Chronic Pain Clinical Trials

Experimental: Open-Label Placebo

The intervention involves administering P-Dragees blue Lichtenstein, blue placebo pills devoid of active ingredients. Each pill contains lactose monohydrate; magnesium stearate; microcrystalline cellulose; sucrose; glucose syrup; corn-starch; highly dispersed silicon dioxide; white clay; macrogol glycerol hydroxy stearate; Gum arabic; montanglycol wax; povidone; talcum; titanium dioxide; calcium carbonate; macrogol 6000; patent blue V; aluminium salt.~Participants receive an evidence-based rationale, explaining why the placebo treatment is deemed effective for pain. They are informed that the pills are placebos and are instructed to pair them with opioid medication for 7 days. After 7 days until the end of the study they are instructed to continue to pair their opioid medication with an OLP pill and take additionally placebo pills on the basis of their need. During the intervention, participants use electronic monitoring (EM) to track medication and OLP intakes.

Other: Electronic monitoring (EM) control group

EM is a method to objectively measure adherence and serves as the primary intervention component on the basis of which adherence trajectories will be discussed. The participants in the EM control group will receive an evidence-based rational designed to foster positive expectations and will be instructed on the mechanisms of EM.~The EM control group is structurally equivalent to the OLP group referring to the number and duration of contacts between participants and the study team members as well as to the format of the intervention and the quality of the interaction.