Carriers of the COMT Met/Met allele have higher degrees of hypnotizability, provided that they have good attentional control: a case of gene-trait interaction

Why religion and spirituality are important in human biological research

The study of human biology includes exploration of all the genetic and environmental influences on human variation and life history, including impacts of sociocultural and physical environments. Religious practice and spirituality may be one of these influences. There are more than 5.8 billion religiously affiliated adults and children, accounting for 84% of the world's 6.9 billion people. Furthermore, 70% of Americans consider themselves spiritual in some way, including 22% who do not consider themselves religious, and the numbers for Europe are lower but proportionally similar. Such a high rate of religious affiliation and spiritual belief suggests that religion and spirituality could be sociocultural influences on human variation, but human biologists have scarcely attended to their impacts, as indicated by the limited numbers of relevant articles in the two flagship human biology journals. In this article, we discuss why human biologists may have overlooked this important force for human variability and highlight foundational work from human biology and other disciplines that can give our colleagues directions forward. We review the impacts of religion and spirituality at population and individual levels and call for human biologists to attend to the many aspects of religion and spirituality that can impact human biology and are much more than simply influences of denominational affiliation.

Redefining hypnosis: A narrative review of theories to move towards an integrative model

Hypnosis is an ancient mind-body intervention that has regained interest with the surge of research in the last decade documenting its clinical validity. Yet, theoretical controversies and misconceptions prevail among theorists, clinicians, and the general public, impeding the understanding, acceptance, replication, and use of hypnosis. Providing adequate information, which dispels misconceptions and promotes more balanced views, is warranted to facilitate the implementation and adoption of hypnosis in clinical and research settings. This review re-examines the conceptualisation of hypnosis throughout history and the theoretical controversies surrounding it while highlighting their meeting points and clinical implications. Despite dichotomies, a broad agreement appears across theoretical approaches regarding hypnotic analgesia effects, key components, and vocabulary. Further, theories highlight key factors of hypnotic responding. For instance, social theories highlight social and contextual variables, whereas state theories highlight biopsychosocial mechanisms and individual factors. Based on theories, the terms hypnotherapy or clinical hypnosis are recommended to refer to the therapeutic use of hypnosis in psychotherapeutic and medical contexts, respectively. This review concludes with a model that integrates various theories and evidence and presents hypnosis as a complex multifaceted intervention encompassing multiple procedures, phenomena, and influencing factors. This review intends to deepen our understanding of hypnosis, and promote its more rapid adoption and adequate implementation in research and clinical contexts, in addition to steering research towards evidence-based hypnotic practice. The review can have important research and clinical implications by contributing to advancing knowledge regarding hypnotic procedures, phenomena, and influencing factors.

Physiological Correlates of Hypnotizability: Hypnotic Behaviour and Prognostic Role in Medicine

Studies in the field of experimental hypnosis highlighted the role of hypnotizability in the physiological variability of the general population. It is associated, in fact, with a few differences which are observable in the ordinary state of consciousness and in the absence of suggestions. The aim of the present scoping review is summarizing them and indicate their relevance to the neural mechanisms of hypnosis and to the prognosis and treatment of a few medical conditions. Individuals with high, medium and low hypnotizability scores display different cerebral functional differences-i.e., functional equivalence between imagery and perception/action, excitability of the motor cortex, interoceptive accuracy-possibly related to brain structural and functional characteristics, and different control of blood supply at peripheral and cerebral level, likely due to different availability of endothelial nitric oxide. These differences are reviewed to support the idea of their participation in hypnotic behaviour and to indicate their prognostic and therapeutic usefulness in a few medical conditions.

Hypnotherapy for agoraphobia-Feasibility and efficacy investigated in a pilot study

