Hypnosis in palliative care: from clinical insights to the science of self-regulation

Introduction

The growing demand for palliative care represents a challenging medical context for health professionals. On the one hand, clinicians are first and foremost called upon to deliver a reliable medical strategy to manage primary symptoms (1). This line of intervention is qualitatively similar to other medical acts in that it largely rests on the medical skills of practitioners. On the other hand, palliative care often necessitates that medical teams address mental ailments such as psychological distress, acute anxiety, and depression (2). These afflictions impose an extensive burden on the overall wellbeing of patients and their families and therefore require the efficient use of therapeutic interventions (3,4). Integrative medical approaches attempt to harmonize medical and psychological care in an effort to meet such challenges. However, these coordinated interventions represent a complex balancing act where practitioners must consider idiosyncratic factors such as the trajectory of the illness, the medical and psychological history of the patient, their level of social and familial support, as well as their spiritual beliefs (5). These heterogeneous demands force clinicians to intervene at various levels concurrently.

Within the complex context of palliative care, hypnosis represents a substantial adjunct capable of boosting the efficiency of standard treatments (6). In particular, practitioners stand to benefit from using hypnotic interventions to improve clinical outcomes in both medical and psychological treatment. First, a large body of findings validates the efficiency of hypnotic interventions in the management of pain and physical discomfort (7-9). Hypnosis can reduce drug intake in pharmacological treatments and abate unpleasant side effects. Moreover, hypnosis represents a well-established add-on for enhancing the efficiency of psychotherapy intended to alleviate psychological distress, acute anxiety disorder, and depression (10-16). However, despite its potency and empirical grounding, clinical hypnosis remains largely underutilized in palliative care, likely as a consequence of largely misinformed views amongst medical practitioners. Beset by a history of charlatanism and folktales, hypnosis has yet to (re)gain prominence in mainstream medical and psychological practices, especially in comparison to the growing prevalence of contemplative practices (17). Here, we propose to tackle this enduring skepticism by cataloging some of the core psychological mechanisms that characterize the hypnotic response and by highlighting key empirical findings that inform our view. In this fashion, we hope to placate lingering doubts about the merits of hypnotic interventions in palliative care.

Our goals are twofold: first, to provide a reliable framework for understanding some of the core components of hypnosis, thereby informing prevailing models of hypnotic interventions in palliative medicine; second, to set the foundation for building bridges between intuitive clinical knowledge and scientific views of hypnosis. This second objective pertains to the particular issue of translating fundamental discoveries in the science of hypnosis into evidence-based clinical practices (12). While the gap between clinical and empirical knowledge impacts most of medicine (18), we sketch out how this hurdle represents a primary issue for the adoption of hypnosis as a favorable medical intervention. Our framework addresses this concern by closing the gap between prevailing clinical insights and the science of self-regulation.

The gap between clinical practice and fundamental research

Evidence-based medicine calls for health officials and medical practitioners to turn reliable medical findings into clinical practice (19). However, this endeavor presents many challenges (20). Hypnosis is no stranger to these challenges.

Scientists exploring hypnotic phenomena have mainly geared their efforts towards understanding the influence of inter-individual differences in hypnotic susceptibility, the role of the hypnotic induction, and the effects of hypnosis and post-hypnotic suggestions (21-24). This research is constantly spurring groundbreaking discoveries and innovative hypotheses (25), leading to new and insightful approaches for clinical interventions (26,27). And yet, various challenges remain in translating this research into safe and efficient practices. One such challenge concerns the near-absence of a strong, coherent, theoretical foundation of hypnosis (25,28,29). While experts largely subscribe to the idea that hypnotic phenomena involve the ability to produce a behavioral or mental response following a suggestion (30-32), theoretical debates about the nature of hypnosis have divided the field for more than 2 decades (33-36). These quarrels have predominantly centered on whether hypnosis represents an “altered state of consciousness”. Some theories emphasize the role of phenomenology in generating reliable hypnotic responses (37), while others challenge this view (38). Yet others advocate for a more pragmatic scientific approach that would transcend these controversies and instead focus on the underlying mechanisms that enable the emergence of hypnotic phenomena (39,40). Consistent with this view, we plan to adopt this epistemic strategy and translate fundamental research into reliable clinical practice by underlining some of the mechanisms inherent to hypnotic response.

Scientific and applied approaches to hypnosis highlight philosophical differences between scientific and clinical methods. The structure of the scientific method requires researchers to adopt a standardized approach to hypnosis that is hardly customizable to inter-individual differences. In contrast, health professionals strive to adjust their strategies to the specificity of their patients and the therapeutic context (29,41). This disparity introduces a tension between the desire to develop a science that generalizes to an entire population and the need to develop personalized therapeutic tools adaptable to single cases. While this issue permeates the clinical realm as a whole, it remains particularly pervasive in the case of hypnosis where individuals are capable of using a wide variety of mental strategies to generate the hypnotic response (31,42,43). Hence, the rigor imposed by the scientific method does not correspond to the adaptability of clinical approaches. To be sure, clinicians using hypnosis often develop strong intuitions about ways to tweak their interventions in order to facilitate the process. These clinical insights mainly reflect the development of expertise for recognizing the emergence of certain response patterns and adjusting their intervention accordingly (44,45). How can we develop a science of hypnosis that properly accounts for such clinical skills? We propose to address this difficulty by emphasizing some of the core principles that typify a reliable hypnotic response. Highlighting these components can provide health care professionals with valid guidelines and afford them with sufficient flexibility to tailor interventions to specific patients and contexts.

