Suggestibility, expectancy, trance state effects, and hypnotic depth: I. Implications for understanding hypnotism

Intimate relationships and hypnosis: insecure adult attachment affects emotions and absorption during hypnosis

Introduction

Hypnosis research indicates that subjects are not equally hypnotizable. Most studies on hypnotizability focused on the relationships with personality or cognitive variables. At the same time, only a few proposed the contribution of the attachment style, defined as the result of the childhood relationship with the caregivers and influencing the adult relations.

Methods

In the present investigation, two studies were carried out to test the possible association between adult attachment and hypnotic responsivity. The adult attachment was assessed using the Experiences in Close Relationships-Revised (ECR-R) questionnaire, while hypnosis was assessed through the Harvard Group Scale of Hypnotic Susceptibility (HGSHS:A; Study 1) and the Phenomenology of Consciousness Inventory: Hypnotic Assessment Procedure (PCI-HAP; Study 2) in order to adopt a behavioral and a phenomenological approach, respectively.

Results

Analyses showed that attachment factors (anxiety and avoidance) were not associated with the level of hypnotizability, whereas it was associated with variations of consciousness during hypnosis, mainly internal dialogue, absorption and negative emotions. Overall, the insecure attachment styles yielded increased mind wandering and restlessness during hypnosis when compared to the secure style. The reason probably lies in the feeling of anxiety or danger of insecurely attached individuals when involved in intimate or confidential relationships.

Conclusion

These findings clarify a still poorly investigated aspect concerning the influence of attachment style on hypnotic experience and further highlight the need to consider inter-individual differences and the phenomenological perspective when assessing hypnosis and hypnotizability.

Hypnosis measured with monitors of anesthetic depth - EEG changes during the test for Harvard Group Scale of Hypnotic Susceptibility

Introduction

Hypnotic trance can be defined as a non-ordinary state of consciousness that is accompanied by a number of neurophysiological changes, including brain electrophysiology. In addition to subjective measures, corresponding objective parameters are needed in experimental and clinical hypnosis research but are complex, impractical, or unspecific. A similar challenge exists for the measurement and monitoring of drug-induced hypnosis, namely general anesthesia. The observation of changes in EEG induced by narcotics has led to the development of monitors for the depth of anesthesia based on EEG parameters. We investigated whether two such monitors react to the induction and maintenance of hypnosis during a highly standardized procedure.

Methods

A total of 56 volunteers were monitored for the bispectral index (BIS) and cerebral state index (CSI) (range 0-100, >95 considered "awake") during the Harvard Group Scale of Hypnotic Susceptibility test. For this test, trance is induced by a taped text and followed by 12 tasks performed under hypnosis. In contrast to random forms of hypnosis, this represents a standardized, worldwide-established condition. According to the resulting score, participants were classified into suggestibility groups in order to evaluate whether the electrophysiological measurements of BIS and CIS indices differ between high and low suggestible persons. Furthermore, participants were asked to rate their hypnotic depth (HD, 1-10) at every task of the test.

Results

Scores dropped significantly from a mean of 97.7 to 86.4 for BIS and from 94.6 to 77.7 for CSI with the induction of hypnosis to stay throughout hypnosis at levels of approximately 88.6 or 82.9, respectively. Results did not differ between high- and low-suggestible participants. The means of the subjective score of hypnotic depth and of the electrophysiological measurements showed a similar course. However, no correlation was found between BIS or CSI values and scores of hypnotic depths.

Conclusion

Monitors for depth of anesthesia respond to changes in consciousness, including trance states of hypnosis. However, specificity is unclear. Practically, in hypnosis research with the exclusion of drug effects or sleep, these monitors might be helpful to test and compare the efficacy of induction texts and to detect disturbances of trance state.

Real-time assessment of hypnotic depth, using an EEG-based brain-computer interface: a preliminary study

OBJECTIVE

Hypnosis can be an effective treatment for many conditions, and there have been attempts to develop instrumental approaches to continuously monitor hypnotic state level ("depth"). However, there is no method that addresses the individual variability of electrophysiological hypnotic correlates. We explore the possibility of using an EEG-based passive brain-computer interface (pBCI) for real-time, individualised estimation of the hypnosis deepening process.

RESULTS

The wakefulness and deep hypnosis intervals were manually defined and labelled in 27 electroencephalographic (EEG) recordings obtained from eight outpatients after hypnosis sessions. Spectral analysis showed that EEG correlates of deep hypnosis were relatively stable in each patient throughout the treatment but varied between patients. Data from each first session was used to train classification models to continuously assess deep hypnosis probability in subsequent sessions. Models trained using four frequency bands (1.5-45, 1.5-8, 1.5-14, and 4-15 Hz) showed accuracy mostly exceeding 85% in a 10-fold cross-validation. Real-time classification accuracy was also acceptable, so at least one of the four bands yielded results exceeding 74% in any session. The best results averaged across all sessions were obtained using 1.5-14 and 4-15 Hz, with an accuracy of 82%. The revealed issues are also discussed.

