Hypnotic Responsiveness Research Articles

Does counterpain imagery mediate hypnotic analgesia?

Sixty-six high hypnotizable individuals received a baseline exposure to pain and 2 counterbalanced hypnotic analgesia conditions. Standard analgesia invoked counterpain imagery, whereas imageless analgesia proscribed imagery. The mean level of pain reduction in these 2 conditions was virtually identical and significantly less than the pain rated in the baseline condition. Furthermore, cognitions experienced as active efforts to cope with the pain occurred far less often and were associated with less pain reduction than cognitions experienced as passive concomitants of pain reduction. The results cast considerable doubt on the widespread assumption that imaginative involvement mediates hypnotic responding.

A spectral analysis of cognitive and personality variables in hypnosis: Empirical disconfirmation of the two-factor model of hypnotic responding.

A spectral analysis of cognitive and personality variables in hypnosis: Empirical disconfirmation of the two-factor model of hypnotic responding.

The Computer-Assisted Hypnosis Scale: Standardization and norming of a computer-administered measure of hypnotic ability.

In a counterbalanced, within-subjects, repeated measures design, 130 participants were administered both the Computer-Assisted Hypnosis Scale (CAHS; C. D. Grant, 1993) and the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C; A. M. Weitzenhoffer & E. R. Hilgard, 1962). For each hypnotic procedure, responsiveness was assessed along three dimensions: behavioral (CAHS, SHSS: C), subjective depth (Field Depth Inventory; P. B. Field, 1965), and relational involvement (Archaic Involvement Measure; M. R. Nash & D. Spinler, 1989). The CAHS was shown to be a psychometrically sound instrument for measuring hypnotic ability. The various dimensions of CAHS hypnotic responsiveness were highly positively related, and the CAHS compared favorably with the SHSS: C across the three dimensions assessed. Results are discussed in terms of the theory and practice of clinical assessment, noting directions for future research

Perturbation of Ion Channel Conductance Alters the Hypnotic Response to the α2-Adrenergic Agonist Dexmedetomidine in the Locus Coeruleus of the Rat

The alpha 2-adrenergic agonists are members of a novel class of hypnotic-anesthetic agents that selectively bind to alpha 2 adrenoceptors in the locus coeruleus (LC) to initiate their pharmacologic action. The postreceptor molecular mechanism of the hypnotic action of alpha 2-adrenergic agonists remains unknown. In this study we addressed the role of conductance through a variety of calcium and potassium ion channels in the hypnotic action of dexmedetomidine in the LC of the rat. Cannulas were inserted stereotactically into the LC of halothane-anesthetized rats (n = 318). After at least 48 h, rats were tested for loss of righting reflex in response to administration of the alpha 2-adrenergic agonist dexmedetomidine at a hypnotic (7.0 micrograms LC) or subhypnotic (3.5 micrograms LC) dose. To establish the mediating role of various species of calcium and potassium ion channels in the hypnotic response, rats were pretreated with the following drugs before the administration of dexmedetomidine LC:S(+)202791 (L-type calcium-channel activator), nifedipine and R(-)202791 (L-type calcium-channel blocker), SNX 111 (N-type calcium-channel blocker), SNX 230 (P-type calcium-channel blocker), quinine (calcium-activated and voltage-gated potassium-channel blocker), charybdotoxin (calcium-activated potassium-channel blocker), dendrotoxin (voltage-gated potassium-channel blocker), or glybenclamide (adenosine triphosphate-sensitive potassium-channel blocker). The drugs were used in doses not causing behavioral effects that could have confounded the interpretation of loss of righting reflex. SNX 230 and the dihydropyridines nifedipine and R(-)202791 produced loss of righting reflex in the presence of a subhypnotic dose of dexmedetomidine. The hypnotic-enhancing effects of the dihydropyridines could be blocked with S(+)202791, which also diminished loss of righting reflex in response to dexmedetomidine 7.0 micrograms LC. Quinine, dendrotoxin, and charybdotoxin each attenuated the hypnotic response to dexmedetomidine 7.0 micrograms LC. The hypnotic response to dexmedetomidine was not significantly altered by SNX 111 or glybenclamide. Inhibition of ion conductance through L- or P-type calcium channels and facilitation of conductance through voltage-gated or calcium-activated potassium channels may be involved in the mechanism of hypnotic action of alpha 2-adrenergic agonists. These changes in ion conductance were capable of producing membrane hyperpolarization and decreasing neuronal excitability. There was no evidence for the involvement of adenosine triphosphate-sensitive potassium channels or N-type calcium channels in the hypnotic response to dexmedetomidine.