The science of hypnosis

In order to underline the central aspects of hypnosis, we must first situate them within the more general domain of the hypnotic procedure. The ritual of hypnosis typically involves two phases: induction and suggestion. The induction process includes a set of instructions intended to evoke a state of heightened attention and increased response preparation (46,47). Individuals undergoing hypnosis typically become mentally absorbed towards a certain mental object, and produce reliable responses to instructions (48-50). 
Distinct neural patterns involving the modulation of top-down control systems accompany this procedure (51-53). Suggestions form communicable representations—most often verbal—capable of prompting a mental or behavioral response (30). In particular, the hypnotic operator employs hypnotic and post-hypnotic suggestions to target specific perceptual, cognitive, emotional, or ideomotor processes (21,31,54). Evidence shows the centrality of suggestions in generating a reliable response (22,55-57). Together, induction and suggestion form an established procedure that offers clinicians the flexibility to customize: induction can maximize mental absorption, response preparation, and relaxation whereas suggestions generate a steadfast response. As a case in point, such bespoke customizations can come about as a function of authoritarian suggestions, as opposed to permissive ones (29). Clinicians practicing hypnosis must therefore determine the best adjustments to achieve the desired therapeutic and medical objectives.

Some scholars regard induction and suggestion as procedures on distinct conceptual planes (Barabasz & Barabasz, 2016) (58). For example, certain theories postulate that the induction yields an altered state of consciousness and the emergence of hypnotic phenomena (59). However, different arguments undermine the notion that induction and suggestions are conceptually distinct (60). First, both induction and suggestion rely on instructions that solely differ in content relative to their respective timing and purpose (61). Instructions during induction precede those of the suggestion phase and aim to enhance mental absorption and response preparation, while instructions of the suggestion phase ought to generate a specific hypnotic response. Second, various empirical findings highlight the prominent role of suggestions in producing the hypnotic response while downplaying the importance of hypnotic trance (22,56,57,62). Yet, dismissing the induction procedure altogether seems premature (46). The framework we are proposing posits that the induction and suggestion procedures represent different stages of the hypnosis process, each being largely defined by their respective objectives.

Five fundamental principles of hypnosis: Implications for palliative care

Equifinality

The principle of equifinality, which applies to hypnotic phenomena, states that different means can lead to the same end state. In other words, distinct cognitive strategies may lead individuals to achieve similar hypnotic responses (42). Supporting this view, mounting evidence highlights heterogeneity amongst individuals who are highly susceptible to hypnosis, thereby implying that reliable hypnotic responses may occur through several cognitive and phenomenological profiles (63-66). Evidence highlights how this heterogeneity cuts across several domains including cognitive strategies (67), cognitive functioning (65), and phenomenology (68). Compounded, these findings intimate that equifinality represents a central aspect of hypnosis, whereby different cognitive routes can produce similar hypnotic responses.

Brain-imaging experiments provide further evidence for equifinality. For example, comparing the modulation of pain in fibromyalgia with experimentally induced pain, a recent study unveiled similar effects at the subjective level, yet distinct neural patterns (69). In this experiment, individuals with fibromyalgia and controls received nociceptive stimulation alongside the same suggestion for regulating their subjective experience of pain. While both groups adjusted their subjective experience in a similar fashion, neuroimaging data show that they achieved it through different means. These findings extend previous work (70-75) showing that the hypnotic modulation of pain perception spans distinct neural pathways. Furthermore, the results show that context seems important in determining response, as the source of the experienced pain (fibromyalgia versus experimentally induced) led to different neural outcomes.

Support for equifinality also comes from cognitive neuroscience. For example, individuals can uniformly reduce pain, irrespective of whether they employ relaxation or de-personalization strategies (76). In the same vein, findings also highlight how direct or indirect hypnotic suggestions can achieve comparable outcomes by recruiting separate brain networks (77). Thus, evidence corroborates the notion that different cognitive strategies during hypnotic suggestions can converge on a single end state.

As a particular feature of hypnosis, equifinality allows healthcare professionals to customize their approach depending on the strategies that work best for the patient. Unlike pure scientists, practitioners must exercise substantial flexibility when they fashion their clinical approach. Given that hypnosis is so adaptable to the individual, one may argue that different “keys” are capable of “unlocking” a hypnotic response depending on the particular abilities and needs of the patient (41). In the context of palliative care, the characteristics, needs, and abilities of patients can vary tremendously—a challenge for rigid therapeutic and medical interventions (78). Equifinality affords hypnotic practitioners of palliative care with degrees of freedom, allowing them to explore different hypnotic strategies. Even when patients do have the same end goal, the hypnotic operator can structure hypnotic suggestions depending on the specific hypnotic abilities of the patient to achieve maximum benefit. These clinical interventions should notably take into account the specific context and the objectives of their patients and relies, at least in part, on the creativity and resourcefulness of the health care professional to achieve these goals (79). To attain these goals clinicians need to establish a strong therapeutic bond by pacing the process, welcoming and appreciating their difficulties, and leading them towards novel experiences relative to the health challenge they are currently facing.

Response preparation as a key predictor of hypnotic response

Expectations fundamentally shape our experience of the world (80-89), and this wide-ranging influence encompasses hypnotic phenomena where expectations influence the quality of hypnotic responses (40). We can observe this overarching influence across several dimensions. Evidence shows how preparing participants, by either using hypnosis-related terminology or providing information about hypnosis, enhances hypnotic susceptibility (90,91). This key finding likely hinges on sociocultural expectations, where individuals anticipate that hypnosis will trigger profound changes in conscious experience, leading them to respond in concordance with such expectations (46). Thus, when an individual anticipates hypnosis, they are preparing to respond based on their prior beliefs, knowledge, and expectations (35,38,82,83,92,93). Clinicians ought to mobilize this principle by establishing a hypnotic context that maximizes the therapeutic outcome. During the intervention, response preparation therefore requires that health professionals inform patients about hypnosis and define their personal objectives within this particular clinical context. Informing patient is critical for increased collaboration and managing anticipation.

Some argue that the influence of expectation stems from some sort of attitude towards hypnosis (94,95). Contrary to hypnotic aptitude, which corresponds to a largely stable trait for producing reliable hypnotic responses (21,96,97), attitude relies on social-cognitive factors, including motivation, role enactment, beliefs, and expectations (35). Empirical findings corroborate the importance of attitude and response preparation for producing a reliable hypnotic response (94). Moreover, neuroimaging research with hypnosis and functional pain shows that activity in the executive network during the initial suggestion of pain predicts the subsequent quality of the hypnotic response, both at the subjective and neural levels (98). In this way, the executive network putatively plays a key role in the production of a response by allowing hypnotized individuals to develop an efficient mental strategy (21). Overall, this body of evidence emphasizes the importance of good response preparation. Thus, clinicians should enhance treatment efficacy by adequately preparing the hypnotic context. Because effects likely hinge on factors such as motivation, confidence, and desperation, constructing positive expectations—for example, through suggestions and reinforcement feedback—becomes key (29,99).

