Placebo capsules and nasal spray
Both the placebo capsules and the placebo nasal spray were delivered in a printed pharmaceutical package, which included a package insert and a blister filled with seven white cellulose capsules or a labeled nasal spray bottle with pump dispenser, respectively. The package provided information on the name of the placebo along with administering information, such as symptom indication and dosage instructions. In the active nasal spray condition only, information on side effects was provided. In addition, similarly to a typical medication, general information (e.g., “keep out of reach of children”, “without preservatives”, “for use in adults 18 years of age or older”, “produced in Germany”, “store in a cool and dry place and away from light”), expiration date, fake charge number and a series of fake barcodes and numbers were displayed on the package. The passive nasal spray contained only sesame oil, so that neither the passive nasal spray nor the placebo capsules produced any noticeable side effects. The active nasal spray contained sesame oil and a small amount of capsaicin (0.0007%) to induce a prickling sensation in the nose in order to mimic side effects and to simulate the onset of a drug-like effect. Participants were told that potentially appearing sensations were induced by the filling material and were assured that there was no active pharmacological ingredient in the nasal spray. Participants of both nasal spray groups received the same information. The experimenter and the participants were blinded to group allocation (active vs. passive nasal spray).