On Hypnosis vs. Placebo
Is Hypnosis the Same as Placebo?
In short – not exactly. Hypnosis and placebo indeed share some common components, but there are some critical differences between them. Let's dive right in.
Placebo
Placebo is an umbrella term for physiological responses to an intervention (e.g., substance, treatment) that does not have an intrinsic physiological effect, e.g. a ‘sugar pill.’ The term placebo is Latin for ‘I will please.’ The mere expectation of a positive outcome may to some extent produce one. While deception is a common component of the placebo response, in some cases you can tell people that they are receiving a drug or treatment that has no specific effect but that nonetheless it is expected produce a positive outcome, and that may happen. Because of that, any physiological responses to these interventions are often explained by the intrinsic ability of our brain to create changes in our physiology.
A key component of placebos is the effect of the expectation of reactions (mostly involuntary) to events. For example, expecting to feel less pain after receiving treatment, in the presence of a pain-causing injury, chronic condition, or task may actually produce relief of pain. The strength of the placebo response is also impacted by the symptoms targeted, the perceived dose, the name of intervention, the form of administration, and even the color of the placebo (in the case of a pill) [1]. Furthermore, there are many types of placebo responses. For example, placebo interventions for pain activate different mechanisms in our brain and body: placebo opioids work via the endogenous opioid system, while placebo nonsteroidal anti-inflammatory drugs (NSAIDs) seem to work through our natural endocannabinoid systems.
Hypnosis Vs. Placebo
As we mentioned in our article about what happens in the brain during hypnosis, suggestions given in hypnosis determine what sort of effects are targeted. Hypnosis can be understood through different layers, including hypnotizability (read our article about what it is), absorption (the tendency to become absorbed with experiences), dissociation (the felt disconnection between the self and an experience)[2], and expectancy [1].
While placebo responses are not known to correlate with absorption or dissociation [3], expectancy is a key factor linking hypnosis and placebo responses (although some evidence challenges this statement [4]). Other bridging findings include shared genetic factors (specifically, the COMT polymorphism [5]) and the tendency to be enhanced by oxytocin, the social hormone [4]. However, hypnosis requires no deception whatsoever to be beneficial. Consistently, suggestibility to placebo treatment does not correlate with hypnotizability [6], and neuroimaging studies suggest that hypnosis and placebo are facilitated by largely different regions of the brain [4]. However, for people high in hypnotizability, hypnotic analgesia is far more potent than the effect of a placebo suggestion, while for low hypnotizable people the effect of hypnotic and placebo suggestion is exactly the same.[5]
Placebo treatments are commonly used in clinical research as a control condition for the experimental treatment the study examines. However, using placebo treatments in clinical practice can be very problematic due to the often related deception involved. As deception is only one component affecting the placebo response, placebo treatments can have some effects even when you know you are receiving a placebo (as long as other components, such as expectancy, are still in play) [8]. In fact, while some researchers suggested that hypnosis may be a form of placebo without deception, hypnosis is more powerful for those who are at least moderately hypnotizable [1,6].
Bottom Line
Hypnosis and placebo share common ground in expectancy – expecting them to lead to an effect can increase the extent of their effects. However, evidence from several studies suggests that hypnosis and placebo are separate, building on a key conceptual difference: placebo responses are based on simple expectation, while hypnosis involves learning to focus on and deliberately alter perception and physiological response.
References
Kirsch, I. Response Expectancy and the Placebo Effect. in International Review of Neurobiology vol. 138 81–93 (Elsevier, 2018).
Cardeña, E. & Spiegel, D. Suggestibility, absorption, and dissociation: An integrative model of hypnosis. in Human suggestibility: Advances in theory, research, and application 93–107 (Taylor & Frances/Routledge, 1991).
Lund, K. et al. The magnitude of placebo analgesia effects depends on how they are conceptualized. J. Psychosom. Res. 79, 663–668 (2015).
Parris, B. A. The Prefrontal Cortex and Suggestion: Hypnosis vs. Placebo Effects. Front. Psychol. 7, (2016).
McGlashan TH, Evans FJ, Orne MT. The nature of hypnotic analgesia and placebo response to experimental pain. Psychosomatic medicine. 1969;31(3):227-46.
Raz, A. Hypnobo: Perspectives on Hypnosis and Placebo. Am. J. Clin. Hypn. 50, 29–36 (2007).
Kihlstrom, J. F. The domain of hypnosis, revisited. (Oxford University Press, 2008). doi:10.1093/oxfordhb/9780198570097.013.0002.
Charlesworth, J. E. G. et al. Effects of placebos without deception compared with no treatment: A systematic review and meta-analysis. J. Evid.-Based Med. 10, 97–107 (2017).
About the author:
Afik Faerman, Ph.D. is a postdoctoral scholar at Stanford University. He completed his doctoral training in clinical psychology with an emphasis in neuropsychology, and his clinical training at the University of California, San Francisco (UCSF) and Baylor College of Medicine in Houston, TX. Afik’s research centers on identifying key neurocognitive mechanisms in clinical change, focusing on hypnosis, pain, and sleep. His research was supported and acknowledged by the American Psychological Association, the Society for Clinical and Experimental Hypnosis, and the American Society for Clinical Hypnosis.