Hypnosis is a poorly understood psychological phenomenon.15% of the population is considered to be being highly hypnotisable (Woody et al., 2005). Genetic factors are likely to be playing a role; as shown by a study indicating that Monozygotic twins have greater concordance of hypnotizability than dizygotic twin.It is also shown that COMT Val/ Met heterozygous are more hypnotisable. (not replicated though)
Neodissociation theory of hypnosis : Hypnotic experience is achieved by the capacity to disengage from external reality and becomes fully absorbed in one’s internally constructed experience, which is shaped by the hypnotic suggestion. This is linked to an elevated capacity to disengage attention from external stimuli or the extent to which one is engaged with the external world. Oxytocin plays a central role in engaging with outside environment , it can enhance sensitivity to social cues. Oxytocin receptor gene (OXTR) is linked to social affiliation. Could OXTR polymorphisms explain the difference in hypnotisability?
Richard A. Bryant , Lynette Hung , Carol Dobson-Stone and Peter R. Schofield from Australia report the results of an interesting study.Polymorphisms in the oxytocin receptor gene was studied in 185 Caucasian individuals and this was matched with independently completed standardized measures of hypnotisability and absorption. This was measured by having the participants respond to audio recorded hypnotic suggestions in the absence of an individual hypnotist.
The researchers found that participants with the GG genotype for rs53576 ( a single nucleotide polymorphism in OXTR) were characterised by lower hypnotisability. Though the amount of variance accounted for by this SNP was small , authors claim this to be meaningful and comparable to results of other genetic association studies.
Administration of oxytocin via intranasal infusion has been shown to increased hypnotic response relative to placebo in another study.
Limitations: small sample, group administered hypnosis test rather than individually administered one.
Conclusions: The biological mechanisms behind hypnotisability is still unclear. Oxytocin might play a role in suggestibility.
Summary of the article:
Bryant RA, Hung L, Dobson-Stone C, Schofield PR. Psychoneuroendocrinology. 2013 Oct;38(10):1979-84