Heart rate and heart-rate variability during hypnotic responding

Humans have limited capacity of processing just up to 4 integrated items of information in the working memory. Thus, it is inevitable to commit more errors when challenged with high memory loads. However, the neural mechanisms that determine the accuracy of response at high memory loads still remain unclear. High temporal resolution of Electroencephalography (EEG) technique makes it the best tool to resolve the temporal dynamics of brain networks. EEG-defined microstate is the quasi-stable scalp electrical potential topography that represents the momentary functional state of brain. Thus, it has been possible to assess the information processing currently performed by the brain using EEG microstate analysis. We hypothesize that the EEG microstate preceding the trial could determine its outcome in a visuospatial working memory (VSWM) task. Twenty-four healthy participants performed a high memory load VSWM task, while their brain activity was recorded using EEG. Four microstate maps were found to represent the functional brain state prior to the trials in the VSWM task. One pre-trial microstate map was found to determine the accuracy of subsequent behavioural response. The intracranial generators of the pre-trial microstate map that determined the response accuracy were localized to the visuospatial processing areas at bilateral occipital, right temporal and limbic cortices. Our results imply that the behavioural outcome in a VSWM task could be determined by the intensity of activation of memory representations in the visuospatial processing brain regions prior to the trial.

Hypnotizability Enhancement: Clinical Implications of Empirical Findings

While some conceptualize hypnotizability as a stable attribute of the individual, there is a growing body of literature that indicates hypnotizability may be characterized as a constellation of potentially modifiable attitudes and skills that are strongly influenced by contextual factors. In this article I briefly review representative studies from the hypnotizability-enhancement literature and highlight several controversial issues that have emerged. Although the empirical debate regarding hypnotizability and its enhancement will continue, this literature review has produced findings that are of value to hypnotherapists who wish to facilitate optimal hypnotic responding and positive outcomes with their patients. Several of these findings and their implications for the clinical application of hypnosis are discussed.

Effect of pentobarbital and gaseous anesthetics on rats selectively bred for ethanol sensitivity

Rats have been genetically selected to have a differential hypnotic response to an acute injection of ethanol. These high alcohol sensitive (HAS) and low alcohol sensitive (LAS) rats were used to investigate commonalities of the mechanism of action of several gaseous anesthetics, pentobarbital and ethanol. Similar studies have been carried out extensively with mouse lines also differentially sensitive to ethanol (short- and long-sleep mice). Like the mice, the rats are also differentially sensitive to the two gaseous anesthetics, enflurane and isoflurane. However, in contrast to results with these mice, we find that the HAS and LAS rats are differentially sensitive to halothane and pentobarbital in the same direction as their sensitivity to ethanol. In other studies, the rats also have been found to be differentially sensitive to phenobarbital as are SS and LS mice. These results show that, by the use of these anesthetics in combination with selectively bred rodent lines, many new opportunities for dissecting the molecular mechanisms of anesthetic agents present themselves.

Chronic administration of an α2 adrenergic agonist desensitizes rats to the anesthetic effects of dexmedetomidine

