Hypnotizable Individuals Research Articles

Interoception as a function of hypnotizability during rest and a heartbeat counting task.

The hypnotizability-related differences in morpho-functional characteristics of the insula could at least partially account for the differences in interoceptive accuracy (IA) observed between high and low hypnotizable individuals (highs, lows). Our aim was to investigate interoceptive processing in highs, lows, and medium hypnotizable individuals (mediums), who represent most of the population, during a 10-minute open eyes relaxation condition (Part 1) and three repetitions of consecutive 2-minute open eyes, closed eyes, and heartbeat counting conditions, followed by a 2-minute post-counting condition (Part 2). Electrocardiogram and electroencephalogram were recorded in 14 highs, 14 mediums, and 18 lows, classified according to the Stanford Hypnotic Susceptibility Scale: Form A. Heartbeat-evoked cortical potentials (HEP) were extracted throughout the entire session, and IA index was obtained for the heartbeat counting task (HCT). In Part 1, significant hypnotizability-related differences were observed in the right central region in both early and late HEP components, with lows showing positive amplitudes and highs/mediums showing negative amplitudes. In Part 2, the same group differences were limited to the early component. Moreover, in the left frontal regions, only mediums modified their HEP during the counting task with respect to the open/closed eyes conditions, whereas highs displayed HEP differences between counting and post-counting rest. HCT did not show significant group differences. In conclusion, highs and mediums seem to be more similar than mediums and lows regarding HEP, despite the absence of significant differences in HCT. Nonetheless, a negative correlation between hypnotizability scores and HEP amplitudes was observed in the regions showing group differences.

Stanford Hypnosis Integrated with Functional Connectivity-targeted Transcranial Stimulation (SHIFT): a preregistered randomized controlled trial

AbstractHypnotizability, one’s ability to experience cognitive, emotional, behavioral and physical changes in response to suggestions in the context of hypnosis, is a stable neurobehavioral trait associated with improved treatment outcomes from hypnosis-based therapy. Increasing hypnotizability in people who are low-to-medium hypnotizable individuals could improve both the efficacy and effectiveness of therapeutic hypnosis as a clinical intervention. Hypnotizability is associated with dorsolateral prefrontal cortex (DLPFC) functions and connectivity with the salience network, yet there is conflicting evidence as to whether unilateral inhibition of the DLPFC changes hypnotizability. We hypothesized that using personalized neuroimaging-guided targeting to non-invasively stimulate the left DLPFC with transcranial magnetic stimulation (TMS) would temporarily increase hypnotizability. In a preregistered, double-blinded, randomized controlled trial, we recruited a sample of 80 patients with fibromyalgia syndrome, a functional pain disorder for which hypnosis has been a demonstrated beneficial non-pharmacological treatment option. All participants were TMS-naive. Participants were randomly assigned to active or sham continuous theta-burst stimulation over a personalized neuroimaging-derived left-DLPFC target, a technique termed SHIFT (Stanford Hypnosis Integrated with Functional Connectivity-targeted Transcranial Stimulation). We tested our hypothesis using the hypnotic induction profile scores, a standardized measure of hypnotizability. Pre-to-post SHIFT change in the hypnotic induction profile scores was significantly greater in the active versus sham group after 92 s of stimulation (P = 0.046). Only the active SHIFT group showed a significant increase in hypnotizability following stimulation (active: P < 0.001; sham: P = 0.607). As such, modulation of trait hypnotizability is possible in humans using non-invasive neuromodulation. Our findings support a relationship between the inhibition of the left DLPFC and an increase in hypnotizability. Dose–response optimization of spaced SHIFT should be explored to understand the optimal dose–response relationship. ClinicalTrials.gov registration: NCT02969707.

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.

Strategies that reduce Stroop interference.

A remarkable example of reducing Stroop interference is provided by the word blindness post-hypnotic suggestion (a suggestion to see words as meaningless during the Stroop task). This suggestion has been repeatedly demonstrated to halve Stroop interference when it is given to highly hypnotizable people. In order to explore how highly hypnotizable individuals manage to reduce Stroop interference when they respond to the word blindness suggestion, we tested four candidate strategies in two experiments outside of the hypnotic context. A strategy of looking away from the target words and a strategy of visual blurring demonstrated compelling evidence for substantially reducing Stroop interference in both experiments. However, the pattern of results produced by these strategies did not match those of the word blindness suggestion. Crucially, neither looking away nor visual blurring managed to speed up incongruent responses, suggesting that neither of these strategies is the likely underlying mechanism of the word blindness suggestion. Although the current results did not unravel the mystery of the word blindness suggestion, they showed that there are multiple voluntary ways through which participants can dramatically reduce Stroop interference.