Mental imagery and the hypnotic response

Mental imagery refers to the generation of endogenous mental representations that share essential components with perceptual experiences (100-102). Due to their proximity with actual perception processing, these representations may even induce similar effects to sensory processing (103). In the context of hypnosis, an operator will often capitalize on this mental capacity to achieve certain objectives throughout the ritual (29,79). During the induction procedure, imagery can serve as a valuable target for guiding and enhancing mental absorption (79,104). For example, to deepen the state of absorption, the operator may ask an individual undergoing hypnosis to imagine walking down a staircase. During the suggestion phase, the operator may similarly use imagery to provide individuals with an efficient strategy to improve their responses.

Evidence notably confirms that mental visualization represents powerful mechanism for regulating pain (105-109). A recent study looked at how the content of mental imagery can serve a reliable strategy to regulate nociceptive processing (107). This study demonstrates how strategies for visual imagery—either a ‘glove covering the forearm’ or a ‘wound’—can modulate pain perception, the threshold at which pain is experienced, and pain-related cortical responses. More specifically, these results highlight that employing opposite strategies can similarly impact perceptual processing of the nociceptive signal, while leading to contrasting effects on the threshold of pain perception. Hence, visual imagery does not serve as a mere distraction from pain but rather has a direct influence on sensory, cognitive, and affective experience along with corresponding brain activity. While visualization alone is enough to regulate pain experience, effect sizes are larger in a hypnotic context (106) and there are endless possibilities for including visual imagery in hypnotic suggestions for pain management (9). Moreover, mental images may contribute to the development of one’s ability to use hypnosis by allowing clinicians to tailor their suggestions relative to the objectives of palliative care.

While some experts downplay the role of imagination in hypnosis (47), its importance has been long acknowledged (110,111). However, hypnotic phenomena hardly reduce to mental imagery (106,112-114). In our view, distinguishing hypnosis from imagery is consistent with the idea that hypnosis is multifaceted, and therefore encompasses several dimensions beyond imagery. Consistent with this view, a closer look at the evidence does reveal a certain amount of overlap between mere imagery and hypnosis (56,113,115-117). In addition, a recent meta-analytic review of neuroimaging studies revealed that hypnosis correlated most robustly with lingual gyrus activation, a brain region strongly linked with mental imagery (Landry et al., 2017) (21). According to these findings, neural activation of visual areas is the singular most consistent finding in current neuroimaging studies—seemingly a core component of the hypnotic response.

Regulation of automatic processes

One striking feature of hypnosis is that hypnotic suggestions can regulate automatic cognitive processes (118). Cognitive scientists tend to operationally group mental processes into either “controlled” or “automatic”, where controlled processes are effortful, intentional, and slow, and automatic processes are unintentional, involuntary and engrained (119,120). A large body of evidence demonstrates the capacity of individuals, who are highly susceptible to hypnosis, to modulate automatic processes following hypnotic suggestions (95,118,121-128). A benchmark experiment illustrating this capacity showcases reduction in the Stroop effect (121). During the Stroop task, participants see names of colors printed in various ink colors (e.g., the word “red” printed in blue ink). This experimental context requires that participants indicate the printed color and typically results in congruency effects, whereby an incongruent name and text color negatively impacts performance compared to when they are congruent due to the automaticity of reading for literate individuals (129). By exhibiting how hypnosis may reduce congruency effects in the Stroop task, this evidence indicates that individuals are capable of using efficient mental strategies for regulating mental processes heretofore considered resistant to cognitive control (43).

The possibility of derailing automatic processes affords ample applications for clinical intervention. Practitioners can notably use this inherent aspect of hypnosis as a tool to target engrained thought patterns and maladaptive behaviors that have become highly automatized, such as rumination. Viewed as a form of pathological self-reflection, rumination is characterized by compulsive thoughts about distress, repeatedly cluttering the mind with unwanted cognitions (130). Prevailing theories purport that rumination is a response to unresolved goals due to discrepancies between reality and aspirations. In palliative care, an individual must confront the psychosocial, existential, and physical aspects of the dying experience and thus often face a gap between the reality of their life and their aspirations. Indeed, patients in end-of-life care report significantly higher levels of rumination than age-matched controls (131,132). Moreover, rumination forms the onset and maintenance of psychological distress, and is completely treatable (133). Practitioners in the palliative context can harness the capacity of hypnotic suggestion to specifically target and derail negative automatic processes, such as those implicated in rumination. In this fashion, by containing the ballistic spiral of a detrimental cognitive cascade, hypnosis can lead to better psychological well-being.

Precision of the hypnotic response

Hypnosis can selectively target precise mental processes, leading to focal outcomes (31,134). In other words, the content of a suggestion can lead individuals to achieve a variety of very precise hypnotic responses, as a function of the desired outcome. Empirical evidence demonstrates this precision across many sensory domains (56,70,71,135,136), cognitive processes (125,137), and ideomotor processing (115) These findings demonstrate that response precision is a core feature of hypnosis; suggestions can lead to great specificity (138).

Hypnotic suggestions with visual context leads to subsequent activity in the visual cortex (56), while hypnosis can selectively target the anterior cingulate cortex (ACC) or the somatosensory cortex depending on the content of the suggestion (70). In a series of seminal papers, Rainville et al., utilized hypnosis to selectively modulate sensory and affective components of the pain response, along with the corresponding neural correlates. Specifically, their findings demonstrate that hypnosis can target subjective ratings of pain unpleasantness and associated pain-related activity in limbic regions without changing the perceived intensity of the pain or neural activation of the somatosensory cortex (70,139). These findings demonstrate the extreme precision of the hypnotic response, whereby suggestion can target specific brain areas while leaving others untouched.

