You feel me? A randomized trial of tDCS on pain empathy.

Pain empathy has a number of social benefits, but can be problematic in those who feel the pain of others too much. The current study examined the use of transcranial direct current stimulation (tDCS) as a modifier of pain empathy with the expectation that cathodal stimulation would decrease pain empathy. Anxiety and general empathy were controlled for, given past work demonstrating their impact on pain empathy. Participants were randomized to either active (cathodal; n = 55) or sham tDCS (n = 55) at 2 mA for 20 min while watching videos of painful events and completing a pain empathy simulation questionnaire. Bayesian linear regression analysis indicated no evidence that tDCS condition affected pain empathy. However, there was strong evidence in favor of a positive relationship between anxiety and pain empathy, and extreme evidence between general empathy and pain empathy. The current study examined a montage over the temporoparietal junction though future work should also investigate other areas related to pain empathy such as the anterior cingulate cortex. Results provide evidence of the need for stronger methodological considerations with regard to tDCS including larger sample sizes. Further, the connection between anxiety and pain empathy demonstrates the need for treatments to not only target classic anxiety symptoms, but other factors than may worsen daily functioning.