A number of case studies describing hypnotherapy in the treatment of anxiety disorder patients have already been published. Only a few randomized controlled trials (RCTs) investigated the efficacy of hypnotherapy but focused mainly on symptoms rather than specific mental disorders. The goal of this study was to investigate whether hypnotherapy (HT) was superior to a waitlist control group (WL) in the reduction of agoraphobia-related symptoms. Further goals were to report the feasibility of hypnotherapy as well as attrition and completion rates and detect (epi-)genetic variables, which might play a role in treatment outcome. This pilot study was based on a monocentric two-armed randomized controlled rater-blind clinical trial that was conducted between 2018 and 2020 with a waitlist control group. A total of 36 patients diagnosed with agoraphobia were randomized to either HT or WL. Patients in HT received individual outpatient treatment with hypnotherapy with 8 to 12 sessions for a period of 3 months. Patients in WL received HT after 3 months. Agoraphobia-related symptoms were assessed at baseline, after the treatment, and 3 months later in both groups with a clinician rating. The primary hypothesis concerning the difference between groups in the individual percentage symptom reduction could be confirmed in the intention-to-treat, not the per-protocol sample. Additionally, we applied repeated-measures analyses of variance and found a higher symptom decrease in HT compared with WL patients in three of the five imputed datasets. The dropout rate was low, and satisfaction with the treatment was high. HT patients experienced a strong symptom reduction after receiving hypnotherapy. WL patients improved slightly during the waiting period. The COMT Val108/158Met genotype had an effect on the agoraphobia-related symptoms as well as on COMT DNA methylation levels. This is the first study to indicate that hypnotherapy performed better than a waitlist control group regarding the reduction in anxiety symptoms in an RCT. Future studies should confirm the efficacy of hypnotherapy and compare the treatment with a standard treatment for anxiety disorders in a larger trial. Future studies should also investigate whether hypnotic susceptibility is associated with COMT Val108/158Met genotype and could predict treatment success for HT.

Clinical trial registration

https://classic.clinicaltrials.gov/ct2/show/NCT03684577, identifier: NCT03684577.

Point-of-Care Testing of Enzyme Polymorphisms for Predicting Hypnotizability and Postoperative Pain

Hypnotizability is a stable trait that moderates the benefit of hypnosis for treating pain, but limited availability of hypnotizability testing deters widespread use of hypnosis. Inexpensive genotyping of four single-nucleotide polymorphisms in the catechol-o-methyltransferase (COMT) gene was performed using giant magnetoresistive biosensors to determine if hypnotizable individuals can be identified for targeted hypnosis referrals. For individuals with the proposed optimal COMT diplotypes, 89.5% score highly on the Hypnotic Induction Profile (odds ratio, 6.12; 95% CI, 1.26-28.75), which identified 40.5% of the treatable population. Mean hypnotizability scores of the optimal group were significantly higher than the total population (P = 0.015; effect size = 0.60), an effect that was present in women (P = 0.0015; effect size = 0.83), but not in men (P = 0.28). In an exploratory cohort, optimal individuals also reported significantly higher postoperative pain scores (P = 0.00030; effect size = 1.93), indicating a greater need for treatment.

Cerebrovascular reactivity during visual stimulation: Does hypnotizability matter?

Hypnotizability is a trait associated with several physiological correlates including cardiovascular control. The present study aimed to investigate the posterior cerebral artery flow velocity (PCAv) in basal closed eyes (B) and during visual stimulation (VS) conditions in med-highs and med-lows. Twenty-four healthy volunteers were submitted to the hypnotic assessment through the Stanford Hypnotic Susceptibility Scale, form A which classified 13 low-to-medium (med-lows) and 10 high-to-medium (med-highs) hypnotizable participants. One subject scoring 6 out of 12 was excluded from the comparisons between groups. Arterial blood pressure, heart rate, and partial pressure of end-tidal CO₂ were monitored during both B and VS conditions. Simultaneously, PCAv was assessed by transcranial Doppler. Cerebrovascular Reactivity (CVR) was computed as a percentage of the PCAv change occurring during VS with respect to B (ΔPCAv). During VS both groups increased their PCAv (mean ± SD: 7.9 ± 5.2 %) significantly with no significant group difference. However, among med-highs, CVR was negatively correlated with hypnotizability scores. Thus, higher hypnotizability may be associated with lower metabolic demand in response to VS only within med-highs hypnotizable participants.

Cerebral Blood Flow in Healthy Subjects with Different Hypnotizability Scores

Hypnotizability is a cognitive trait associated with differences in the brachial artery flow-mediated dilatation of individuals with high hypnotizability (highs) and low hypnotizability scores (lows). The study investigated possible hypnotizability-related cerebrovascular differences. Among 24 healthy volunteers, the Stanford Hypnotic Susceptibility Scale Form A identified 13 medium-to-lows (med-lows), 11 medium-to-highs (med-highs), and 1 medium hypnotizable. Hypnotizability did not influence the significant changes produced by the trail making task (TMT), mental arithmetic task (MAT), hyperventilation (HVT), and rebreathing (RBT) on heart rate (HR), arterial blood pressure (ABP), and partial pressure of end-tidal CO₂ (P_ETCO₂), but moderated the correlations between the changes occurring during tasks with respect to basal conditions (Δ) in ABP and P_ETCO₂ with middle cerebral artery flow velocity (MCAv). In HVT, med-lows exhibited a significant correlation between ΔMCAv and ΔP_ETCO₂, and med-highs showed a significant correlation between ΔABP and ΔMCAv. Cerebrovascular reactivity (CVR) and conductance (ΔCVCi) were significantly correlated with ΔMCAv only in med-lows during HVT and RBT. For the first time, cerebrovascular reactivity related to hypnotizability was investigated, evidencing different correlations among hemodynamic variables in med-highs and med-lows.

