Impact of a hypnotic trance on the physiological and subjective stress response to an acute stressor

Clinical hypnosis is a valuable therapeutic tool in the treatment of phobias and acute pain. These conditions have in common that stress constitutes a crucial factor in the genesis and frightening or painful situations. The present study was aimed to investigate whether hypnotic trance has a positive immediate impact on the psychological and physiological responses to an acute stressor.
48 men and women underwent the socially-evaluated cold pressor test and a warm water control procedure in two separated sessions. Beforehand, hypnotic suggestibility was tested with the Harvard Group Scale of Hypnotic Susceptibility. Participants were randomly assigned to three groups: to a hypnotic trance group, an active control group, and a natural history group. Before the stress and the control procedures, the hypnotic trance group received a hypnotic trance strengthening stress resilience and stress coping. The active control group received a non-fictional text together with a suggestion to strengthen resilience. The natural history group received no intervention. After both procedures, participants performed a working memory task. Hormonal, cardiovascular, respiratory, and subjective measures were taken throughout the sessions.
Results show that the hypnotic trance affected hormonel and cardiovascular parameters differently. While cortisol and alpha amylase were generally reduced in the hypnotic trance group, cardiovascular parameters and subjective stress were specifically altered in the stress procedure and modulated by suggestibility.
Our results show the potential of a short hypnotic intervention to positively influence the stress response and the restoration of the homeostasis.