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.

Multisensory Integration Is Modulated by Hypnotizability

ABSTRACT This study investigated multisensory integration in 29 medium-to-high (mid-highs) and 24 low-to-medium (mid-lows) hypnotizable individuals, classified according to the Stanford Hypnotic Susceptibility Scale, Form A. Participants completed a simultaneity judgment (SJ) task, where an auditory and a visual stimulus were presented in close proximity to their body in a range of 11 stimulus onset asynchronies. Results show that mid-highs were prone to judge audiovisual stimuli as simultaneous over a wider range of time intervals between sensory stimuli, as expressed by a broader temporal binding window, when the visual stimulus precedes the auditory one. No significant difference was observed for response times. Findings indicate a role of hypnotizability in multisensory integration likely due to the highs’ cerebellar peculiarities and/or sensory modality preference.

Now You See One Letter, Now You See Meaningless Symbols: Perceptual and Semantic Hypnotic Suggestions Reduce Stroop Errors Through Different Neurocognitive Mechanisms.

Compelling literature has suggested the possibility of adopting hypnotic suggestions to override the Stroop interference effect. However, most of these studies mainly reported behavioral data and were conducted on highly hypnotizable individuals. Thus, the question of the neural locus of the effects and their generalizability remains open. In the present study, we used the Stroop task in a within-subject design to test the neurocognitive effects of two hypnotic suggestions: the perceptual request to focus only on the central letter of the words and the semantic request to observe meaningless symbols. Behavioral results indicated that the two types of suggestions did not alter response time (RT), but both favored more accurate performance compared to the control condition. Both types of suggestions increased sensory awareness and reduced discriminative visual attention, but the perceptual request selectively engaged more executive control of the prefrontal cortex (PFC), and the semantic request selectively suppressed the temporal cortex activity devoted to graphemic analysis of the words. The present findings demonstrated that the perceptual and the semantic hypnotic suggestions reduced Stroop errors through common and specific top-down modulations of different neurocognitive processes but left the semantic activation unaltered. Finally, as we also recruited participants with a medium level of hypnotizability, the present data might be considered potentially representative of the majority of the population.

Association of hypnotizability and deep sleep: any role for interoceptive sensibility?

The aim of the study was to investigate the possible association of hypnotizability and deep sleep (N3) duration, and whether the interoceptive sensibility influences this association. This was motivated by the proneness of highly hypnotizable individuals to easily change their psychophysiological state, i.e., from wakefulness to hypnosis and sleep, and by the positive association observed between hypnotizability and interoceptive sensibility. Forty-seven healthy participants previously enrolled in a polysomnographic night sleep study completed the questionnaire for Multidimensional Assessment of Interoceptive Awareness (MAIA) and underwent hypnotic assessment through the Stanford Hypnotic Susceptibility Scale, form A (SHSS,A). Results showed that N3 duration is not linearly correlated with hypnotizability. Controlling for a few MAIA scales did not modify the relation between hypnotizability and deep sleep. A polynomial relation indicates that N3 duration and N3 percentage of the total sleep time increase with hypnotizability in the low-to-medium range of hypnotizability and decrease in the medium-to-high range. In conclusion, hypnotic assessment predicts N3 duration and their association is not modified by interoceptive awareness/sensitivity.

Acute assessment of subjective appetite and implicated hormones after a hypnosis-induced hallucinated meal: a randomized cross-over pilot trial.