Well-Being in Highly Hypnotizable Persons

Both hypnotizability and well-being are relevant to health. This study aimed to investigate whether high hypnotizability was positively associated with well-being and whether the latter was related to the activity of the behavioral inhibition/approach system (BIS/BAS). ANOVA revealed significantly higher scores on the General Well-Being Index (PGWBI) in highly hypnotizable (highs, n = 31) compared with low hypnotizable participants (lows, n = 53), with medium hypnotizable participants (mediums, n = 41) exhibiting intermediate values. This finding was discussed in relation to other hypnotizability-related traits, such as morpho-functional brain characteristics, equivalence between imagery and perception, and interoceptive sensitivity. A secondary finding was a nonsignificant gender difference in scores on the PGWBI. The highs' higher well-being could be considered a favorable prognostic factor for physical and mental health.

Implications on hypnotherapy: Neuroplasticity, epigenetics and pain

We provide a brief review about the significance of hypnosis with respect to applications and physiological processes in hypnotherapy. Our review concludes that hypnosis is a promising method to manage acute and chronic pain. In addition, we discuss indications pointing toward the view that hypnosis can induce changes in neuroplasticity possibly involving epigenetic mechanisms.

The neurochemistry of hypnotic suggestion

A diverse array of studies has been devoted to understanding the neurochemical systems supporting responsiveness to hypnotic suggestions, with implications for experimental and clinical applications of hypnosis. However, this body of research has only rarely been integrated and critically evaluated and the prospects for the reliable pharmacological manipulation of hypnotic suggestibility remain poorly understood. Here we draw on pharmacological, genotyping, neuroimaging, and electrophysiological research to synthesize current knowledge regarding the potential role of multiple widely-studied neurochemicals in response to suggestion. Although we reveal multiple limitations with this body of evidence, we identify converging results implicating different neurochemical systems in response to hypnotic suggestion. We conclude by assessing the extent to which different results align or diverge and outline multiple avenues for future research. Elucidating the neurochemical systems underlying response to suggestion has the potential to significantly advance our understanding of suggestion.

Linear and non linear measures of pupil size as a function of hypnotizability

Higher arousal and cortical excitability have been observed in high hypnotizable individuals (highs) with respect to low hypnotizables (lows), which may be due to differences in the activation of ascending activating systems. The present study investigated the possible hypnotizability-related difference in the cortical noradrenergic tone sustained by the activity of the Locus Coeruleus which is strongly related to pupil size. This was measured during relaxation in three groups of participants—highs (N = 15), lows (N = 15) and medium hypnotizable individuals (mediums, N = 11)—in the time and frequency domains and through the Recurrence Quantification Analysis. ECG and Skin Conductace (SC) were monitored to extract autonomic indices of relaxation (heart interbeats intervals, parasympathetic component of heart rate variability (RMSSD) and tonic SC (MeanTonicSC). Most variables indicated that participants relaxed throughout the session. Pupil features did not show significant differences between highs, mediums and lows, except for the spectral Band Median Frequency which was higher in mediums than in lows and highs at the beginning, but not at the end of the session.Thus, the present findings of pupil size cannot account for the differences in arousal and motor cortex excitability observed between highs and lows in resting conditions.

A Critical Review of Standardized Measures of Hypnotic Suggestibility

The most well-established finding gleaned from decades of experimental hypnosis research is that individuals display marked variability in responsiveness to hypnotic suggestions. Insofar as this variability impacts both treatment outcome in therapeutic applications of hypnosis as well as responsiveness to suggestions in experimental contexts, it is imperative that clinicians and researchers use robust measures of hypnotic suggestibility. The current paper critically evaluates contemporary measures of hypnotic suggestibility. After reviewing the most widely used measures, we identify multiple properties of these instruments that result in the loss of valuable information, including binary scoring and single-trial sampling, and hinder their utility, such as the inclusion of suboptimal suggestion content. The scales are not well-suited for contemporary research questions and have outlived their usefulness. We conclude by outlining ways in which the measurement of hypnotic suggestibility can be advanced.

