Endogenous opioids moderate empathic reactions

The ability to feel the pain of others is based on neurobiological processes which underlie pain experience in oneself. Using innovative methods, an international research team headed by psychologist Claus Lamm from the University of Vienna could show that a reduction of self-experienced pain leads to a reduction in empathy for pain in others as well. The researchers assumed that this effect is underpinned by endogenous opioids and published these results in a recent paper in the peer-reviewed journal "PNAS".



In a study with more than 100 participants, Claus Lamm and his interdisciplinary team used an innovative experimental trick, the so-called placebo analgesia effect, to close an explanatory gap in the understanding of the neurobiological mechanisms of empathy. Experimentally manipulating self-experienced pain, they tested whether this manipulation also leads to an equivalent change in empathy for pain. "Only this trick enabled us to conclude with higher certainty that empathy relies on simulation", explains Claus Lamm from the Department of Basic Psychological Research and Research Methods at the University of Vienna.



Participants in the placebo group reported significantly less subjective pain experience, which was associated with reduced brain activation in anterior insula and midcingulate cortex. "These brain regions are well-known major hubs in the neuronal empathy network. In addition they are central parts of the endogenous opioid system, which is involved in pain regulation", says the psychologist.



In a follow-up study, the research group tested the involvement of the opioid system in the previously observed placebo-empathy effect in order to enable precise conclusions on the underlying neurotransmitter systems. Using a substance that blocks opioid receptors, Lamm and his team induced a blocking of the placebo-empathy effect in 50 participants. "This result strongly suggests an involvement of the opioid system in placebo-empathy, which is an important step to a more mechanistic understanding of empathy", explains the PI Lamm.



What about the direct influence of the opioid system on empathy?

"We are now wondering whether the observed effects in the opioid system act directly on empathic processes or whether these are only carry-over effects of the manipulation of self-experienced pain", explains Claus Lamm. The team is thus currently working on a follow-up study which will investigate direct effects of opioid administration on empathy. "The present results show that empathy is strongly and directly grounded in our own experiences – even in their bodily and neural underpinnings. This might be one reason why feelings of others can affect us so immediately – as we literally feel these feelings as if we were to experience them ourselves, at least partially. On the other hand, these findings also explain why empathy can go wrong – as we judge the feelings of others based on our own perspective", explains Lamm.



This project was funded by the Viennese Science and Technology fund and included cooperation partners at the MR Centre of Excellence at the Medical University of Vienna (Christian Windischberger), at the Department of Clinical Neuroscience at the Karolinksa Institutet in Stockholm, Sweden (Predrag Petrovic), and the Collective Emotions and Social Cognitive Neuroscience Laboratory at the SISSA in Trieste, Italy (Giorgia Silani).



Publication in "Proceedings of the National Academy of Science"

Rütgen, M., Seidel, E.M., Silani, G., Riecansky, I., Hummer, A., Windischberger, C., Petrovic, P., Lamm, C.: Placebo analgesia and its opioidergic regulation suggest that empathy for pain is grounded in self pain. Proceedings of the National Academy of Sciences

DOI: www.pnas.org/cgi/doi/10.1073/pnas.1511269112