).
Considered as a whole, the evidence describes a positive correlation between the vagal tone (and the indicators of this type of activity, such as respiratory sinus arrhythmia) and the regulating capacities of our own emotionality, both for healthy people, as well as for clinical patients⁽²¹⁾. In this way, the use of flexible emotional strategies to regulate negative emotionality favors reliable/friendly/proaffiliative interpersonal approach, which may be considered in the psychotherapeutical work due to the relevance present of emotional work and interpersonal correlation existing between patient and therapist, for the development of a successful process. Next, the main concepts referred to psychotherapy are described.

Interpersonal Aspects in Therapy Process
Research has proved that global results of therapy are explained by various aspects attributable to therapy process and to extra-therapeutical factors. By far, the patient himself/herself is who most contributes to explain the change (30%), followed by the therapeutical relationship (12%), the therapist as a person (7%) and the implemented techniques (8%;⁽²²⁾). Within the aspects considered to start a therapy are interpersonal matters of the patients, which have proved to have a higher relevance, at the beginning of the process (75%⁽²³⁾). The foregoing reflects how relevant for people´s welfare is to have close/quality relationships. The sense of connection with others is one of the best mental predictors of mental health⁽²⁴⁾. From a theoretical standpoint, the Theory of Attachment has been commonly used as an interpretive framework, aimed to understand how relevant close relationships in people´s mental health are. This reveals  the need of closeness and reciprocity with  care persons during childhood and throughout life⁽²⁵⁾. Research has proven that taking care of patients´ attachment forms may be a valuable resource to be considered  during psychotherapy, due to prevalence of  more severe psychopathologies within unsafe attachment forms⁽²⁶⁾. At the same time, it is more difficult to adhere and favorably respond to treatment in this type of patients⁽²⁷⁾.
According to the foregoing, effective therapeutical processes has been reported to be characterized by the perception of a “good relationship” by the patient, from the beginning of the therapy all along the process⁽²⁸⁾. Currently the therapeutical relationship is considered as a common factor for a clinical approach, where both parties –therapist and patient–actively help for a good performance⁽²⁹⁾. However, the attributes a person values in others are different. The patient´s subjective judgment is linked –in a more consistent manner– with  psychotherapy results (for instance⁽²⁹⁾ ). Specifically, patients value warmth, care and emotional involvement of their therapists^{(30, 31)}. This provides a hint about what aspects therapists should manifest and keep in this relationship. In this sense, the therapist´s empathy has been positively reported in order to have a successful therapy, this is a unique contribution to change, beyond specific interventions^{(32; 33)}. Evidence is reported in favor of therapeutical empathy, as an interpersonal tuning mechanism. When the patient
–by means of therapeutical interaction internalizes it– that favors a more functional development in patients  to treat himself/herself and generate safer attachment forms⁽³⁴⁾.
This favorable tuning mode between the patient and the therapist has been investigated regarding the change process. Even though change is  a complex phenomenon investigated in various manners (as a main result of the therapy or specific sessions), recent studies have reported that it happens by means of discrete dyadic change interactions, based on  expression aspects provided by the therapist and the patient (for instance, nonverbal synchronicity second by second⁽³⁵⁾. In this sense, the importance of investigating change, beyond the traditional contents or narrative aspects, due to evolutive/ontogenic primacy that nonverbal components have, such as emotional expressiveness, interpersonal coordination  or  the bottom-up type⁽¹⁾.

