A placebo response refers to the improvement in a patient's clinical symptoms when administered with an inert substance, whereas a nocebo response is the worsening of clinical symptoms. The neuropeptide oxytocin is implicated in social trust, stress/anxiety, and learning processes that also contribute to placebo and nocebo responses. This leads to an intriguing hypothesis that pharmacological manipulation of oxytocin 1nay modulate placebo/nocebo. It has been proposed that oxytocin may enhance social trust, a key element of the patient-doctor relationship, which may further boost placebo effects. Oxytocin has also been shown to be involved in reducing stress and anxiety, which might contribute significantly to the magnitude of nocebo.
LIU, C., HUANG, Y., CHEN, L., & YU, R. (2020). Letter to the editor : Lack of evidence for the effect of oxytocin on placebo analgesia and nocebo hyperalgesia. Psychotherapy and Psychosomatics, 89(3), 185-187. https://doi.org/10.1159/000504967