Why are some people more hypnotisable than others?

If you ask someone about their experience receiving hypnotherapy, you may get a mixture of reviews. Some share life-changing moments, some may have needed more sessions than others, whereas others may simply shrug and say that it wasn’t their cup of tea. Why is this the case?

There are a range of things that could influence the success of a hypnotherapy session: the willpower of the client, the complexity of the task, the rapport that the client has with their hypnotherapist as well as the skills of the hypnotherapists themselves. Whilst this is all true, it doesn’t help much to explain why one hypnotherapist may still get varied results from their clients. Some people are simply more responsive to hypnosis than others.

Most people have a capacity to benefit from hypnotherapy. There are those who are more hypnotisable and may respond faster to hypnosis or have a stronger positive reaction from their intervention than those who are less hypnotisable (e.g., Patterson & Pacek, 1997). What exactly does this mean? The term hypnotisability refers to “an individual’s ability to experience suggested alterations in physiology, sensations, emotions, thoughts or behaviour during hypnosis” (Elkins et al., 2015). Most people fall into the upper-middle of the global scale of hypnotisability, with some individuals falling on either end of the curve, being either highly hypnotisable or barely at all (Elkins, 2014).

Throughout the world of research, the titular question is something that regularly surfaces on subjects about hypnotherapy. There are a several recognised tests to find out how hypnotisable someone is, such as the often-used Stanford Scales, and it is generally agreed upon that the higher someone’s level of hypnotisability, the more benefits they could stand to gain from hypnosis. As of yet, there is not, one clear answer to what influences this, but as technology advances, the picture is slowly becoming clearer.

One thing we do know is that a person’s level of hypnotisability generally appears to be stable over time (Piccione, Hilgard & Zimbardo, 1989). This stability gives us clues that at least part of what influences how hypnotisable we are is coded within us, be it our brain, our genes, or something else.

Early data on genetics and hypnotisability was admittedly somewhat limited. All that arose in the 70s and 80s were twin studies on heritability, although they were inciteful. Piccione, Hilgard & Zimbardo (1989) claimed that twin studies highlighted that hypnotisability was around 44-64% heritable, depending on age and ethnicity.

Things would change with the human genome project that ran through the end of the 20^th Century and unlocked a new world of information, facilitating an influx of new findings. One of these discoveries was the COMT gene and its mutations.

Spanning across 1999 to 2017, there has been a lot of investigation into catechol-O-methyltransferase (COMT) by various research groups (Lichtenberg et al., 2004; Raz, 2005; Szekely et al., 2010). This gene is linked to the reward pathways in our brain, and mutations in this gene change which enzymes are produced to break down dopamine. Changes in the COMT gene seem to cause a production of two different alleles: valine or methionine. The first findings claimed that production of valine was most often linked to high hypnotisability scores, and methionine with low scores. Szekely et al., (2017) argue that valine is more efficient at breaking down dopamine in the prefrontal cortex (the front section the brain), which can influence important psychological functions.

All of the research groups agree that there is a relationship between the COMT gene and hypnotisability from their experiments. However, an interesting disagreement arose: which allele made someone more or less hypnotisable. Each research group used a different setting for their experiments, with some using group hypnosis and some using individual sessions. Szekely et al., (2017) went on to theorise that setting may influence the level of arousal in the prefrontal cortex. High-arousal situations, such as group hypnosis, were theorised to be more effective for those with more of the efficient valine allele, whereas low-intensity settings may be more beneficial for those with a mixture of valine and methionine alleles. All of the research groups were at least able to agree that people who produced only methionine alleles were correlated with being the least hypnotisable.

As well as looking at our genetic makeup, researchers have also examined the brain itself in the search for answers. Advancements in modern technology in the 21^st century have allowed us to get a good look at what goes on inside our heads during different processes, and hypnosis has not escaped the curiosity of neuroscientists. Alkins & Ray (2000) were some such researchers. Alkins & Ray took a close look at the frontal lobe, otherwise known as the pre-frontal cortex, drawing on previous research from neuropsychological research on people with frontal lobe dysfunction. A small group of participants were given different tests to assess their executive functioning and the researchers compared their results with their levels of hypnotisability. Alkins & Ray found that the people who performed significantly better in tests involving increased cognitive flexibility also were highly susceptible to hypnosis. Whilst this correlation helps to shed some more light on the role of the brain in hypnosis, the study left questions unanswered by way of highlighting any possible causation.

At present, we have certainly uncovered some links between our genetics and our hypnotisability. However, the findings do not answer all of our questions or paint the whole picture. We also need to take a closer look at what other things could influence hypnotisability, and how we can use them to understand hypnosis and how it works at a deeper level.