The use of hypnosis can generate hallucinatory phenomena, which ranged from vivid/auditory imagery to fully developed "hallucinations" in selected people. The aim of this pilot trial was investigating the acute effects of a hypnosis-induced hallucinated breakfast (HB) compared to those of a real breakfast (RB) on subjective appetite and appetite-regulating hormones in highly hypnotizable individuals. Eight healthy post-menopausal women were recruited to consume two meals: the HB and the RB in a randomized crossover design. Participants underwent appetite sensations measurements (before meal and each 30-min until 270-min) and blood sample collection (at 0, 20, 60, 90, 180-min). A 3-day food-record was filled after each meal. The adjusted repeated measures ANCOVA did not show any meal×time interactions on subjective appetite postprandially. As expected, significantly higher glucose (p < 0.001), insulin (p < 0.001), and lower free fatty acid (p < 0.001) concentrations were found after the RB, but not following HB. Furthermore, RB significantly increased postprandial levels of glucagon-like-peptide-1 and peptide-YY at 20, 60, 90 and 180-min, whereas acylated-ghrelin and leptin levels did not differ. Postprandial neuropeptide-Y and orexin-A values significantly increased at different time-points after RB, but not following HB, while α-melanocyte-stimulating hormone levels enhanced after HB only. Energy intakes were significantly lower after HB on the test-day only (HB = 1146.6 ± 343.8 vs RB = 1634.7 ± 274.2kcal/d; p = 0.003). Appetite sensation might be modulated by fully developed meal "hallucination" induced by hypnosis, likely affecting brain-peptides implicated in the appetite regulation. However, further studies are needed to verify these results obtained in a highly selected group of individuals. NCT03934580.

Styles of Experiencing Hypnosis: A Replication and Extension Study

ABSTRACT Beyond hypnotizability, there may be different styles of experiencing hypnosis relevant to both basic research and clinical practice. Previous research has demonstrated the presence of inward attentive and dissociative subtypes among more highly hypnotizable individuals during a group protocol. With a sample of undergraduate students, we successfully replicated the presence of these 2 subtypes among those who were relatively more hypnotizable. Inward attentive and dissociative subtypes did not differ in their overall experience of the depth of the relationship with the hypnotist, though the dissociative subjects reported elevated everyday dissociative experiences. We then explored features of each subtype, noting possible altered memory experience in the dissociative style and reduced experience of rationality in both the inward attentive and dissociative styles. We discuss the scientific and clinical implications of this line of research.

The rubber hand illusion in hypnosis provides new insights into the sense of body ownership

Body ownership can be experimentally investigated with the rubber hand illusion (RHI), in which watching a rubber hand stroked synchronously with one’s own hidden hand induces a feeling of ownership over the rubber hand. The aim of this study was to investigate response to the RHI in high (N = 21) and low (N = 19) hypnotizable individuals in normal waking state and in hypnosis. Response to the RHI was measured via a question on the illusory feeling of ownership and with proprioceptive drift. The Highs expressed an overall feeling of more ownership over the rubber hand in both the normal waking state and hypnosis, although both groups gave higher ownership scores after synchronous than after asynchronous stroking and the difference between conditions was similar across groups. Conversely, the proprioceptive drift appeared to be differentially modulated by hypnosis and hypnotic suggestibility: it was increased in the Highs and decreased in the Lows after hypnosis induction. These findings hint at an interplay between hypnotic suggestibility and hypnosis in modulating response to the RHI. The selective breakdown of proprioceptive drift among the Lows suggests resistance to recalibrate one’s own limb in hypnosis.

High Motor Cortex Excitability in Highly Hypnotizable Individuals: A Favourable Factor for Neuroplasticity?

Hypnotizability is a psychophysiological trait associated with morphofunctional brain peculiarities and with several cognitive, sensorimotor and cardiovascular correlates. Behavioral and EEG studies indicate stronger functional equivalence (FE) between motor imagery and action in the individuals with high hypnotizability scores (Highs). We hypothesized that stronger FE leading to greater proneness to ideomotor behavior could be due to greater cortical excitability of the motor cortex. The aim of the study was to evaluate the motor cortical excitability through measurements of the muscle potentials (MEPs) evoked in the left abductor pollicis brevis by transcranial magnetic stimulation (TMS) of the right motor cortex in 10 Highs, 10 medium (Mediums) and 10 low hypnotizable individuals (Lows) classified according to the Stanford Hypnotic Susceptibility Scale, form A (SHSS). They were studied in basal conditions (B) and during motor imagery (MI). Results showed significant, negative correlations (i) between hypnotizability and MEPs Resting Motor Threshold (RMT) in basal conditions, and (ii) between hypnotizability and both MEPs RMT and suprathreshold (I1mv) stimulation intensities during MI. ANOVA revealed significantly lower stimulation intensities in Highs than in Lows, with Mediums exhibiting intermediate values. Thus, the Highs’ greater cortical excitability could sustain their greater FE and proneness to ideomotor behavior. In cognitive neuroscience these findings are relevant to the physiological interpretation of the response to sensorimotor suggestions by participants in the ordinary state of consciousness. In the clinical field they can predict the efficacy of mental training based on motor imagery and, possibly, the degree of imagery-induced cortical plasticity.