Transcranial electrical stimulation of the prefrontal cortex to boost the hypnosis experience: who benefits most?

Many attempts have been made to enhance hypnotizability. The most recent studies adopted the non-invasive brain stimulation to deactivate the dorsolateral prefrontal cortex (DLPFC) during hypnosis, indicating this as a promising approach. However, it is still no clear whether individual factors can predict the effects of stimulation on hypnotizability. In the present study we adopted the phenomenological consciousness inventory (PCI) to retrospectively assess the mental processes during hypnosis and to predict hypnotizability, here defined as "hypnoidal state." The aim was to investigate the possible role of the hypnotic susceptibility on the efficacy of a validated approach of hypnosis enhancement through cathodal transcranial electrical stimulation (tDCS) of the left DLPFC. Results indicated that the lower hypnoidal state at baseline predicted the greater enhancement after the active tDCS. These findings suggest the subjects with lower hypnotic responsiveness as the best candidates for the tDCS interventions of hypnosis enhancement, at least for the montage targeting the left DLPFC. Neurocognitive underpinnings and clinical implications of the results are discussed.

Is Hypnotic Induction Necessary to Experience Hypnosis and Responsible for Changes in Brain Activity?

The relevance of formal hypnotic induction to the experience of trance and its neural correlates is not clear, in that hypnotizability, beliefs and expectation of hypnosis may play a major role. The aim of the study was assessing the EEG brain activity of participants with high (highs) or low hypnotizability scores (lows), aware of their hypnotizability level and informed that the session will include simple relaxation, formal hypnotic induction and neutral hypnosis. A total of 16 highs and 15 lows (according to the Stanford Hypnotic Susceptibility Scale, form A) were enrolled. Their EEGs were recorded during consecutive conditions of open/closed-eyes relaxation, hypnotic induction, neutral hypnosis and post hypnosis not interrupted by interviews. The studied variables were theta, alpha and gamma power spectral density (PSD), and the Determinism (DET) and Entropy (ENT) of the EEG signal Multidimensional Recurrence Plot (mRP). Highs reported significantly greater changes in their state of consciousness than lows across the session. The theta, alpha and gamma PSD did not exhibit condition-related changes in both groups. The Alpha PSD was larger in highs than in lows on midline sites, and the different sides/regions' theta and gamma PSD were observed in the two groups independently from conditions. ENT showed no correlation with hypnotizability, while DET positively correlated with hypnotizability during hypnosis. In conclusion, the relevance of formal hypnotic induction to the experience of trance may be scarce in highs, as they are aware of their hypnotizability scores and expecting hypnosis. Cognitive processing varies throughout the session depending on the hypnotizability level.

Evaluating brain spectral and connectivity differences between silent mind-wandering and trance states

Trance is an altered state of consciousness characterized by alterations in cognition. In general, trance states induce mental silence (i.e., cognitive thought reduction), and mental silence can induce trance states. Conversely, mind-wandering is the mind's propensity to stray its attention away from the task at hand and toward content irrelevant to the current moment, and its main component is inner speech. Building on the previous literature on mental silence and trance states and incorporating inverse source reconstruction advances, the study's objectives were to evaluate differences between trance and mind-wandering states using: (1) electroencephalography (EEG) power spectra at the electrode level, (2) power spectra at the area level (source reconstructed signal), and (3) EEG functional connectivity between these areas (i.e., how they interact). The relationship between subjective trance depths ratings and whole-brain connectivity during trance was also evaluated. Spectral analyses revealed increased delta and theta power in the frontal region and increased gamma in the centro-parietal region during mind-wandering, whereas trance showed increased beta and gamma power in the frontal region. Power spectra at the area level and pairwise comparisons of the connectivity between these areas demonstrated no significant difference between the two states. However, subjective trance depth ratings were inversely correlated with whole-brain connectivity in all frequency bands (i.e., deeper trance is associated with less large-scale connectivity). Trance allows one to enter mentally silent states and explore their neurophenomenological processes. Limitations and future directions are discussed.

