Masters Thesis

Genetic predisposition for hypnotic susceptibility: an introductory study on the potential of genetic predictors

Hypnotherapy is an empirically supported, clinical intervention used in the treatment of a wide variety of mental, physical, and emotional dysfunctions. Hypnotizability is a stable and heritable personality trait. Individual differences in hypnotic susceptibility have been shown to correspond to hypnotherapeutic success. Increasingly, gene variants have been linked to facets of personality as well as their related psychological and physiological disorders. These variants are used as predictors of responses to medical treatments including drugs, psychotherapy, and placebo effects. These studies support hypotheses relating specific gene variants to differences in hypnotizability. This study investigated two allele variants and their associations to susceptibility: the serotonin transporter gene linked polymorphic region 5HTTLPR and the single nucleotide polymorphism of the catechol-O-methyltransferase at Codon 158. A secondary goal was to assess the validity of the Tellegen Absorption Scale (TAS) by comparing scores to actual hypnosis susceptibility. Hypnotic susceptibility was measured using a standardized group induction method – the Harvard Group Scale for Hypnotic Susceptibility (HGSHS-A). Hypnotizability, TAS scores, COMT genotype, and SERT genotype, was measured in 253 participants. There were no main effects of either gene variant on hypnotic susceptibility and no interactions effects between these genes. TAS scores were not significantly correlated with scores on the HGSHS-A, suggesting that TAS is not a valid measure of the hypnotizability construct. These negative results are consistent with other recently published studies. A review of the literature suggests that commonly used testing methods for hypnotic susceptibility may conflate multiple constructs and decrease the probability of detecting susceptibility correlates.