The study is a randomized controlled trial (RCT) parallel-group, assessor blind with one experimental arm, the conditioning open-label placebo (COLP), and one control group following the regular regimen, treatment as usual (TAU).~Tools for assessment: Morphine Equivalent Dose Conversion (MEDC); Pain Pressure Threshold (PPT); Modified Brief Pain Inventory (BPI); PROMIS Pain-Related Measures (PROMIS); Numerical Opioid Side Effects (NOSE); Treatment satisfaction questionnaire for medication (TSQM) and Treatment expectation questionnaire (TEX-Q); Measurements of anxiety, depression - Generalized Anxiety Disorder 7 (GAD7) and Patient Health Questionnaire-9 (PHQ9). Recording of medication changes and side effects. Reported visual analog scale (VAS) for pain assessed by the nursing team and recorded at the electronic medical record (EMR); finally, the qualitative exit interview.~Neurophysiological and metabolomic phenotyping, using the following measures, Quantitative electroencephalography (qEEG) for quantitative assessment (EEG), functional near-infrared spectroscopy (fNIRS), and metabolomics assessment.~Following enrollment, subjects will be randomized to receive COLP treatment or a standard of care opioid dosage. The study team will perform baseline assessments, and subjects in the COLP group will undergo three consecutive days of prescribed - as needed - pro re nata (PRN) opioid 100% dose + opioid conditioning paired with taste and odorous placebos (pill and smell).~Afterward, subjects will receive a 50% dose + COLP for three days. The nursing team will alternate the active opioid medication with total placebo dosages to decrease the therapeutic opioid dose by 50%.~Voluntary COLP continuation: After the participants have completed the experimental intervention (day 6), all outcomes have been collected (pre and post-measurements). Patients randomized to the COLP group will be asked to continue the COLP intervention during hospitalization if the participant agrees to continue using COLP. We will re-evaluate the following variables: MEDC, PPT, BPI, PROMIS pain, TSQM, and NOSE once COLP is discontinued (e.g., in case of increased pain and opioid utilization or if the patient is being discharged and transferred to another facility).~For subjects allocated in the control group (treatment-as-usual), the customary treatment routine will follow the standard of care for patients suffering from mild to moderate pain, including all pharmacological agents (NSAIDs, narcotics, and combos) used for pain management. The study team will record total narcotic dosages at the beginning and end of the trial.
The use of the conditioning open-label placebo (COLP) paradigm will be studied as a dose extension method to lower opioid dosage in patients with spinal cord injury, polytrauma, and burn injury. The goal is to provide the same level of pain relief with a reduced opioid intake to diminish side effects as well as the risk of addiction associated with opioid treatment.