HYPNOTIZABILITY-RELATED FAAH C385A POLYMORPHISM: POSSIBLE ENDOCANNABINOID CONTRIBUTION TO SUGGESTION-INDUCED ANALGESIA

ABSTRACT Fatty acid amide hydrolase (FAAH) degrades the endogenous endocannabinoid (eCB) anandamide and might be involved in the response to suggestions of analgesia in subjects with high hypnotizability scores (highs). Since the A allele of the FAAH C385A polymorphism (rs324420) is associated with lower FAAH activity, it was studied in 21 highs, 66 low hypnotizable individuals (lows), and 172 individuals not selected for hypnotizability (controls) representing the general population. No significant difference was observed among groups, but the A allele frequency showed a significant trend to increase from lows to controls and from controls to highs. Since eCB small differences can be amplified by eCB interactions with other neurotransmitters, a contribution of the FAAH polymorphism to the highs’ analgesia should not be excluded.

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.

Hypnotic and non-hypnotic suggestion to ignore pre-cues decreases space-valence congruency effects in highly hypnotizable individuals.

Previous studies have shown that the speed of identifying emotional words is affected by pre-cues of up or down arrows, called the space-valence congruency effect (Zhang, Hu, Zhang, & Wang, 2015). In the present study, we investigate whether this effect is influenced by hypnotic or non-hypnotic suggestions to ignore pre-cues in highly hypnotizable individuals (HHIs). In all conditions, target words (including positive words, negative words and neutral words) primed by up or down arrows were presented to pre-screened HHIs. They were asked to identify whether the target words had emotional valence. Behavioral results showed that the space-valence congruency effect was absent in the hypnotic and non-hypnotic suggestion groups, but present in the non-suggestion control group. Consistently, the amplitudes of P2 components elicited by negative words were significantly larger when primed by down than by up arrows in the non-suggestion control group, and this P2 effect was absent in the hypnotic and non-hypnotic suggestion groups. Moreover, the amplitudes of the late positive components (LPC) showed no significant arrow-priming difference for positive targets in the hypnotic-suggestion and control groups. However, in the non-hypnotic suggestion group, the amplitudes of LPC were significantly larger when primed by down than up arrows for positive targets. Our results showed that suggestions, even without a hypnotic induction, can de-automatize embodied emotional recognition processes and modulate early attentional processing.

Reconsidering the autohypnotic model of the dissociative disorders

ABSTRACTThe dissociative disorders field and the hypnosis field currently reject the autohypnotic model of the dissociative disorders, largely because many correlational studies have shown hypnotizability and dissociation to be minimally related (r = .12). Curiously, it is also widely accepted that dissociative patients are highly hypnotizable. If dissociative patients are highly hypnotizable because only highly hypnotizable individuals can develop a dissociative disorder – as the author proposes – then the methodology of correlational studies of hypnotizability and dissociation in random clinical and community samples would necessarily be constitutively unable to detect, and statistically unable to reflect, that fact. That is, the autohypnotic, dissociative distancing of that small subset of highly hypnotizable individuals who repeatedly encountered intolerable circumstances is statistically lost among the data of (1) the highly hypnotizable subjects who do not dissociate and (2) subjects (of all levels of hypnotizability) who manifest other kinds of dissociation. The author proposes that, when highly hypnotizable individuals repeatedly engage in autohypnotic distancing from intolerable circumstances, they develop an overlearned, highly-motivated, automatized pattern of dissociative self-protection (i.e., a dissociative disorder). The author urges that theorists of hypnosis and the dissociative disorders explicitly include in their theories (a) the trait of high hypnotizability, (b) the phenomena of autohypnosis, and (c) the manifestations of systematized, autohypnotic pathology. Said differently, the author is suggesting that autohypnosis and autohypnotic pathology are unacknowledged nodes in the nomothetic networks of both hypnosis and dissociation.

