Interactions Between Placebo Effects and Mindful Awareness State
Trial statusNot yet recruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-55
SponsorTrustees of Dartmouth College
About this trial
In this experiment,the investigators study the effects of interpersonally induced placebo effects and a mindful awareness induction on negative affect. Specifically, it will be examining the effects of interpersonally induced placebo effects (sham tDCS vs. control) and a mindful awareness induction (mindful state vs. control), as well as their interaction. Each group will undergo fMRI scanning and physiological recording will performing the Multimodal Negative Affect Task (MNAT).
Eligibility criteria
This trial accepts healthy volunteersQualifiers
No self-reported current or history of depression, bipolar disorder, or other psychiatric diagnosis
No self-reported current seizure disorder (i.e., seizure within past 10 years), or history of stroke or other major neurological diagnosis that can cause cognitive impairment
No self-reported current chronic pain, or acute pain within three months of the study period
No current migraine disorder (i.e., 15 headache days or more in 1 month)
Disqualifiers
None
Trial design
Design model
Crossover
Treatments tested in this trial
tDCS stimulation (sham)
BehavioralParticipants will receive sham tDCS stimulation in a 20 minute long task. Targets will be fitted with the tDCS stimulation electrode cap and instructed that they will receive 20 minutes of tDCS stimulation for the task. Sham tDCS will target the motor cortex at 2mA for 15 sec at the beginning of the session, and then the stimulator will turn off. The participant will then sit for the remaining time of the session with the electrode cap on their heads but turned off and not delivering stimulation. All participants will receive sham tDCS stimulation (n=120).
tDCS stimulation (real)
BehavioralIn their second session, participants will receive real tDCS stimulation in a 20 minute long task. Targets will be fitted with the tDCS stimulation electrode cap and instructed that they will receive 20 minutes of tDCS stimulation for the task. Real tDCS stimulation will target the motor cortex at 2mA for 20 minutes (full duration of task). All participants will receive real tDCS stimulation (n=120).
Mindful state induction
BehavioralExperimenters trained in high-competence and high-warmth will train Group 1 participants on mindful state induction (n=60). Participants will undergo two stages for this training: 1) pain education to increase beliefs in endogenous brain regulatory capacities; and 2) the Stanford Hypnotic Induction Profile (HIP) test of hypnotizability and hypnotic induction of a relaxed state receptive to suggestion. In Stage 1, participants will receive education that pain and affect are processes designed to protect the body from danger, which are transmitted rapidly and automatically to the brain. In Stage 2, participants are (a) seated in an upright, alert posture; and (b) receive suggestions that the ability to attend to and discriminate affective perceptions is achievable and that suppressing attention to the body and focusing on the task will allow them to perform optimally under pressure. Mindful state induction will only be explicitly instructed during session 1 for Group 1 participants.
No minfulness induction
BehavioralParticipants in the No-mindfulness group will go through comparable stages but with different instructions. In the first stage, they will receive education about pain and affect as protective processes of the body. In the second stage, they will be seated in an upright, alert posture and receive suggestions to focus on the task and suppress attention to the body.
Treatment groups
120 Participants
are divided into 4 treatment groupsGroup A: mindfulness (session 1)+ real tdcs, sham tdcs (session 2)Experimental treatment 3 interventions
Group B: mindfulness (session 1) + sham tcds, real tdcs (session 2)Experimental treatment 3 interventions
Group C: no mindfulness (session 1) + real tdcs, sham tcds (session 2)Experimental treatment 3 interventions
Group D: no mindfulness (session 1) + sham tdcs, real tdcs (session 2)Experimental treatment 3 interventions
Trial outcomes
Primary outcomes
1
Pain Ratings
Participants report subjective pain experience after each trial on a well-validated Generalized Linear Magnitude scale (GLMS) with anchors of "No pain" and "Most intense pain imaginable". Raw units are on a 0-180 scale.
Time frame
3-10 sec post-stimulus throughout testing sessions, with all sessions complete within 1 month2
Subjective fear ratings
Participants report subjective fear experience after each trial on a well-validated Generalized Linear Magnitude scale (GLMS) with anchors of "No fear" and "Most intense fear imaginable"
Time frame
3-10 sec post-stimulus throughout testing sessions, with all sessions complete within 1 month3
Cognitive effort ratings
Participants report cognitive effort experience after each trial on a well-validated Generalized Linear Magnitude scale (GLMS) with anchors of "No effort" and "Most effort imaginable"
Time frame
3-10 sec post-stimulus throughout testing sessions, with all sessions complete within 1 monthSecondary outcomes
1
Electrodermal autonomic responses to painful heat, fear-related images and cognitive effort.
Skin conductance (EDA) is recorded continuously throughout test sessions and per-stimulus amplitude of canonical stimulus-locked EDA responses is reported in microsiemens (uS). Higher values indicate a higher EDA response.
Time frame
Peri-stimulus throughout testing sessions, with all sessions complete within 1 monthSponsors and contacts
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Source ClinicalTrials.gov
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