Because hypnosis has the potential to dissociate between subjective and sensory experience, it holds powerful clinical applications for palliative care. While the peripheral pain that accompanies terminal illness is inevitable, hypnosis can effectively contain the affective component of pain. Moreover, in palliative medicine concerns span specific domains including side effects, localized pain, but more dominantly existential anxiety and spiritual distress (140,141) which often morphs into affective anxiety (142). Hypnosis can specifically target affectivity and modulate neural activity in the ACC (70). Clinicians can harness this specificity of the hypnotic response to selectively target the strong affective component of near-death anxiety, reducing intense somatic activation in order for psychotherapy to take place. By reducing emotional anxiety, a clinician can facilitate the processing of traumatic experiences (143). Given the variety and specificity of patient needs, the precision of hypnosis renders it a useful adjunct in the clinical armamentarium of the palliative practitioner. Moreover, hypnosis is a single tool that can address a multitude of concerns spanning the psychological, medical, and spiritual needs of the patient.

Conclusions

In this paper we sketch out a framework for integrating the science of hypnosis into the palliative context. A gap between scientific data and clinical application presents a general challenge; this lacuna is especially prominent in the realm of hypnosis where data are strong and applications are sparse. For example, ample evidence supports the efficacy of hypnosis in pain management and could provide great benefit in a palliative context where patients experience severe, debilitating pain (6,7,9).

Here we show five fundamental scientific findings from hypnosis research while demonstrating how these inherent components of hypnotic phenomena lend themselves to palliative care. With a growing older population and a pressing need for innovative palliative interventions, demand for end-of-life care is on the rise. With mind-body therapies becoming more prevalent on the spectrum of palliative offerings, we submit hypnosis as a powerful adjunctive therapy to support medical, psychological, and spiritual well-being.

Acknowledgements

M Landry acknowledges an Alexander Graham Bell Canada Graduate Scholarship from the Natural Sciences and Engineering Research Council of Canada (NSERC); M Stendel acknowledges a Graduate Scholarship from the Social Sciences and Humanities Research Concil (SSHRC); A Raz acknowledges funding from the Discovery and Discovery Acceleration Supplement grants from NSERC, the BIAL Foundation, and the Canadian Institutes of Health Research.

Footnote

Conflicts of Interest: The authors have no conflicts of interest to declare.