Hypnotizability influences the cortical representation of visually and kinaesthetically imagined head position

The study investigates the cortical representation of the visual and kinesthetic image of a rotated position of the head in highly (highs) and low hypnotizable individuals (lows) of both gender. Participants were invited to imagine maintaining their head rotated toward one side by seeing their chin aligned with their right shoulder (V, visual imagery), and in a different condition, by feeling tension in their neck muscles (K, kinaesthetic imagery). Vividness of imagery and cognitive effort were reported after each task. Alpha and beta band absolute power was studied. Highs reported higher vividness than lows only for the kinaesthetic modality of imagery. The cortical desyncronization observed during visual and kinaesthetic imagery were different in high females (HM), low females (LF), high males (HM) and low males (LM). In fact, only HF and LM exhibited significant power changes during the kinaesthetic task, whereas visual imagery was associated with cortical desynchronization in all subgroups except HM. The study supports earlier findings of an advantage of highs in kinesthetic imagery, shows an intriguing interaction of hypnotizability and gender, and indicates topographical difference in the four subgroups of participants suggesting differences in underlying generators.

Polymorphism of Opioid Receptors μ1 in Highly HypnotizableSubjects

The possible cooperation between hypnotizability-related and placebo mechanisms in pain modulation has not been consistently assessed. Here, we investigate possible genetic bases for such cooperation. The OPRM1 gene, which encodes the μ1 opioid receptor—the primary site of action for endogenous and exogenous opioids—is polymorphic in the general population for the missense mutation Asn40Asp (A118G, rs1799971). The minor allele 118G results in decreased levels of OPRM1 mRNA and protein. As a consequence, G carriers are less responsive to opioids. The aim of the study was to investigate whether hypnotizability is associated with the presence of the OPRM1 polymorphism. Forty-three high and 60 low hypnotizable individuals, as well as 162 controls, were genotyped for the A118G polymorphism of OPRM1. The frequency of the G allele was significantly higher in highs compared to both lows and controls. Findings suggest that an inefficient opioid system may be a distinctive characteristic of highs and that hypnotic assessment may predict lower responsiveness to opioids.

Some needed psychological clarifications on the experience(s) of shamanism.

The target article's use of core concepts is confused and excessively broad. Two main types of experiences have been described in relation to shamanism: magical flight and mediumship/possession. The first refers to visual and remembered experiences of events in other realms, the second to embodied experiences of ceding mental control and personality to a preternatural entity. These experiences grossly correspond to two main experience modalities exhibited by highly hypnotizable individuals in a secular setting.

Hypnotic susceptibility and affective states in bipolar I and II disorders

BackgroundHighly hypnotizable individuals have impaired executive function, elevated motor impulsivity and increased emotional sensitivity, which are sometimes found in bipolar disorder patients. It is then reasonable to assume that certain aspects of hypnotic susceptibility differ with the types of bipolar disorder.MethodsThe Stanford Hypnotic Susceptibility Scale: Form C (SHSS:C) test, the Mood Disorder Questionnaire (MDQ), the Hypomanic Checklist-32 (HCL-32) and the Plutchick-van Praag Depression Inventory (PVP) were applied to 62 patients with bipolar I disorder, 33 bipolar II disorder, and 120 healthy volunteers.ResultsThe passing rate of the SHSS:C ‘Moving hands apart’ item was higher in bipolar I patients than in controls, whereas for ‘Mosquito hallucination’ the rate was lower. Bipolar I and II patients scored significantly higher on MDQ, HCL-32 and PVP scales than controls. The passing rates of ‘Mosquito hallucination’ in controls, ‘Arm rigidity’ in bipolar I, and ‘Age regression’ in bipolar II predicted the respective MDQ scores.ConclusionIn contrast to cognitive suggestions, bipolar I patients followed motor suggestions more often under hypnosis. Furthermore, both bipolar disorder patients and healthy volunteers demonstrated associations between mania levels and certain hypnotic susceptibility features. Our study aids in better understanding the altered conscious states in bipolar disorders, and encourages the use of related psychotherapy for these patients.