In medio stat virtus: The importance of studying mediums in hypnosis research

Most of the experimental investigations on hypnosis used to compare small samples of individuals with low or high responsiveness to hypnosis by systematically excluding medium responders. The present article underlines the limitations of this methodological approach that may have partially weakened the scientific impact of hypnosis research. In fact, the mediums-neglecting bias might be one of the reasons why some investigations suffer from low replicability and generalizability. Themes such as hypnotizability scales, suggestibility, statistical power, and research design are critically reviewed with the aim of proposing a more rigorous approach that boost up impact and reliability of hypnosis research. In particular, the recruitment of medium hypnotizables and the adoption of a within-instead of a between-subjects design currently seem to be some of the best recommendations for strengthening hypnosis research, as well as to renew the dialogue between clinical and experimental hypnosis.

Boosting the hypnotic experience. Inhibition of the dorsolateral prefrontal cortex alters hypnotizability and sense of agency. A randomized, double-blind and sham-controlled tDCS study

Hypnotizability refers to the individual responsiveness to hypnosis, and literature shows that the greater the hypnotizability, the more effective the hypnotic suggestions. So far, few studies attempted to enhance hypnotizability, and only two adopted brain stimulation with magnetic pulses. In the present study, we aimed to boost hypnotizability through transcranial direct current stimulation (tDCS). To this aim, bilateral tDCS was applied over the dorsolateral prefrontal cortex (DLPFC) with the target electrode providing negative current (cathodal stimulation) over the left hemisphere. Twenty-nine subjects participated in the study and they were randomly assigned to the sham or the active group in a double-blind design. The hypnotic experience was assessed before and after the stimulation through a phenomenological measure of consciousness (the PCI-HAP). The main findings revealed that a single tDCS session enhanced the hypnotic depth by 11% and reduced the volitional control by 30%, while no differences emerged in the sham group. This is the first study adopting the electrical neurostimulation to produce an alteration of hypnotizability and sense of agency, and confirmed the key-role of the DLPFC and executive control in the hypnotic phenomena. If confirmed, these findings could have relevant implications as enhanced hypnotizability could be translated into better outcomes for many hypnotic interventions.

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.

FUNCTIONAL CHANGES IN BRAIN ACTIVITY AFTER HYPNOSIS: Neurobiological Mechanisms and Application to Patients with a Specific Phobia-Limitations and Future Directions

Studies of brain-plasticity changes in hypnosis using functional magnetic resonance imaging (fMRI), positron-emission-tomography (PET) and electroencephalography (EEG) were reviewed. The authors found evidence in those studies that hypnosis is a powerful and successful method for inhibiting the reaction of the fear circuitry structures. Limitations of the studies were critically discussed, and implications for future research were made. The authors are currently using a portable fNIRS apparatus to integrate the scanning device into real life situations in medical practice. Their aim is to disentangle the neuronal mechanisms and physiological correlates in patients with severe fear of medical treatments when directly confronted with anxiety-provoking stimuli and to assess the effects of a brief hypnosis. Drawing on evidence from several technological modalities, neuroimaging and physiological studies pave the road to a better scientific understanding of neural mechanisms of hypnosis.

A Pragmatic Guide to the Setting up of Integrated Hypnotherapy Services in Primary Care and Clinical Settings

Despite the continued debate and lack of a clear consensus about the true nature of the hypnotic phenomenon, hypnosis is increasingly being utilized successfully in many medical, health, and psychological spheres as a research method, motivational tool, and therapeutic modality. Significantly, however, although hypnotherapy is widely advertised, advocated, and employed in the private medical arena for the management and treatment of many physical and emotional disorders, too little appears to be being done to integrate hypnosis into primary care and national health medical services. This article discusses some of the reasons for the apparent reluctance of medical and scientific health professionals to consider incorporating hypnosis into their medical practice, including the practical problems inherent in using hypnosis in a medical context and some possible solutions.

Changes in the sense of agency during hypnosis: The Hungarian version of the Sense of Agency Rating Scale (SOARS-HU) and its relationship with phenomenological aspects of consciousness

Changes in the sense of agency are defining feature of hypnosis. The Sense of Agency Rating Scale (SOARS) is a 10-item questionnaire, administered after a hypnosis session to assess alteration in the sense of agency. In the present study, a Hungarian version of the measure (SOARS-HU) is presented. The SOARS-HU and the Phenomenology of Consciousness Inventory (PCI) were administered to 197 subjects following hypnotizability screening with the Harvard Group Scale of Hypnotic Susceptibility Scale, Form A (HGSHS:A). Confirmatory factor analysis and correlations with hypnotizability demonstrate the reliability and validity of the SOARS-HU. Changes in the Involuntariness and Effortlessness subscales of the SOARS-HU were associated with alterations in subjective conscious experience, as measured by the PCI. These changes in subjective experience remained significant after controlling for HGSHS:A scores. These results indicate that changes in the sense of agency during hypnosis are associated with alterations of consciousness that are independent of hypnotizability.