α 2 adrenergic agonists are being administered perioperatively to facilitate the anesthetic management of the surgical patient. In some clinical settings, use of α 2 adrenergic agonists has been extended into the postoperative period to prolong the patients' sedative and stress-free state. We studied whether the administration of α 2 adrenergic agonists over an extended period of time would result in “desensitization” to the central actions of α 2 adrenergic agonists. Male Sprague-Dawley rats were administered dexmedetomidine, a highly selective α 2 adrenergic agonist, at rates varying between 1 and 10 μg·kg −1·h −1via a chronically implanted SC osmotic pump. Spontaneous locomotor activity, tested in an open-field box, was significantly lower in both 3- and 10-μg·kg −1·h −1 treatment groups but returned to normal by the second or sixth day, respectively. The hypnotic response to dexmedetomidine IP was decreasedin the 10-μg·kg −1·h −1 dose group from the second day, and by the fourth day in the 3-μg·kg −1·h −1 group. Recovery from the desensitized state was rapid and occurred on the third day after pump removal in the 3-μg·kg −1·h(su−1) group and by the fifth day after pump removal in the 10-μg·kg −1·h −1 dose group. By using a higher dose of dexmedetomidine IP (250 μg·kg in lieu of 100 μg/kg) at day 7 in “tolerant” rats, the hypnotic response could partially be “restored” towards normal. An attenuated hypnotic response could still be demonstrated even when dexmedetomidine was administered directly into the locus coeruleus (LC) in rats pretreated chronically with dexmedetomidine. In no case could hypnotic responsiveness be restored to normal by pretreating with the α 1 adrenergic antagonist prazosin. The minimum anesthetic concentration (MAC) for halothane was not altered in the “tolerant” rats. These data indicate that hyporesponsiveness develops to the central depressant effects of an α 2 adrenergic receptor agonist, through a pharmacodynamic mechanism.

Reporting Bias and Response to Difficult Suggestions in Highly Hypnotizable Hypnotic Subjects

The tendency of highly hypnotizable hypnotic subjects to bias their perceptual reports in terms of instructional demands but independently of any perceptual change was assessed. Subjects who biased their reports (i.e., biasers) were significantly more likely than nonbiasers to report intense subjective responses, exhibit high levels of amnesia, and report their responses as occurring involuntarily during preliminary hypnotizability testing. In addition, biasers attained higher scores than nonbiasers on Form II of the Stanford Profile Scale of Hypnotic Susceptibility (SPS: II; Weitzenhoffer & Hilgard, 1963), and all of those who scored in the "virtuoso" range of the SPS: II were classified as biasers. Findings support the hypothesis that subjects′ willingness to bias responses in terms of situational demands is a central component of hypnotic responding.

Surreptitiously observed hypnotic responding in simulators and in skill-trained and untrained high hypnotizables.

Low-hypnotizable Ss (LHs) administered cognitive skill training exhibited substantially higher posttest hypnotizability than LHs administered no treatment. Next, the Ss in these 2 conditions as well as Ss who attained high hypnotizability without training and LHs instructed to fake hypnosis (i.e., simulators) were individually tested for hypnotizability twice while their responses were recorded by a hidden camera. In the individual session, Ss were first tested for hypnotizability while alone and then tested again in the presence of an experimenter. The skill-trained Ss and high-hypo notizable controls attained equivalent (high) hypnotizability scores with the experimenter both absent and present

The clinical role of responsivity tests: a master class commentary.

Abstract What is the proper role of hypnotic responsivity tests in the clinical context? If a patient demonstrates a low score, should the clinician proceed to use hypnosis? To what extent should the patient's level of hypnotic responsivity guide the clinical use of hypnosis? If the initial hypnotic response is minimal, should the clinician proceed with the use of hypnosis?

Assessment of Hypnotic Processes and Responsiveness in a Clinical Context

The present study was designed to investigate in a clinical situation whether differences in measured hypnotizability validly reflect differences in hypnotic processes and to what extent factors deemed extraneous to hypnosis--such as resistance--influence hypnotic responding. To answer this question, Dutch versions of relevant scales had to first be developed. The factorial validity and reliability of a Dutch translation of the Resistance Toward Hypnosis Scale (DRHS) and a shortened Dutch version of the Phenomenology of Consciousness Inventory (DPCI) were investigated in a sample of 205 psychiatric patients. The DRHS proved to be factorially valid and reliable, and two subscales, Trance and Reality Orientation, derived empirically from the DPCI showed good to satisfactory reliability. In a second study with a subsample of 99 psychiatric patients, hypnotizability as measured by the Stanford Hypnotic Clinical Scale for Adults was strongly and positively related to DPCI Trance scores and moderately and negatively related to DPCI Reality Orientation and DRHS Resistance scores. It is concluded that hypnotizability as measured in a clinical context under standard conditions is strongly related to hypnotic experiences over and above the moderate effects of resistance toward hypnosis and hypnotic suggestions. Standard hypnotizability assessments appear to be similar in their meaning in an experimental and clinical context.