References

1. Lorenz KA, Lynn J, Dy SM, et al. Evidence for improving palliative care at the end of life: a systematic review. Ann Intern Med 2008;148:147-59. [Crossref] [PubMed]
2. Barraclough J. ABC of palliative care. Depression, anxiety, and confusion. BMJ 1997;315:1365-8. [Crossref] [PubMed]
3. Chochinov HM. Dying, Dignity, and New Horizons in Palliative End-of-Life Care. CA Cancer J Clin 2006;56:84-103. [Crossref] [PubMed]
4. Chochinov HM, Hack T, Hassard T, et al. Dignity and psychotherapeutic considerations in end-of-life care. J Palliat Care 2004;20:134-42. [PubMed]
5. Kelley AS, Morrison RS. Palliative care for the seriously ill. N Engl J Med 2015;373:747-55. [Crossref] [PubMed]
6. Brugnoli MP. Clinical hypnosis for palliative care in severe chronic diseases: a review and the procedures for relieving physical, psychological and spiritual symptoms. Ann Palliat Med 2016;5:280-97. [Crossref] [PubMed]
7. Patterson DR, Jensen MP. Hypnosis and clinical pain. Psychol Bull 2003;129:495-521. [Crossref] [PubMed]
8. Jensen M, Patterson DR. Hypnotic treatment of chronic pain. J Behav Med 2006;29:95-124. [Crossref] [PubMed]
9. Jensen MP, Patterson DR. Hypnotic approaches for chronic pain management: Clinical implications of recent research findings. Am Psychol 2014;69:167-77. [Crossref] [PubMed]
10. Alladin A. Cognitive hypnotherapy for treating depression. In: Chapman R. editor. The Clinical Use of Hypnosis with Cognitive Behavior Therapy: A Practitioner’s Casebook. New York: Springer, 2006.
11. Alladin A. Handbook of Cognitive Hypnotherapy for Depression: An Evidence-based Approach. Philadelphia: Lippincott Williams & Wilkins, 2007.
12. Alladin A, Sabatini L, Amundson JK. What should we mean by empirical validation in hypnotherapy: Evidence-based practice in clinical hypnosis. Int J Clin Exp Hypn 2007;55:115-30. [Crossref] [PubMed]
13. Alladin A. Cognitive Hypnotherapy: An Integrated Approach to the Treatment of Emotional Disorders. Chichester: John Wiley & Sons, 2008.
14. Alladin A. Evidence-based cognitive hypnotherapy for depression. Contemp Hypn 2009;26:245-62. [Crossref]
15. Alladin A. Cognitive hypnotherapy: A new vision and strategy for research and practice. Am J Clin Hypn 2012;54:249-62. [Crossref] [PubMed]
16. Alladin A. Cognitive hypnotherapy for major depressive disorder. Am J Clin Hypn 2012;54:275-93. [Crossref] [PubMed]
17. Raz A, Lifshitz M. Hypnosis and meditation: Towards an integrative science of conscious planes. Oxford: Oxford University Press, 2016.
18. Lenfant C. Clinical research to clinical practice—lost in translation? N Engl J Med 2003;349:868-74. [Crossref] [PubMed]
19. Sackett DL, Rosenberg WM, Gray JA, et al. Evidence based medicine: what it is and what it isn't. BMJ 1996;312:71-2. [Crossref] [PubMed]
20. Glasgow RE, Emmons KM. How can we increase translation of research into practice? Types of evidence needed. Annu Rev Public Health 2007;28:413-33. [Crossref] [PubMed]
21. Landry M, Lifshitz M, Raz A. Brain correlates of hypnosis: A systematic review and meta-analytic exploration. Neurosci Biobehav Rev 2017;81:75-98. [Crossref] [PubMed]
22. Mazzoni G, Rotriquenz E, Carvalho C, et al. Suggested visual hallucinations in and out of hypnosis. Conscious Cogn 2009;18:494-9. [Crossref] [PubMed]
23. Oakley DA, Halligan PW. Hypnotic suggestion and cognitive neuroscience. Trends Cogn Sci 2009;13:264-70. [Crossref] [PubMed]
24. Oakley DA, Halligan PW. Hypnotic suggestion: opportunities for cognitive neuroscience. Nat Rev Neurosci 2013;14:565-76. [Crossref] [PubMed]
25. Nash MR, Barnier AJ. The Oxford handbook of hypnosis: theory, research and practice. New York: Oxford University Press, 2008.
26. Elkins G. Clinician's Guide to Medical and Psychological Hypnosis: Foundations, Applications, and Professional Issues. New York: Springer Publishing Company, 2016.
27. Lynn SJ, Rhue JW, Kirsch I. Handbook of clinical hypnosis. Washington: American Psychological Association, 2010.
28. Jamieson GA. Hypnosis and conscious states: The cognitive neuroscience perspective. New York: Oxford University Press, 2007.
29. Yapko MD. Essentials of hypnosis. 2nd ed. New York: Routledge, 2015.
30. Halligan PW, Oakley DA. Hypnosis and beyond: Exploring the broader domain of suggestion. Psychology of Consciousness: Theory, Research, and Practice 2014;1:105-22. [Crossref]
31. Landry M, Raz A. Hypnosis and imaging of the living brain. Am J Clin Hypn 2015;57:285-313. [Crossref] [PubMed]
32. Michael RB, Garry M, Kirsch I. Suggestion, cognition, and behavior. Curr Dir Psychol Sci 2012;21:151-6. [Crossref]
33. Barnier AJ, Dienes Z, Mitchell CJ. How hypnosis happens: New cognitive theories of hypnotic responding. In: Nash MR, Barnier AJ. editors. The Oxford handbook of hypnosis: Theory, research and practice. Oxford: Oxford University Press, 2008:141-78.
34. Cardeña E, Spiegel D. Suggestibility, absorption, and dissociation: An integrative model of hypnosis. Human suggestibility: Advances in theory, research, and application. Florence: Taylor & Frances/Routledge, 1991:93-107.
35. Lynn SJ, Kirsch I, Hallquist MN. Social cognitive theories of hypnosis. In: Nash MR, Barnier AJ. editors. The Oxford handbook of hypnosis: Theory, research and practice. Oxford: Oxford University Press, 2008:111-39.
36. Kihlstrom JF. The domain of hypnosis, revisited. In: Nash MR, Barnier AJ. editors. The Oxford handbook of hypnosis: theory, research and practice. Oxford: Oxford University Press, 2008.
37. Kallio S, Revonsuo A. Hypnotic phenomena and altered states of consciousness: a multilevel framework of description and explanation. Contemp Hypn 2003;20:111-64. [Crossref]
38. Kirsch I, Lynn SJ. Social–cognitive alternatives to dissociation theories of hypnotic involuntariness. Rev Gen Psychol 1998;2:66-80. [Crossref]
39. Jensen MP, Jamieson GA, Lutz A, et al. New directions in hypnosis research: strategies for advancing the cognitive and clinical neuroscience of hypnosis. Neurosci Conscious 2017;3:nix004. [PubMed]