Is high hypnotizability a necessary diathesis for pathological dissociation?

During the 19th century, high hypnotizability was considered to be a form of psychopathology that was inseparable from hysteria. Today, hypnotizability is considered to be a normal trait that has no meaningful relationship with psychopathology. Psychiatric patients generally manifest medium to low hypnotizability. Nevertheless, several psychiatric diagnoses are marked by an unexpectedly large proportion of patients with high hypnotizability. This is especially true of the diagnostic categories that were subsumed by the 19th-century concept of hysteria: dissociative identity disorder, somatization disorder, and complex conversion disorders. These hysteria-related modern diagnoses are also highly dissociative. A review and analysis of the literature regarding the relationship between hypnotizability and dissociation indicates that high hypnotizability is almost certainly a necessary diathesis for the development of a severe dissociative disorder. Such a diathesis has significant implications for (a) the psychiatric nosologies of the American Psychiatric Association and the World Health Organization, (b) the hypnosis field, and (c) the etiology and construct validity of dissociative identity disorder and other severe dissociative disorders. Specifically, the dissociative disorders (excepting depersonalization disorder, which is not classified as a dissociative disorder by the World Health Organization) are manifestations of hypnotic pathology.

Psychological Features of Hypnotizability: A First Step Towards Its Empirical Definition

This study examined the relationship between the Hypnotic Induction Profile (HIP) and several psychological tests: Tellegen Absorption Scale (TAS), Spontaneity Assessment Inventory-Revised (SAI-R), Dissociative Experiences Scale (DES), Short-Form Boundary Questionnaire (SFBQ), Mini Locus of Control (MLOC), Testoni Death Representation Scale (TDRS), and the Interpersonal Reactivity Index (IRI). Two hundred and forty volunteers were administered the above tests; 78 of them were also administered the HIP, and its scores were compared to those on the other tests. A significant correlation was found among the TAS, DES, SFBQ, and IRI. The HIP was significantly correlated to the DES (r = .19 p_1tail = .045), and the IRI-ec subscale (r = .19 p_1tail = .044); 14 test items from DES, IRI, TAS, SAIR, and SFBQ were also significantly related to the HIP. The findings suggest that hypnotizability may relate to stronger perception of the inner world, decreased aptitude for managing memory processing, and increased sensitivity and empathy.

Hypnotic approaches for chronic pain management: clinical implications of recent research findings

The empirical support for hypnosis for chronic pain management has flourished over the past two decades. Clinical trials show that hypnosis is effective for reducing chronic pain, although outcomes vary between individuals. The findings from these clinical trials also show that hypnotic treatments have a number of positive effects beyond pain control. Neurophysiological studies reveal that hypnotic analgesia has clear effects on brain and spinal-cord functioning that differ as a function of the specific hypnotic suggestions made, providing further evidence for the specific effects of hypnosis. The research results have important implications for how clinicians can help their clients experience maximum benefits from hypnosis and treatments that include hypnotic components.

Unconscious agendas in the etiology of refractory obesity and the role of hypnosis in their identification and resolution: a new paradigm for weight-management programs or a paradigm revisited?

Hypnosis has long been recognized as an effective tool for producing behavioral change in the eating disorders anorexia and bulimia. Despite many studies from the latter half of the last century suggesting that hypnosis might also be of value in managing obesity situations, the efficacy of hypnotherapy for weight reduction has received surprisingly little formal research attention since 2000. This review presents a brief history of early clinical studies using hypnosis for weight reduction and describes a hypnotherapeutic approach within which a combination of instructional/pedagogic and exploratory therapeutic sessions can work together synergistically to maximize the potential for sustained weight loss. Hypnotic modulation of appetite- and satiation-associated peptides and hormone levels may yield additional physiological benefits in Type 1 and Type 2 diabetes.

Trance state effects and imagery vividness before and during a hypnotic assessment: a preliminary study

This preliminary study explored the relationship between imagery vividness before and during a hypnotic phenomenological assessment procedure, the Phenomenology of Consciousness Inventory-Hypnotic Assessment Procedure (PCI-HAP), while also assessing trance (hypnoidal) state effects and several other variables. The PCI-HAP allows the assessment of trance state effects associated with hypnotism to be quantified and statistically assessed. The 102 subjects completed the PCI-HAP along with several other questionnaire items. Correlational and regression analyses suggested that imagery vividness during hypnotism (hypnotic imagoic suggestibility) was predicted by combined imagery vividness before hypnotism and trance (altered) state effects during hypnotism. When measuring several additional variables, imagery vividness during hypnotism was found to be a function of self-reported hypnotic depth and additional other variables. The usefulness of these results for better understanding imagery vividness before and during hypnotism is discussed.