Response Expectancy as a Mediator of Hypnotizability Modification: A Brief Communication

The role of response expectancy in bringing about increases in hypnotic susceptibility by use of the Carleton Skill Training Program (CSTP) was assessed with 27 subjects selected for their low hypnotizability scores. Subjects were randomly assigned to one of two conditions: 13 received the CSTP to increase their hypnotic susceptibility, and 14 received no training. In addition to assessing hypnotizability, hypnotic response expectancies were assessed before and after training. With pretreatment hypnotizability controlled, subjects in the training group scored significantly higher than control subjects on all self-report measures of hypnotizability but not on a measure of observed behavioral response. Changes in response expectancy were found to be highly correlated with changes in hypnotizability. With changes in expectancy controlled, no significant differences between the trained and control groups were found.

Contemporary hypnosis research

Part I: Theoretical and Historical Perspectives. Woody, Bowers, Oakman, A Conceptual Analysis of Hypnotic Responsiveness: Experience, Individual Differences, and Context. Dixon, Laurence, Two Hundred Years of Hypnosis Research: Questions Resolved? Questions Unanswered! Part II: Current Empirically Based Theories. Hilgard, Dissociation and Theories of Hypnosis. Spanos, Coe, A Social-Psychological Approach to Hypnosis. Fromm, An Ego-Psychological Theory of Hypnosis. Nash, Hypnosis, Psychopathology, and Psychological Regression. Part III: Surveys of Broad Areas. Barabasz, Barabasz, Research Designs and Considerations. Holroyd, Hypnosis as a Methodology in Psychological Research. Crawford, Gruzelier, A Midstream View of the Neuropsychophysiology of Hypnosis. Kirsch, Council, Situational and Personality Correlates of Hypnotic Responsiveness. Lynn, Sivec, The Hypnotizable Subject as Creative Problem-Solving Agent. Shames, Bowers, Hypnosis and Creativity. Sheehan, The Phenomenology of Hypnosis and the Experiential Analysis Technique. Kahn, Fromm, Self-Hypnosis, Personality, and the Experiential Method. McConkey, The Effects of Hypnotic Procedures on Remembering: The Experimental Findings and Their Implication for Forensic Hypnosis. Brown, Clinical Hypnosis Research since 1986. Perry, Nadon, Button, The Measurement of Hypnotic Ability.

Alpha 2-agonists in anesthesia and intensive medicine

The neurotransmitters adrenaline and noradrenaline are non-selective adrenergic agonists which interact with both subtypes of alpha- and beta-receptors. Clonidine, an alpha 2-adrenergic drug with a selectivity ratio of 200/1 for alpha 2/alpha 1 has been used in clinical practice for more than 20 years. Although alpha 2-agonists have vasoconstrictor properties, sympatholytic effects on the central nervous system predominate. As a result, the sympathetic outflow from the medullary pressor centres is decreased mediating the hypotensive effects of the alpha 2-agonists. These compounds also exhibit sedative, anxiolytic, analgesic, and haemodynamic stabilising properties. The identification of alpha 2-adrenoceptors has yielded information on their biochemical properties, signal transduction, modulation of the sympathetic nervous system and neurotransmission. The classification of alpha 2-receptors based on anatomical locations and identified as presynaptic alpha 2-receptors and postsynaptic alpha 1-receptors proved to be untenable after postsynaptic and extrasynaptic alpha 2-receptor locations had been identified. At least 3 isoreceptors which are heterologously distributed in the brain have been identified. Guanine nucleotide proteins (G proteins) couple the receptor to an effector mechanism (i.e. intracellular messenger cascade, ion channel). More selective for the alpha 2-adrenoceptor than clonidine is dexmedetomidine (1600/1 of alpha 2/alpha 1), a very potent agonist at the alpha 2-adrenoceptor. Imidazole derivatives (like clonidine and dexmedetomidine) also bind to other nonadrenergic receptors ("imidazoline receptors") which may produce some effects (i.e. vagotonia) previously ascribed to alpha 2-adrenoceptors. alpha 2-receptors exist in brain tissue and several peripheral organs and tissues including the liver, eye, kidney, pancreas and platelets. Anaesthetic interest has focussed on reductions in anaesthetic requirements since experimental and clinical studies have shown that alpha 2-agonists expert powerful analgesic and anaesthetic effects. The hypnotic response is probably mediated by activation of alpha 2-adrenoceptors in the locus coeruleus. Analgesia is induced by modulation of the nociceptive pathway at the level of the dorsal root neuron and other sites not yet unambiguously characterised. Dexmedetomidine reduces the anaesthetic requirements for halothane by more than 90%. Cerebral blood flow and intraocular pressure are reduced by alpha 2-agonists. Epidural, intrathecal, intravenous and transdermal application of clonidine resulted in pain reduction, during and following surgery and in patients with neurogenic or otherwise intractable cancer pain. Administration of alpha 2-agonists induces only minor respiratory effects. Salivary flow is reduced by alpha 2-agonists and gastric and small-bowel motility is decreased.(ABSTRACT TRUNCATED AT 400 WORDS)