40. Terhune DB, Cleeremans A, Raz A, et al. Hypnosis and top-down regulation of consciousness. Neurosci Biobehav Rev 2017;81:59-74. [Crossref] [PubMed]
41. Barber J. The locksmith model: Accessing hypnotic responsiveness. In: Lynn SJ, Rhue JW. editors. Theories of hypnosis: Current models and perspectives. New York: Guilford, 1991.
42. Cardeña E. Hypnos and psyche: How hypnosis has contributed to the study of consciousness. Psychology of Consciousness: Theory, Research, and Practice 2014;1:123-38. [Crossref]
43. Egner T, Raz A. Cognitive Control Processes and Hypnosis. In: Jamieson GA. editor. Hypnosis and Conscious States: The cognitive neuroscience perspective. New York: Oxford University Press, 2007:29-50.
44. Bates BL. Individual differences in response to hypnosis. In: Rhue JW, Lynn SJ, Kirsch I. editors. Handbook of clinical hypnosis. Washington: American Psychological Association, 1993:23-54.
45. Strauss BS. Operator variables in hypnotherapy. In: Rhue JW, Lynn SJ, Kirsch I. editors. Handbook of clinical hypnosis. Washington: American Psychological Association, 1993:55-72.
46. Terhune DB, Cardeña E. Nuances and Uncertainties Regarding Hypnotic Inductions: Toward a Theoretically Informed Praxis. Am J Clin Hypn 2016;59:155-74. [Crossref] [PubMed]
47. Woody E, Sadler P. What Can a Hypnotic Induction Do? Am J Clin Hypn 2016;59:138-54. [Crossref] [PubMed]
48. Maldonado JR, Spiegel D. Hypnosis. Psychiatry. Chichester: John Wiley & Sons, Ltd, 2008:1982-2026.
49. Rainville P, Hofbauer RK, Bushnell MC, et al. Hypnosis modulates activity in brain structures involved in the regulation of consciousness. J Cogn Neurosci 2002;14:887-901. [Crossref] [PubMed]
50. Rainville P, Price DD. Hypnosis phenomenology and the neurobiology of consciousness. Int J Clin Exp Hypn 2003;51:105-29. [Crossref] [PubMed]
51. Jamieson GA, Burgess AP. Hypnotic induction is followed by state-like changes in the organization of EEG functional connectivity in the theta and beta frequency bands in high-hypnotically susceptible individuals. Front Hum Neurosci 2014;8:528. [Crossref] [PubMed]
52. Jiang H, White MP, Greicius MD, et al. Brain Activity and Functional Connectivity Associated with Hypnosis. Cerebral Cortex 2017;27:4083-93. [PubMed]
53. Rainville P, Hofbauer RK, Paus T, et al. Cerebral mechanisms of hypnotic induction and suggestion. J Cogn Neurosci 1999;11:110-25. [Crossref] [PubMed]
54. Landry M, Raz A. Neurophysiology of hypnosis. In: Elkins G. editor. The Clinician’s Guide to Medical and Psychological Hypnosis: Foundations, Systems, Applications and Professional Issues. New York: Springer-Verlag New York, 2016.
55. Mazzoni G, Venneri A, McGeown WJ, et al. Neuroimaging resolution of the altered state hypothesis. Cortex 2013;49:400-10. [Crossref] [PubMed]
56. McGeown WJ, Venneri A, Kirsch I, et al. Suggested visual hallucination without hypnosis enhances activity in visual areas of the brain. Conscious Cogn 2012;21:100-16. [Crossref] [PubMed]
57. Raz A, Kirsch I, Pollard J, et al. Suggestion reduces the Stroop effect. Psychol Sci 2006;17:91-5. [Crossref] [PubMed]
58. Barabasz A, Barabasz M. Induction Technique: Beyond Simple Response to Suggestion. Am J Clin Hypn 2016;59:204-13. [Crossref] [PubMed]
59. Lankton S. A SoC Model of Hypnosis and Induction. Am J Clin Hypn 2015;57:367-77. [Crossref] [PubMed]
60. Lynn SJ, Maxwell R, Green JP. The Hypnotic Induction in the Broad Scheme of Hypnosis: A Sociocognitive Perspective. Am J Clin Hypn 2017;59:363-84. [Crossref] [PubMed]
61. Nash MR. The importance of being earnest when crafting definitions: Science and scientism are not the same thing. Int J Clin Exp Hypn 2005;53:265-80. [Crossref] [PubMed]
62. Braffman W, Kirsch I. Imaginative suggestibility and hypnotizability: an empirical analysis. J Pers Soc Psychol 1999;77:578-87. [Crossref] [PubMed]
63. McConkey KM, Barnier AJ. High hypnotisability: unity and diversity in behaviour and experience. In: Heap M, Brown RJ, Oakley DA. editors. The highly hypnotizable person: Theoretical, experimental and clinical issues. New York: Routledge, 2004:61-84.
64. Terhune DB. Discrete response patterns in the upper range of hypnotic suggestibility: A latent profile analysis. Conscious Cogn 2015;33:334-41. [Crossref] [PubMed]
65. Terhune DB, Cardeña E, Lindgren M. Dissociated control as a signature of typological variability in high hypnotic suggestibility. Conscious Cogn 2011;20:727-36. [Crossref] [PubMed]
66. Terhune DB, Cardeña E, Lindgren M. Dissociative tendencies and individual differences in high hypnotic suggestibility. Cogn Neuropsychiatry 2011;16:113-35. [Crossref] [PubMed]
67. Galea V, Woody EZ, Szechtman H, et al. Motion in response to the hypnotic suggestion of arm rigidity: A window on underlying mechanisms. Int J Clin Exp Hypn 2010;58:251-68. [Crossref] [PubMed]
68. Terhune DB, Polito V, Barnier AJ, et al. Variations in the sense of agency during hypnotic responding: Insights from latent profile analysis. Psychology of Consciousness: Theory, Research, and Practice 2016;3:293-302. [Crossref]
69. Derbyshire SW, Whalley MG, Seah ST, et al. Suggestions to Reduce Clinical Fibromyalgia Pain and Experimentally Induced Pain Produce Parallel Effects on Perceived Pain but Divergent Functional MRI-Based Brain Activity. Psychosom Med 2017;79:189-200. [PubMed]
70. Rainville P, Duncan GH, Price DD, et al. Pain affect encoded in human anterior cingulate but not somatosensory cortex. Science 1997;277:968-71. [Crossref] [PubMed]
71. Hofbauer RK, Rainville P, Duncan GH, et al. Cortical representation of the sensory dimension of pain. J Neurophysiol 2001;86:402-11. [Crossref] [PubMed]
72. Rainville P, Price DD. The neurophenomenology of hypnosis and hypnotic analgesia. In: Price DD, Bushnell MC. editors. Psychological methods of pain control: Basic science and clinical perspectives. Progress in Pain Research and Management. Seatle: IASP Press, 2004:235-67.
