Examination of Psychological and Physiological Pathways Linking Gratitude and Pain and the Moderating Effects of COMT Genotype on These Associations
Phase: NA
Conditions: Acute Pain, Positive Thinking, Emotions
Sponsor: Black Hills State University

Study Protocol 
 
Examination of Psychological and Physiological Pathways Linking Gratitude and Pain 
 
Dr. Nathan T. Deichert 
 
NCT Number: NCT06317844 
 
Approved by BHSU IRB on 04/24/24 
 
 

Study Protocol 
 
Experimental Design:  This one-year randomized controlled trial will begin in September 2024 and 
conclude by August 2025.  Participants will be recruited through flyers and word of mouth.  Flyers 
will be posted electronically on the BHSU campus and through weekly email updates.  Interested 
participants will contact Dr. Deichert’s research lab to enroll in the study.  Given that the study will 
be collecting data from human subjects, the study protocol will be reviewed and approved by the 
Black Hills State University institutional review board as well as the National Institutes of Health 
prior to participant recruitment.  The study will seek to enroll a convenience sample of 150 pain-
free healthy individuals who are 18 years of age or older.  Exclusionary criteria includes: 1) 
cardiovascular disease, 2) Raynaud’s disease, 3) epilepsy, 4) being pregnant, 5) having a current 
injury to or open cut or sore on one’s non-dominant hand, 6) history of fainting or seizures, 7) history 
of frostbite, 8) diagnosed with a chronic pain conditions, 9) diabetes, 10) malignant tumor, 11) 
chronic lung disease, 12) liver disease, 13) kidney disease, 14) gastrointestinal diseases, and 15) 
individuals currently taking opioids.  There will be no restrictions based on race or gender. 
 
This intervention will consist of a single visit to the PI’s research laboratory (see Figure 1).  During 
this visit, participants will be screened for eligibility and informed of the study procedures.  After 
giving consent, participants will complete a series of questionnaires.  First, participants will 
complete a brief demographic questionnaire measuring age, sex, body mass index (BMI), current 
smoking status, subjective socioeconomic status (SES), and experience with gratitude journaling.  
Participants will then complete a series of questionnaires assessing psychological functioning 
including depression (Patient Health Questionnaire-9), anxiety (Generalized Anxiety Disorder-7), 
and perceived stress (Perceived Stress Scale-10) followed by measures assessing baseline levels of 
pain severity (PROMIS Scale 2.0 – Pain Intensity 3a), pain interference (PROMIS Short Form v1.1 – 
Pain Interference 8a) and pain cognitions (Coping Strategies Questionnaire).  Trait and state levels 
of gratitude will be assessed using both the Gratitude Questionnaire 6-item form and the Gratitude 
Adjective Checklist.  Following completion of the baseline questionnaires, participants will be 
randomly assigned to one of two intervention writing conditions. In the gratitude writing condition, 
participants will write continuously for 5 minutes about someone they are grateful for. Participants 
in the neutral writing condition will write continuously for 5 minutes about how they got to the 
research laboratory.  After the writing task is completed, participants will report on their state levels 
of gratitude and be given instructions regarding the cold pressor test and be asked to submerge 
their non-dominant hand into the cold pressor apparatus for up to 1.5 minutes, reporting their 
current level of pain every 15 seconds (participants may withdraw their hand at any point during the 
CPT).  Cognitive reactions to pain will be assessed immediately following the cold pressor test using 
the Rumination and Reappraisal subscales of the Pain-Related Cognitive Processes Questionnaire.   
 
To test the effectiveness of gratitude writing interventions to buffer individuals’ physiological 
responses to stress, saliva samples will be sampled at 4 time points: 1) immediately following 
completion of baseline demographic and psychological measures, 2) immediately following the 
experimental writing task, 3) 2-minutes post-CPT, and 4) 10-minutes post-CPT.  Samples will be 
collected using the passive drool method and will be labelled and stored in a -20˚C freezer. 
 
To test the hypothesis that COMT genotype will moderate the effects of a brief gratitude writing 
intervention to influence pain-related outcomes, buccal cells will be collected via cheek swab from 
all participants at the completion of the experimental procedure.  Cells will be collected by 

scraping the inside of each cheek for 15 to 20 seconds. Following the conclusion of the 
experimental procedure, cell samples will be stored in a -20˚C freezer until DNA extraction 
and genotype analysis. DNA will be extracted from the buccal cell samples and participants will be 
genotyped on the val158met single nucleotide polymorphism (SNP).