Response expectancies and interpretations as determinants of hypnotic responding.

Ss rated the extent to which they expected to respond to each of the suggestions on a hypnotizability scale both before and after the administration of the preliminary hypnotic induction procedure. After the induction, Ss also rated the extent to which they planned to respond actively and passively to each suggestion. Contrary to strong versions of response-expectancy theory, the extent to which Ss planned to adopt an active interpretation predicted behavioral and subjective indexes of hypnotizability even after controlling for the effects of postinduction expectations. In addition, an active interpretation significantly predicted response to suggestion for which Ss held weak and uncertain expectations. The relationship between expectation and hypnotizability was found to be fan-shaped rather than linear. Implications are discussed.

Response expectancies and interpretations as determinants of hypnotic responding.

Response expectancies and interpretations as determinants of hypnotic responding.

Surreptitiously observed hypnotic responding in simulators and in skill-trained and untrained high hypnotizables.

Surreptitiously observed hypnotic responding in simulators and in skill-trained and untrained high hypnotizables.

Day persons, night persons, and variability in hypnotic susceptibility.

Day persons (those most alert during daytime hours) and night persons participated in 2 experiments to examine within-subject variability of scores over time on the Harvard Group Scale of Hypnotic Susceptibility, Form A, and the Stanford Hypnotic Susceptibility Scale, Form C. Regardless of scale used, day persons exhibited peak susceptibility at 10 a.m. and 2 p.m.; for night persons, peak susceptibility was found at 1 p.m. and between 6 p.m. and 9 p.m. Furthermore, 2 peaks of temperature increase (1 p.m. and 6 p.m.) appeared to be associated with peaks in hypnotic susceptibility. However, such was shown to be associated with periods of food intake rather than with increases in hypnotic susceptibility. Results are examined with respect to methodological concerns and the potential existence of ultradian rhythms for hypnotic responsiveness.

Pertussis toxin-mediated ribosylation of G proteins blocks the hypnotic response to an α2-agonist in the locus coeruleus of the rat

Biologic responses mediated by adrenoceptors are transduced by a receptor-effector mechanism that involves a guanine nucleotide binding protein (G protein). Recently, we determined that the transduction mechanism for the hypnotic response to dexmedetomidine, a highly selective α 2-agonist, is located in the locus coeruleus (LC) of the rat. In this study, we examined the role of pertussis toxin-sensitive (PTX) G proteins in the LC for the hypnotic response to dexmedetomidine. The LC of rats were stereotactically cannulated and treated with PTX, 0.34 μg, or vehicle. Five days later, the hypnotic response to dexmedetomidine, 7 μg into the LC or 50 μg · kg −1 IP, was tested. On the following day, the LC was harvested and assayed to determine whether the G proteins had been ribosylated by pretreatment with PTX in vivo. Quantitative immunoblotting of G 0α, G iα1,2, and G iα3, the α-subunit of three PTX-sensitive proteins, was also performed. In vivo treatment with PTX into the LC blocked the hypnotic response to LC-administered desmedetomidine and, to a lesser extent, IP-administered dexmedetomidine. The in vivo PTX treatment effectively ribosylated the G proteins. No alteration in the amount of the different species of PTX-sensitive α-subunit was produced by in vivo PTX treatment. These data suggest a pivotal role for PTX-sensitive G proteins in the LC in the hypnotic response to α 2-agonists in the rat.