The use of placebos to alleviate physical pain is well established, but placebo effects on emotional pain are not as well understood. In a new functional magnetic resonance imaging (fMRI) study, researchers examined the impact of a placebo on social pain stemming from a recent romantic breakup.
Young adults who were told that the saline nasal spray they received was a powerful analgesic for both physical and emotional pain reported reduced negative feelings while viewing a photograph of their ex compared to those who were told that the same spray was used to improve the quality of fMRI images. Those in the placebo group also had reduced activation of a pattern of brain activity associated with social rejection.
The placebo increased activity in the dorsolateral prefrontal cortex (dlPFC) in both the social pain test and in a separate physical pain condition in which heat was applied to participants' forearms (however, the placebo effect was more modest in this pain condition). The researchers further identify a pathway between the dlPFC and the periaqueductal gray in the brainstem involved in the regulation of social pain. Overall, the findings suggest that this brain network may underlie the placebo effect across a range of mental health conditions.