Sex moderates the association between the COMT Val158Met single-nucleotide polymorphism and disorderliness facet of novelty seeking

Previous studies have shown inconsistent results regarding the effect of the Val¹⁵⁸Met polymorphism of the catechol-O-methyltransferase (COMT) gene on personality and cognition. Here, nonclinical Caucasian university students of Italian origin were administered the Temperament and Character Inventory-Revised, Tellegen Absorption Scale, Differential Attentional Processes Inventory, and Waterloo-Stanford Group Scale of Hypnotic Susceptibility. We found that the COMT Val¹⁵⁸Met polymorphism was significantly associated with the disorderliness facet of novelty seeking (NS4) and that sex was a moderator of this association. Females with the Met/Met genotype showed higher NS4 scores compared to those with the Val/Met and Val/Val genotypes. No significant genotype effect was found for males. Additionally, we failed to find a significant effect of the COMT gene on attention and hypnotic suggestibility measures. These results provide further evidence for a sex-specific influence on the gene-behaviour associations.

Effects of Prehypnotic Instructions on Hypnotizability and Relationships Between Hypnotizability, Absorption, and Empathy

Although hypnotizability exhibits high across-time and across-test consistencies, it is not clear (a) how different preambles to a hypnotic procedure (metasuggestions) influence responsiveness to suggestions and the strength of the association between two hypnotizability scales and (b) how hypnotizability relates to absorption and empathy. In Experiment 1, nonclinical participants (N = 152 women) were administered the Modified Tellegen Absorption Scale (MODTAS), Interpersonal Reactivity Index (IRI), Hypnotic Induction Profile (HIP), and Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). In Experiment 2, nonclinical participants (N = 188; 105 women and 83 men) were administered the MODTAS, IRI, and Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A). The induction scores of the HIP (HIP-IND) and the SHSS:C scores showed a significantly stronger correlation when the HIP was introduced to the participants after hypnosis metasuggestion (HIP-H-IND) than after imagination metasuggestion (HIP-I-IND). Metasuggestion was a moderator of the association between HIP-IND and SHSS:C scores. Participants with low and medium, but not with high, hypnotizability levels on the SHSS:C showed significantly higher scores on the HIP-I-IND than on the HIP-H-IND. The strong correlations between the SHSS:C, HIP-H-IND, and HIP eye-roll (HIP-ER) scores indicate that both the HIP-H-IND and HIP-ER are robust measures of hypnotizability. Absorption and empathy were not significantly associated with hypnotizability. Women were more hypnotizable than men, as assessed by the HGSHS:A. The clinical relevance of metasuggestions, intended to increase responsiveness to suggestions, is discussed as a strategy to improve treatment outcomes.

RESPONDING TO SENSORIMOTOR SUGGESTIONS: From Endothelial Nitric Oxide to the Functional Equivalence Between Imagery and Perception

The reduced cerebellar gray matter (GM) volume observed in highly hypnotizable individuals (highs) is likely due to the excessive release of endothelial nitric oxide in the brain and could account for their behavioral (postural and visuomotor control) and physiological (paradoxical pain control after cerebellar anodal stimulation) characteristics. Reduced cerebellar GM can induce low inhibition of the cerebral cortex, thus stronger functional equivalence (FE) between imagery and perception and greater proneness to respond to sensorimotor suggestions. In fact, stronger FE suggested in highs by behavioral studies has been confirmed by topological data analysis of EEG signals recorded during sensorimotor and imagery tasks. The authors' hypothesis cannot be applied to obstructive suggestions likely sustained by mechanisms related to socio-cognitive factors, i.e., oxytocin availability.

Does hypnotic assessment predict the functional equivalence between motor imagery and action?

Motor imagery is influenced by individual and contextual factors. We investigated whether the psychophysiological trait of hypnotisability modulates its subjective experience and cortical correlates similarly to what was previously shown for head postures mental images. EEG was acquired in 18 high (highs) and 15 low (lows) hypnotizable subjects (Stanford Hypnotic Susceptibility Scale, A). The experimental conditions were: baseline, a complex arm/hand movement, visual (1st person) and kinesthetic imagery of the movement. After each imagery condition, participants scored the vividness and easeness of their performance and their ability to mantain the requested modality of imagery. Subjective reports, chronometric visual/kinesthetic indices, absolute beta and fronto-central midline alpha powers were analyzed. Findings confirmed earlier reports of better kinestetic imagery ability in highs than in lows and better visual than kinesthetic imagery in lows, as well as smaller restructuring of the cortical activity in highs than in lows, during all tasks. Also, they show that hypnotisability accounts for most of the correlations between brain regions for both alpha and beta changes. Thus, imagined and actual movements were less demanding processes in highs at subjective and cortical levels. Finally, hypnotic assessment assists to plan personalized mental training for neuro-rehabilitation and sports and predict their efficacy.