73. Price DD, Rainville P. Hypnotic analgesia. In: Genhart GF, Schmidt RF. editors. Encyclopedia of Pain. Heidelberg New York Dordrecht London: Springer-Verlag Berlin Heidelberg, 2013:1537-42.
74. Wik G, Fischer H, Bragée B, et al. Functional anatomy of hypnotic analgesia: a PET study of patients with fibromyalgia. Eur J Pain 1999;3:7-12. [Crossref] [PubMed]
75. Abrahamsen R, Dietz M, Lodahl S, et al. Effect of hypnotic pain modulation on brain activity in patients with temporomandibular disorder pain. Pain 2010;151:825-33. [Crossref] [PubMed]
76. Röder CH, Michal M, Overbeck G, et al. Pain response in depersonalization: a functional imaging study using hypnosis in healthy subjects. Psychother Psychosom 2007;76:115-21. [Crossref] [PubMed]
77. Nusbaum F, Redouté J, Le Bars D, et al. Chronic low-back pain modulation is enhanced by hypnotic analgesic suggestion by recruiting an emotional network: a PET imaging study. Int J Clin Exp Hypn 2011;59:27-44. [Crossref] [PubMed]
78. Quill TE, Abernethy AP. Generalist plus specialist palliative care—creating a more sustainable model. N Engl J Med 2013;368:1173-5. [Crossref] [PubMed]
79. Hammond DC. Handbook of hypnotic suggestions and metaphors. New York: W.W. Norton & Company, 1990.
80. Clark A. Whatever next? Predictive brains, situated agents, and the future of cognitive science. Behav Brain Sci 2013;36:181-204. [Crossref] [PubMed]
81. Colloca L, Miller FG. Role of expectations in health. Curr Opin Psychiatry 2011;24:149-55. [Crossref] [PubMed]
82. Kirsch I. Response expectancy as a determinant of experience and behavior. Am Psychol 1985;40:1189-202. [Crossref]
83. Kirsch I. Response expectancy theory and application: A decennial review. Appl Prev Psychol 1997;6:69-79. [Crossref]
84. Ploghaus A, Becerra L, Borras C, et al. Neural circuitry underlying pain modulation: expectation, hypnosis, placebo. Trends Cogn Sci 2003;7:197-200. [Crossref] [PubMed]
85. Rao RP, Ballard DH. Predictive coding in the visual cortex: a functional interpretation of some extra-classical receptive-field effects. Nat Neurosci 1999;2:79-87. [Crossref] [PubMed]
86. Rowe JB, Eckstein D, Braver T, et al. How does reward expectation influence cognition in the human brain? J Cogn Neurosci 2008;20:1980-92. [Crossref] [PubMed]
87. Schwarz KA, Pfister R, Büchel C. Rethinking explicit expectations: connecting placebos, social cognition, and contextual perception. Trends Cogn Sci 2016;20:469-80. [Crossref] [PubMed]
88. Summerfield C, Egner T. Expectation (and attention) in visual cognition. Trends Cogn Sci 2009;13:403-9. [Crossref] [PubMed]
89. Summerfield C, de Lange FP. Expectation in perceptual decision making: neural and computational mechanisms. Nat Rev Neurosci 2014;15:745-56. [Crossref] [PubMed]
90. Gandhi B, Oakley DA. Does ‘hypnosis’ by any other name smell as sweet? The efficacy of ‘hypnotic’inductions depends on the label ‘hypnosis’. Conscious Cogn 2005;14:304-15. [Crossref] [PubMed]
91. Hawkins R, Bartsch J. The effects of an educational lecture about hypnosis. AJCEH 2000;28:82-99.
92. Kirsch I. The social learning theory of hypnosis. In: Lynn SJ, Rhue JW. editors. Theories of hypnosis: Current models and perspectives. New York: Guilford Press, 1991.
93. Kirsch I, Wickless C, Moffitt KH. Expectancy and suggestibility: Are the effects of environmental enhancement due to detection? Int J Clin Exp Hypn 1999;47:40-5. [Crossref] [PubMed]
94. Benham G, Woody EZ, Wilson KS, et al. Expect the unexpected: Ability, attitude, and responsiveness to hypnosis. J Pers Soc Psychol 2006;91:342-50. [Crossref] [PubMed]
95. Lifshitz M, Howells C, Raz A. Can expectation enhance response to suggestion? De-automatization illuminates a conundrum. Conscious Cogn 2012;21:1001-8. [Crossref] [PubMed]
96. Piccione C, Hilgard ER, Zimbardo PG. On the degree of stability of measured hypnotizability over a 25-year period. J Pers Soc Psychol 1989;56:289-95. [Crossref] [PubMed]
97. Raz A, Fan J, Posner MI. Neuroimaging and genetic associations of attentional and hypnotic processes. J Physiol Paris 2006;99:483-91. [Crossref] [PubMed]
98. Raij TT, Numminen J, Närvänen S, et al. Strength of prefrontal activation predicts intensity of suggestion-induced pain. Hum Brain Mapp 2009;30:2890-7. [Crossref] [PubMed]
99. Coe WC. Expectations and hypnotherapy. Handbook of clinical hypnosis. Washington: American Psychological Association, 1993:73-93.
100. Kosslyn SM, Ganis G, Thompson WL. Neural foundations of imagery. Nat Rev Neurosci 2001;2:635-42. [Crossref] [PubMed]
101. McNorgan C. A meta-analytic review of multisensory imagery identifies the neural correlates of modality-specific and modality-general imagery. Front Hum Neurosci 2012;6:285. [Crossref] [PubMed]
102. Pearson J, Naselaris T, Holmes EA, et al. Mental imagery: functional mechanisms and clinical applications. Trends Cogn Sci 2015;19:590-602. [Crossref] [PubMed]
103. Allen P, Larøi F, McGuire PK, et al. The hallucinating brain: a review of structural and functional neuroimaging studies of hallucinations. Neurosci Biobehav Rev 2008;32:175-91. [Crossref] [PubMed]
104. Gfeller JD. Enhancing hypnotizability and treatment responsiveness. Handbook of clinical hypnosis. Washington: American Psychological Association, 1993:235-49.
105. Derbyshire SW, Whalley MG, Oakley DA. Fibromyalgia pain and its modulation by hypnotic and non-hypnotic suggestion: An fMRI analysis. Eur J Pain 2009;13:542-50. [Crossref] [PubMed]
106. Derbyshire SW, Whalley MG, Stenger VA, et al. Cerebral activation during hypnotically induced and imagined pain. Neuroimage 2004;23:392-401. [Crossref] [PubMed]
107. Fardo F, Allen M, Jegindø EM, et al. Neurocognitive evidence for mental imagery-driven hypoalgesic and hyperalgesic pain regulation. Neuroimage 2015;120:350-61. [Crossref] [PubMed]
108. MacIver K, Lloyd DM, Kelly S, et al. Phantom limb pain, cortical reorganization and the therapeutic effect of mental imagery. Brain 2008;131:2181-91. [Crossref] [PubMed]
