An observational study in Chronic Widespread Pain, sponsored by Vrije Universiteit Brussel. Completed at 1 site in Belgium. Open to female participants aged 18 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-09-19.
Sponsored by Vrije Universiteit Brussel · Observational
Patients with chronic widespread pain (CWP) frequently experience stress intolerance - an exacerbation of symptoms in response to stress. Although it severely affects their quality of life, stress intolerance remains a mystery. Hence, unravelling the mechanisms underlying stress intolerance is crucial to understand CWP pathophysiology and to develop novel treatments. Epigenetic mechanisms hold the potential to provide an answer as they have been found to be altered in patients with CWP at baseline, and in response to stress. However, research on epigenetic mechanisms in CWP is very scarce. Hence, this study aims to address this knowledge gap by assessing stress-induced epigenetic changes in patients with CWP and healthy controls aiming to unravel whether epigenetic mechanisms can help explain stress intolerance. The regulatory role of epigenetic mechanisms will be researched in relation to the activity of enzymes affected by the epigenetic mechanisms, neurophysiological measures, and stress-induced symptom changes in patients with CWP.
The objectives of this project will be tackled by a randomized cross-over study including 44 patients with CWP and 44 healthy controls. Participants are expected to come to the hospital twice and fill in questionnaires at several defined timepoints. Two days before their first visit, participants will complete baseline questionnaires at home via REDCap, which will take approximately one hour. Next, participants will be randomised into Group 1 (undergoing the mental stress test at their first visit and then relaxation breathing) or Group 2 (undergoing relaxation breathing at their first visit and then the mental stress test). During each hospital visit, the participants will be assessed before, during and after the intervention. The Pre-test assessment consists of a blood withdrawal, five short questionnaires, examination of pain thresholds, and neurophysiological measurements. The latter will continue during the intervention, which consists of a mental stress test or relaxation breathing. The Post-test assessment consists of a blood withdrawal, one short questionnaire, examination of pain thresholds, and neurophysiological measurements. Then there are again 2 home-based assessments via REDCap 24h and 7 days after the intervention during which the participants will in 1 or 5 short questionnaires, respectively.
2,930 studies on the registry are indexed under Chronic Pain; 701 are open to participants now.
This study's enrollment of 84 is below the median of 126 across 688 observational studies indexed under Chronic Pain.
Browse Chronic Pain studies →Vrije Universiteit Brussel is the lead sponsor of 154 studies on the registry; 43 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Potential study participants will be recruited mainly through online advertisements, but also in hospitals.
Exclusion Criteria:
Women who received the diagnosis of fibromyalgia from a doctor.
Other: Montreal Imaging Stress Test · Other: Relaxation breathing
Healthy women without any chronic diseases or pain in daily life.
Other: Montreal Imaging Stress Test · Other: Relaxation breathing
A mental stress test that induces stress via a series of arithmetic tasks participants need to solve in a few seconds.
3 short sessions (4 minutes) of relaxation breathing
DNA methylation of catecholamine-degrading enzymes
DNA methylation status of catechol-O-methyltransferase (COMT), monoamine oxidase (MAO)-A and MAO-B
Time frame: At baseline (i.e. before the mental stress test or relaxation breathing), and 20 minutes after the mental stress test and relaxation breathing
Genetic variations in catecholamine-degrading enzymes
COMT: rs4818; rs4680 MAO-A: rs6323; MAOA-uVNTR MAO-B: rs1799836 COMT: rs4818; rs4680 MAO-A: rs6323; MAOA-uVNTR MAO-B: rs1799836 COMT: rs4818; rs4680 MAO-A: rs6323; MAOA-uVNTR MAO-B: rs1799836 COMT: rs4818; rs4680; MAO-A: rs6323; MAOA-uVNTR; MAO-B: rs1799836
Time frame: At baseline
Catecholamine levels
Levels of adrenaline, noradrenaline and dopamine in plasma
Time frame: At baseline (i.e. before the mental stress test or relaxation breathing), and 20 minutes after the mental stress test and relaxation breathing
Heart rate variability
Heart rate variability measured continuously using the Polar H10
Time frame: Continuously starting 10 minutes before until 10 minutes after the mental stress test and relaxation breathing
Blood pressure
Blood pressure, both systolic and diastolic, measured at specified moments using a digital device
Time frame: At baseline (i.e. before the mental stress test or relaxation breathing), during (3 times with 4 minutes in between) and 10 minutes after the mental stress test and relaxation breathing
Activity of catecholamine-degrading enzymes
Activity of the enzymes will be defined in plasma or PBMCs
Time frame: At baseline (i.e. before the mental stress test or relaxation breathing), and 20 minutes after the mental stress test and relaxation breathing
Symptom severity
Symptom severity which is assessed through the Chronic Fatigue Syndrome Symptom List
Time frame: At baseline (i.e. before the mental stress test or relaxation breathing), and 10 minutes, 24 hours and 7 days after the mental stress test and relaxation breathing
Temperature and pressure pain thresholds
Pain thresholds for warmth and cold measured with the TSA-II, and pressure measured with a digital algometer on the hand and leg. Pain intensity is reported through a numeric rating scale ranging from 0 (no pain) to 10 (worst pain).
Time frame: At baseline (i.e. before the mental stress test or relaxation breathing), and 20 minutes after the mental stress test and relaxation breathing
Level of stress
Numeric rating scale ranging from 0 (no stress) to 10 (worst stress) indicating the level of stress
Time frame: At baseline (i.e. before the mental stress test or relaxation breathing), during (3 times with 4 minutes in between) and 10 minutes, 24 hours and 7 days after the mental stress test and relaxation breathing
This study is completed, as verified in Sep 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Vrije Universiteit Brussel