Testing the effectiveness of learning procedures in reversing nocebo hyperalgesia

Three experimental groups and one control were formed to investigate nocebo effects. In the nocebo induction phase, low-intensity electrical stimuli were administered without a placebo, while high-intensity stimuli were given with a placebo. Moderate stimuli were also applied with and without a placebo to assess nocebo hyperalgesia. In the nocebo attenuation phase, participants underwent various interventions: 1) low-intensity stimuli with a placebo and high-intensity stimuli without a placebo (counterconditioning), 2) moderate-intensity stimuli with- and without a placebo, coupled with rewards for low pain ratings following placebo (operant conditioning), 3) moderate-intensity stimuli with- and without a placebo, accompanied by exposure to others’ pain ratings indicating low pain when the placebo was applied (verbal modeling). Next, moderate stimuli were administered with and without a placebo to evaluate the impact of the interventions on attenuating nocebo hyperalgesia.