Oxytocin is a neuropeptide that is implicated in social bonding; it enhances a range of pro-social behaviours in humans and animals. In 2012, Bryant et al. investigated the efficacy of oxytocin as a moderator of hypnotisability. They proposed that increasing the levels of oxytocin in one’s body, in this case via a nasal spray, may enhance the levels of hypnotisability in a person. In their experiment they recruited 40 low-hypnotisable people and prior to a hypnosis session, they were given an intranasal spray of either oxytocin or a placebo. The results from their experiment showed that there was a significant increase in the levels of hypnotic responsiveness in those who had the oxytocin spray compared to the placebo. This study was the first of its kind, and the experimenters are excited to see where this could lead to in the future.

Attention and hypnosis share an undoubtedly strong link. This has been highlighted in many ways, for example in 2020 by Oldon, Stendel & Veissiere when they found a positive correlation between levels of smartphone addiction and hypnotisability in students in the United States. In 2018, Martin, Sackur & Dienes looked into attention as well. In an experiment comparing people of high, medium, or low hypnotisability, the team of researchers asked if sustained attentional ability was involved in this divide. Using a perspective-switching exercise with the image of a nekker cube, the abilities of each group to control their switching of perspectives of which way the cube was facing were compared. They also told some members of each group that previous research had indicated the highest success for their particular group (which was untrue for some groups). Overall, the high-hypnotisability group exerted more control of their ability to change visual perception at will than the other groups. Interestingly, only the high-hypnotisability group were also influenced by the additional information given that people in their group were more skilled at the nekker cube attention task. In short, what this means is that whilst the higher-hypnotisability group did display superior attentional control as has been argued in other research, the experiment also highlighted how sensitive to suggestion the high-group were in comparison to the medium- and low-group, who were not affected by the extra information.

The research discussed here is by no means exhaustive. The academic journals are also littered with unsuccessful explorations, such as a comparison of intelligence and hypnotisability by Geiger et al., (2014). From what researchers have been able to tell us so far, it looks like we are well on the way to accounting for a sizable portion of what could make up our levels of hypnotisability. There are, however, still many elements that remain unknown to us. For now.

Atkins, D., Ray, W. J. (2000). Frontal lobe contributions to hypnotic susceptibility: A neuropsychological screening of executive functioning. International Journal of Clinical and Experimental Hypnosis, 49(4), 320-329. Link: https://doi.org/10.1080/00207140108410081

Bryant, R. A., Hung, L. (2012). Oxytocin enhances social persuasion during hypnosis. PLoS ONE, 8 (4). Link: https://doi.org/10.1371/journal.pone.0060711

Elkins, G. (2014). Hypnotic relaxation therapy: Principles and applications. Springer Publishing.

Elkins, G. R., Barabas’z, A. F., Council, J. R., Spiegel, D. (2015). Advancing research and practice: The revised APA division 30 definition of hypnosis. American Journal of Clinical Hypnosis, 57(4), 378–385. Link: https://doi.org/10.1080/00029157.2015.1011465

Geiger, E., Peter, B., Prade, T., Piesbergen, C. (2014). Intelligence and Hypnotisability: Is there a connection? International Journal of Clinical and Experimental Hypnosis, 62(3), 310-329. Link: https://doi.org/10.1080/00207144.2014.901083

Lichtenberg, P., Bachner-Melman, R., Ebstein, R. P., Crawford, H. J. (2004). Hypnotic susceptibility: Multidimensional relationships with Cloninger’s Tridimensional Personality Questionnaire, COMT polymorphisms, absorption, and attentional characteristics. International Journal of Clinical and Experimental Hypnosis, 52, 47–72. Link: : https://doi.org/10.1076/iceh.52.1.47.23922

Martin, J., Sackur, J., Dienes, Z. (2018). Attention or instruction: do sustained attentional abilities really differ between high and low hypnotisable persons? Psychological Research, 82, 700-707. Link: https://doi.org/10.1007/s00426-017-0850-1

Olson, J. A., Stendel, M., Veissiere, S. (2020). Hypnotised by your phone? Smartphone addiction correlates with hypnotisability. Frontiers in Psychiatry, 11, 578. Link: https://doi.org/10.3389/fpsyt.2020.00578

Patterson, D. R., & Pacek, J. T. (1997). Baseline pain as a moderator of hypnotic analgesia for burn injury treatment. Journal of Consulting and Clinical Psychology, 65(1), 60–67. Link: https://doi.org/10. 1037/0022-006X.65.1.60

Piccione, C., Hilgard, E. R., & Zimbardo, P. (1989). On the degree of stability of measured hypnotizability over a 25-year period. Journal of Personality and Social Psychology, 56(2), 289–295. Link: https://doi.org/10.1037/0022-3514.56.2.289

Raz, A., Fan, J., Posner, M. I. (2005). Neuroimaging and genetic associations of attentional and hypnotic processes. Journal of Physiology, 99, 483-491. Link: https://doi.org/10.1016/j.jphysparis.2006.03.003