Even emotion has genetic basis. This is demonstrated by research conducted at the University of California in Los Angeles, the results of which were published in the journal Proceedings of the National Academy of Sciences. According to scientists, it would be the Oprm-1 gene that regulates the intensity of the response to social rejection, causing each of us to react differently to exclusion from a group of friends, disappointment in love and family misunderstandings. Emotional suffering is often described in terms typical of physical pain: words hurt, hearts break, and relationships burn. Indeed, the findings of the new research show that the brain circuits responsible for perceiving these two types of sensation are the same. In fact, the Oprm-1 gene regulates the activity of opioid receptors, known for their ability to reduce pain and perceive pleasant sensations. The researchers analyzed the sequence of Oprm-1 in 122 individuals and, at the same time, asked the same subjects to answer questionnaires that allowed them to determine their level of sensitivity to social rejection. Thus, it was discovered that in the most sensitive subjects there is a rare variant of this gene, in the past already associated with a more acute perception of physical pain. Furthermore, by monitoring brain activity it has been shown that only people with this form of Oprm-1 experience strong discomfort when they are involved in a virtual game in which they are progressively excluded from the game itself. Finally, the sensitive variant of the gene has been observed to be much more common in individuals of Asian descent than in Caucasians. This could justify some social conventions typical of Asian populations: if social exclusion is painful, following behavioral rules would be a way to prevent despondency. According to Naomi Eisemberg, one of the authors of the study, psychological suffering could be a means to avoid the loss of social relationships. In fact, during evolution, perceiving social rejection as physical pain would have made it possible to ensure survival, for example by guaranteeing protection from predators. "It helps us make sure we stay in touch," Eisenberg said. Not surprisingly, therefore, the hypothesis that the two functions may have evolved simultaneously to use the same brain circuitry. Source: Way BM, Taylor SE, Eisenberger NI. Variation in the micro-opioid receptor gene (OPRM1) is associated with dispositional and neural sensitivity to social rejection. Proc Natl Acad Sci US A. 2009 Sep 1;106(35):15079-84. Epub 2009 Aug 14.