Contributions of the Polyvagal Theory to Therapy Processes
The polyvagal theory offers a framework for the complex interactions between our nervous system and social/interpersonal keys of the surrounding environment. This has implications for clinical psychology and psychotherapy. On the one hand, several clinical authors have recently discussed implications of the polyvagal theory in order to better understand trauma onset  in patients⁽³⁶⁾. Long-term stress experiences or those that are extremely dangerous (for instance, mistreatment, abuse, child neglect) have been reported to activate old defensive strategies of mobilization/immobilization, based on the sympathetic system and the dorsal vagal, respectively. As a result, the body becomes vulnerable to remain trapped on the onset of diffused symptomatology having an autonomic origin, or else due to sympathetic hyper arousal , which may be appear as anxiety, anguish, tachycardia, arterial hypertension  or sweating, or else as chronic fatigue, dizziness, numbness, gastrointestinal problems, or low artery pressure, caused by vagal hypo arousal⁽³⁷⁾. The polyvagal theory offers an interpretive framework for evaluation, diagnosis and treatment of these symptoms that are hard to detect by the medical system, because in this way it is easy to understand them as an originally adaptive response, when facing a real threat for survival, from which a state of autonomic deregulation arises. Consequently, (psychological and/or medical) treatment should offer security hints in the therapeutical relationship (physician-patient) in order to facilitate numbed self-regulation skills recovery.
Within this logic, a model of coactivation between the therapist and the patient, named circle of contact, has been proposed, aimed to differentiate two levels of interaction in each part of the relationship (patient and therapist) -the neurobiological and the psychosocial aspect-, whose functioning derive into a virtuous synergic influence when therapeutical relationships are deemed as unsafe⁽³⁸⁾. When the therapist performs an effective exercise on therapeutical conditions, such as authenticity, empathy and unconditional acceptance, the patient´s neuroception mechanism allows deployment of better interpersonal skills, higher verbal/non-verbal emotional expressiveness (for instance, visual contact) and, in this way, to be more open experience the critical stages of the therapy. In this same line,⁽³⁹⁾ the discussion about a specific facilitating aspect of the correlation named as  therapeutical presence, which deals with the  therapist´s skills  to be fully present and involved in the therapy has been discussed. The main hypothesis developed by the authors is that prosocial vagal system acts as a mediating mechanism of security, perceived by therapy patients before any therapeutical presence: the neuroception of all non-verbal keys of presence communication (such as facial expressions, gestures and the prosody of the voice) facilitate deactivation of defensive systems  and activation of the patient´s vagal engagement system which, in turn, favors patient´s willingness to work in the therapy, strengthening of therapeutical relationships and generation of new timely interventions of the therapist taking advantage of the current synergy  with the patient.
On the other hand, within the interventions based on attachment,⁽⁴⁰⁾ the scope of polyvagal theory aimed to favor development of constructive strategies, during therapy completion, by virtue of the attachment generated between patient and therapist has been discussed. Especially, when some insecure attachment forms arise in one or in both parties     –paying attention to defensive signs of stress or discomfort which may arise in the final therapy session– may help to favor a positive/timely end, thus avoiding imbalances caused by deployment of secondary attachment strategies, such as early/late completion of the therapy, in order to avoid discomfort experienced in such moment.
Even though the ideas discussed in these works are hypothesis derived from the polyvagal theory –still to be systematically tested in psychotherapy– there are some recent investigations, whose results -preliminarily- support model predictions. Most of these studies have assessed the correlation between the vagal tone (commonly quantified by means of indicators, such as  heart rate variability  in high frequency or else respiratory sinus arrhythmia) prior to, during and/or after the treatment, linked to symptomatological remission in anxious conditions (for instance, TEPT) and mostly depressive, and by means of various intervention modalities (for instance, cognitive-behavioral therapy, psychodynamic interpersonal therapy, treatment against substances abuse, mindfulness). The findings describe two types of associations between the vagal tone and psychotherapy result:
a) on the one hand, there is a positive predictive correlation between the pre-treatment vagal tone of the patients and decrease of symptoms^{(41; 42; 43; 44)}, although such associations have not always been proved (for instance,⁽⁴⁵⁾ ); and
b) A significant increase of the vagal tone has been reported, before/after the treatment^{(40; 46)}. Additionally, the vagal tone during the therapeutical process within the session has been evaluated in patients, as well as the work communion perceived during those sessions, thus proving a positive correlation between both variables⁽⁴⁷⁾.
Even though the evidence presented has some limitations hindering comparability and generalization of its results (for instance, lack of control on drugs consumption which can affect the cardiac function, small size samples and dissipation of vagal tone retrieval methods), the results allow to enhance the design of future studies that may confirm the role of the prosocial vagal system in symptoms development , its interaction with other specific aspects of the therapy (for instance, therapeutical alliance, therapeutical empathy  or level of emotional processing)  in order to determine how these interact among them and influence the course  and success of the treatment. In order to confirm aspects of the polyvagal theory and contribute to its development and improvement, it is of particular interest to further study the role of the prosocial vagal system in the symptoms onset, in order to promptly identify autonomic-vagal deregulation expressions, in order to devise preventive health interventions. Likewise, due to the mediating function of the prosocial vagal system on how people have to safely/reliably engage at an interpersonal level, it is necessary to further study the role the latter has on development of therapeutical relationship (for instance, work alliance), considering mutual dyadic adjustment between the therapist and the patient. In this sense, future research could include evaluation of the vagal tone in both participants, thus pointing to identify the interrelationships and mutual dependences on the development of sessions and therapy results. On the other hand, even though the research must confirm the positive incidence of the therapy on the expression of prosocial vagal system, it is also important to study the factors, which may influence poor effectiveness of the therapy on the autonomic-vagal function, aimed to differentiate clinical groups and support the design of specific interventions for them. Finally, we must consider execution of follow-up studies, in order to learn about the effects in the medium to long term of the therapy on vagal functioning.

Conclusion

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The polyvagal theory offers a reading framework for interpersonal phenomena at stake, by means of psychotherapy, when highlighting the role peripheral processes have (bottom-up type), depending on the autonomous nervous system in the way how patients interact with bond keys offered by the therapists. In this way, phenomena that currently are widely considered in psychotherapy, such as attachment, emotional expressiveness (for instance, proaffiliative v/s defensive) and prosodic aspects of the language (for instance, voice pitch) may be conceptualized from the adaptive-phylogenetic perspective of the autonomic subsystems the theory offers, which may become a promissory field for interdisciplinary clinical research among disciplines regarding patients, therapeutical relationships and change.

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