Trauma and anxious attachment influence the relationship between suggestibility and dissociation: a moderated-moderation analysis

INTRODUCTION

Hypnotic suggestibility is elevated in the dissociative disorders but the relationship between dissociative tendencies and suggestibility in the general population seems to be constrained by additional factors. The diathesis-stress (DS) model stipulates that suggestibility interacts with trauma exposure to augment the propensity for dissociative states whereas the dual pathway to suggestibility (DPS) model proposes two developmental routes involving either dissociation preceded by trauma, or a healthy cognitive profile characterised by superior imagination.

METHODS

This study sought to discriminate between these partially competing accounts and further considered the moderating role of anxious attachment. 209 participants completed psychometric measures of dissociative tendencies, trauma, and attachment, and a behavioural measure of suggestibility.

RESULTS

In support of the DS model, trauma moderated the relationship between suggestibility and dissociation and, as predicted by the DPS model, dissociation moderated the relationship between trauma and suggestibility. Anxious attachment additionally moderated both effects. Model comparisons indicated that the DS model consistently provided a superior fit to the data. Further analyses showed that secure attachment independently predicted suggestibility, thereby supporting the non-dissociative pathway in the DPS model.

CONCLUSIONS

These results suggest that high suggestibility confers vulnerability to dissociative states in individuals exposed to trauma and displaying an anxious attachment style.

Psychedelics and hypnosis: Commonalities and therapeutic implications

BACKGROUND

Recent research on psychedelics and hypnosis demonstrates the value of both methods in the treatment of a range of psychopathologies with overlapping applications and neurophenomenological features. The potential of harnessing the power of suggestion to influence the phenomenological response to psychedelics toward more therapeutic action has remained unexplored in recent research and thereby warrants empirical attention.

AIMS

Here we aim to elucidate the phenomenological and neurophysiological similarities and dissimilarities between psychedelic states and hypnosis in order to revisit how contemporary knowledge may inform their conjunct usage in psychotherapy.

METHODS

We review recent advances in phenomenological and neurophysiological research on psychedelics and hypnosis, and we summarize early investigations on the coupling of psychedelics and hypnosis in scientific and therapeutic contexts. Results/outcomes: We highlight commonalities and differences between psychedelics and hypnosis that point to the potential efficacy of combining the two in psychotherapy. We propose multiple research paths for coupling these two phenomena at different stages in the preparation, acute phase and follow-up of psychedelic-assisted psychotherapy in order to prepare, guide and integrate the psychedelic experience with the aim of enhancing therapeutic outcomes.

CONCLUSIONS/INTERPRETATION

Harnessing the power of suggestion to modulate response to psychedelics could enhance their therapeutic efficacy by helping to increase the likelihood of positive responses, including mystical-type experiences.

COMT Genotype and Sensory and Sensorimotor Gating in High and Low Hypnotizable Subjects

We investigated the association between hypnotizability, COMT polymorphism, P50 suppression ratio, and prepulse inhibition of acoustic startle response (ASR) in 21 high (HH) and 19 low (LH) hypnotizable subjects. The frequency of Met/Met carriers of COMT polymorphysm was higher in HH than in LH group (33.3% versus 10.6%, p = .049). Increased ASR amplitude and latency and decreased prepulse inhibition at 120 ms lead interval were found in the HH compared to the LH group. The effect of COMT genotype on prepulse inhibition was observed in LH group only. No between-group differences in P50 measures were found. The obtained results suppose the participation of dopamine system in mechanisms of hypnotizability and different allocation of attentional resources in HH and LH subjects.

Dopaminergic and Serotonergic Genotypes and the Subjective Experiences of Hypnosis

Hypnotizability is related to the Val¹⁵⁸Met polymorphism of the COMT gene. The authors' aim was to find associations between candidate genes and subjective dimensions of hypnosis; 136 subjects participated in hypnosis and noninvasive DNA sampling. The phenomenological dimensions were tapped by the Archaic Involvement Measure (AIM), the Phenomenology of Consciousness Inventory (PCI), and the Dyadic Interactional Harmony Questionnaire (DIH). The main results were that the "Need of dependence" subscale of AIM was associated with the COMT genotypes. The GG subgroup showed higher scores, whereas AA had below average scores on the majority of the subjective measures. An association between the 5-HTTLPR polymorphism and the intimacy scores on the DIH was also evident. The effects are discussed in the social-psychobiological model of hypnosis.