The purpose of this study is to evaluate and compare the immediate effects of self-hypnosis, mindfulness meditation and a spiritual intervention relative to a control condition for increasing pain tolerance and reducing pain intensity and pain-related stress, in response to experimental painful stimulation.

The primary aim of this study (Aim 1) is to compare the immediate effects of self-hypnosis (SH), mindfulness meditation (MM), and Christian meditation (CM), relative to a control group (CN), for increasing pain tolerance and reducing pain intensity and pain-related stress, in response to experimental painful stimulation in a sample of healthy volunteers.

An exploratory aim of this study (Aim 2) is to identify possible shared and unique predictors of response to the three treatment conditions. The possible predictors we plan to test include sex, age, religious affiliation, hypnotic suggestibility, baseline mindfulness, acceptance, pain-related beliefs, religiosity, trait spirituality, previous experience with SH, MM and CP, outcome expectancies, and trait absorption.

This is a randomized quantitative experimental mixed-model repeated-measures study with three assessment points: baseline (T0), pre-test (T1), and post-test (T2). Eligible healthy adults will be randomized to one of the four study conditions. Interventions will be a 20-minutes audio-guided practice of either self-hypnosis, mindfulness meditation, or Christian prayer. Participants in the control group will not be instructed to use any specific strategy during the painful stimulation. Participants will be submitted to a first cycle of Cold Pressor Arm Wrap. They will then listen to a 20-minutes audio recording inducing one of the three interventions, or, in the case of the control group, to a 20-minutes recording of a natural history textbook. Primary outcomes are pain intensity, pain tolerance, and pain-related stress as measured by salivary cortisol level and heart rate variability.

Inclusion Criteria:

• 18 years old or older;
• able to read, speak and understand Portuguese;
• willing to be randomly assigned to all four conditions (regardless of participant's own religious affiliation)

Exclusion Criteria:

• reporting history of musculoskeletal problems, cancer, heart disease, stroke, epilepsy, diabetes, or Raynaud syndrome;
• having an open wound, cut, or fracture in any of the upper limbs;
• self-reported alcohol or substance dependence;
• cognitive or physical impairment, or severe psychopathology that could prevent participation.

Both participants and the experimenter who will conduct assessments and administer the audio-recorded interventions will be blind to the condition to which subjects will be assigned and to the study hypotheses. During informed consent, prospective participants will be told that they will listen to an audio-recording that previous research found to be helpful to pain management, and that the purpose of the study is to assess this the effects of this audio-recording on discomfort associated with the sensation of coldness. Participants will also be instructed not to disclose details of the content of the audios they receive to the experimenter. The research staff member responsible for participants' randomization will be blind to identifying information and to the code identifying each condition.