The Effect of Hypnosis on Blood Concentrations of Endocannabinoids

Hypnosis is a therapeutic method in which the experimenter or therapist make suggestions to individuals after they have undergone a hypnotic induction. This induction is a relaxation procedure designed to focus one's mind and to induce a hypnotic trance in individuals. The hypnotic trance consists in a state of deep absorption, concentration and altered sensations, cognitions and behaviors. Hypnosis can be used for pain control in experimental and clinical settings. In this study, standardized hypnosis including a relaxation technique for the hypnotic induction and a direct hypnotic analgesia technique for the hypnotic suggestions will be used.

Meditation is a relaxation method that can be used to reduce pain symptoms and pain perception in clinical and experimental situations. In this study, a standardized mindfulness meditation session of 20 minutes will be used to induce a relaxation and an analgesic effect in participants. Mindfulness meditation is a practice intended to increase mindfulness and awareness of the self and the environment by techniques of controlled breathing, focus on neutral elements, and observation of one's thoughts and emotions without judgment.

Conditioned pain modulation (CPM) is a pain inhibition mechanism that is used to assess endogenous analgesia capacity. The method to evaluate CPM in healthy individuals and patients with pain includes both a conditioning stimulus (a noxious stimulus that induces CPM) and a test stimulus (a noxious stimulus used to evaluate the analgesic response to the conditioning stimulus). In this study, the conditioning stimulus will be a cold pressor test (two-minutes immersion of one hand in ice water) and the test stimulus will be a two-minutes thermal noxious stimulus delivered by a contact thermode.

A placebo is a substance (or treatment) with no active therapeutic effect. The placebo effect (analgesia) in this study will be induced by the oral administration of one inert tablet (sugar pill). The tablet is a round, hard, white, flat-faced tablet with no active ingredient. The participant is told that the tablet is an active drug, more specifically an analgesic or a painkiller, that is used to achieve analgesia, relief from pain. This placebo condition is used to induce a diffuse analgesic effect in participants.