109. Pain Nanay B., Imagery Mental. The Monist 2017;100:485-500. [Crossref]
110. Kirsch I, Braffman W. Imaginative Suggestibility and Hypnotizability. Curr Dir Psychol Sci 2001;10:57-61. [Crossref]
111. Spanos NP. Imagery, hypnosis and hypnotizability. In: Kunzendorf RG. editor. Mental imagery. New York: Springer, 1991:79-88.
112. Hargadon R, Bowers KS, Woody EZ. Does counterpain imagery mediate hypnotic analgesia? J Abnorm Psychol 1995;104:508-16. [Crossref] [PubMed]
113. Müller K, Bacht K, Schramm S, et al. The facilitating effect of clinical hypnosis on motor imagery: An fMRI study. Behav Brain Res 2012;231:164-9. [Crossref] [PubMed]
114. Szechtman H, Woody EZ, Bowers KS, et al. Where the imaginal appears real: a positron emission tomography study of auditory hallucinations. Proc Natl Acad Sci U S A 1998;95:1956-60. [Crossref] [PubMed]
115. Cojan Y, Waber L, Schwartz S, et al. The brain under self-control: modulation of inhibitory and monitoring cortical networks during hypnotic paralysis. Neuron 2009;62:862-75. [Crossref] [PubMed]
116. Ludwig VU, Seitz J, Schönfeldt-Lecuona C, et al. The neural correlates of movement intentions: A pilot study comparing hypnotic and simulated paralysis. Conscious Cogn 2015;35:158-70. [Crossref] [PubMed]
117. Ward NS, Oakley DA, Frackowiak RS, et al. Differential brain activations during intentionally simulated and subjectively experienced paralysis. Cogn Neuropsychiatry 2003;8:295-312. [Crossref] [PubMed]
118. Campbell NK, Blinderman IM, Lifshitz M, et al. Converging evidence for de-automatization as a function of suggestion. Conscious Cogn 2012;21:1579-81. [Crossref] [PubMed]
119. Evans JS, Stanovich KE. Dual-process theories of higher cognition advancing the debate. Perspect Psychol Sci 2013;8:223-41. [Crossref] [PubMed]
120. Schneider W, Shiffrin RM. Controlled and automatic human information processing: I. Detection, search, and attention. Psychol Rev 1977;84:1-66. [Crossref]
121. Raz A, Shapiro T, Fan J, et al. Hypnotic suggestion and the modulation of Stroop interference. Arch Gen Psychiatry 2002;59:1155-61. [Crossref] [PubMed]
122. Raz A, Landzberg KS, Schweizer HR, et al. Posthypnotic suggestion and the modulation of Stroop interference under cycloplegia. Conscious Cogn 2003;12:332-46. [Crossref] [PubMed]
123. Raz A, Fan J, Posner MI. Hypnotic suggestion reduces conflict in the human brain. Proc Natl Acad Sci U S A 2005;102:9978-83. [Crossref] [PubMed]
124. Raz A, Campbell NK. Can suggestion obviate reading? Supplementing primary Stroop evidence with exploratory negative priming analyses. Conscious Cogn 2011;20:312-20. [Crossref] [PubMed]
125. Lifshitz M, Aubert Bonn N, Fischer A, et al. Using suggestion to modulate automatic processes: from Stroop to McGurk and beyond. Cortex 2013;49:463-73. [Crossref] [PubMed]
126. Augustinova M, Ferrand L. Suggestion does not de-automatize word reading: evidence from the semantically based Stroop task. Psychon Bull Rev 2012;19:521-7. [Crossref] [PubMed]
127. Augustinova M, Ferrand L. Automaticity of Word Reading Evidence From the Semantic Stroop Paradigm. Curr Dir Psychol Sci 2014;23:343-8. [Crossref]
128. Iani C, Ricci F, Gherri E, et al. Hypnotic suggestion modulates cognitive conflict: the case of the flanker compatibility effect. Psychol Sci 2006;17:721-7. [Crossref] [PubMed]
129. MacLeod CM. Half a century of research on the Stroop effect: an integrative review. Psychol Bull 1991;109:163-203. [Crossref] [PubMed]
130. Nolen-Hoeksema S, Wisco BE, Lyubomirsky S. Rethinking rumination. Perspect Psychol Sci 2008;3:400-24. [Crossref] [PubMed]
131. Galfin JM, Watkins ER, Harlow T. Psychological distress and rumination in palliative care patients and their caregivers. J Palliat Med 2010;13:1345-8. [Crossref] [PubMed]
132. Galfin JM, Watkins ER. Construal level, rumination, and psychological distress in palliative care. Psychooncology 2012;21:680-3. [Crossref] [PubMed]
133. Nolen-Hoeksema S. The role of rumination in depressive disorders and mixed anxiety/depressive symptoms. J Abnorm Psychol 2000;109:504-11. [Crossref] [PubMed]
134. Landry M, Appourchaux K, Raz A. Elucidating Unconscious Processing With Instrumental Hypnosis. Front Psychol 2014;5:785. [Crossref] [PubMed]
135. Koivisto M, Kirjanen S, Revonsuo A, et al. A preconscious neural mechanism of hypnotically altered colors: a double case study. PLoS one 2013;8:e70900. [Crossref] [PubMed]
136. Kosslyn SM, Thompson WL, Costantini-Ferrando MF, et al. Hypnotic visual illusion alters color processing in the brain. Am J Psychiatry 2000;157:1279-84. [Crossref] [PubMed]
137. Mendelsohn A, Chalamish Y, Solomonovich A, et al. Mesmerizing memories: brain substrates of episodic memory suppression in posthypnotic amnesia. Neuron 2008;57:159-70. [Crossref] [PubMed]
138. Raz A, Michels R. Contextualizing specificity: Specific and non-specific effects of treatment. Am J Clin Hypn 2007;50:177-82. [Crossref] [PubMed]
139. Rainville P, Carrier B, Hofbauer RK, et al. Dissociation of sensory and affective dimensions of pain using hypnotic modulation. Pain 1999;82:159-71. [Crossref] [PubMed]
140. Boston P, Bruce A, Schreiber R. Existential suffering in the palliative care setting: an integrated literature review. J Pain Symptom Manage 2011;41:604-18. [Crossref] [PubMed]
141. Schuman-Olivier Z, Brendel DH, Forstein M, et al. The use of palliative sedation for existential distress: a psychiatric perspective. Harv Rev Psychiatry 2008;16:339-51. [Crossref] [PubMed]
142. LeMay K, Wilson KG. Treatment of existential distress in life threatening illness: a review of manualized interventions. Clin Psychol Rev 2008;28:472-93. [Crossref] [PubMed]
143. Oehen P, Traber R, Widmer V, et al. A randomized, controlled pilot study of MDMA (± 3,4-Methylenedioxymethamphetamine)-assisted psychotherapy for treatment of resistant, chronic Post-Traumatic Stress Disorder (PTSD). J Psychopharmacol 2013;27:40-52. [Crossref] [PubMed]