De-stress your physiological activation by compressing your imagination: a brief session of hypnosis decreases sympathetic stress response in moderately stressed dentists

Luca Queirolo^1*Enrico Facco²Andrea Roccon³elisa pistollato⁴Adolfo Di Fiore³teresa fazia⁵Christian Bacci³Gastone Zanette³

• ¹Department of Neuroscience, University of Padua, Padua, Italy
• ²Ist. Franco Granone-Centro Italiano di Ipnosi Clinico Sperimentale, Turin, Italy
• ³School of dentistry, Department of Neuroscience, University of Padua, Padua, Italy
• ⁴Department of Medicine, University of Padua, padua, Italy
• ⁵Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Lombardy, Italy

Aim: This study aims to explore the effect of hypnosis on dentist's physiological stress management.Methods: 20 dentists (Mean=30, SD= 7.37) from the Dental Clinic of the University of Padua participated in the study. Stress assessment was performed by recording physiological parameters, including heart rate (HR), heart rate variability (HRV), electrodermal activity (EDA), skin conductance responses (SCR) and the administration of the psychological stress perceived stress scale (PSS-10). Following the induction of hypnosis, the participants were led to recall and relive a previously agreed, pleasant experience, and the related psycho-physiological changes were monitored. The hypnosis session was planned during a routinary working day. Physiological parameters were recorded using Empatica E4 wristband and eSense galvanometer. Measurements were taken at baseline, during hypnosis and after dehypnotization.Results: Participants exhibited moderate stress levels before hypnosis (mean PSS-10=17.1 ± 8.1). After hypnosis a significant and large decrease in SCR (T-test= 3.24, DF=19, p=0.002, as shown also by Cohen's d=0.724), and an increase in EDA (Wilcoxon= 50, DF=18, p=0.00355) were recorded, while HRV did not show changes. Friedman ANOVA and Nemenyi post-hoc correction indicated that the condition (basal, hypnosis and post-hypnosis) significantly affected SCR levels (p=0.00008), especially in the pre vs post (p=0.012313) and in the hypnosis vs post comparisons (p=0.00005819). Friedman ANOVA and Durbin-Conover post hoc indicated that conditions (basal, hypnosis or post-hypnosis) also influenced EDA levels, while HRV did not show any significant change (tested with ANOVA Repeated measurement). Pearson's correlation showed that PSS-10 levels were inversely correlated with SCR in hypnosis (p=0.019, DF=18, R=-0.51). A regression model fitting delta SCR (postpre physiological activation) showed that SCR-pre explained part of the outcome (R=0.647, R^2 adj=0.386, AIC=99.6, F=13, RMSE=2.51, p=0.002). Regarding subjective perception 18/20 participants reported feeling better, 2 reported no difference χ² =29.2, p= 0.00000047, df=2. Bayesian T-Test comparing SCR Pre vs Post showed a BF₊₀=20.7, error %=0.000824, which strongly indicates superiority of the effectivness of training in comparison to null hypothesis (>20 times probable an effect than no effect). Conclusion: our data suggests that hypnosis as a valuable resource for stressed dentists. Longitudinal controlled studies and larger samples are necessary to corroborate our results.