Pain has arisen as part of human evolution because the sensation increases our survival rate. It protects us from danger by generating negative feelings so that we try to avoid the cause of the pain in future. This theory applies to both physical and emotional pain. Since evolving from apes, humans live together in societies so responsibilities can be shared between individuals and complex activities like hunting and gathering are more successful. Therefore, bonds between individuals can be considered vital for survival, which is the reason why emotional pain from social rejections or break ups feels as real as physical pain.
Since the early 1970s, experiments have been conducted to investigate which region of the brain is responsible for pain, but pain is not well defined. In our own minds, we can clearly distinguish between emotional sources of pain and those triggered by injuries, yet we describe them both as a “painful experience”. To analyse the problem, scientists divided pain into two components: the affective, which is responsible for the uncomfortable and stressful feeling; and the sensory, where the intensity and location of the pain can be identified. The sensory component is dominated by physical pain, while the affective component often expresses in both emotional and physical pain. Brain scans show that the dorsal anterior cingulated cortex (dACC) and the anterior insula cortex are the main regions activated when the affective component is felt, but dACC activity has also been detected in the sensory component when physical pain is felt. It seems the two types of pains, at least in part, share a neurobiological pathway.
So last year researchers led by Naomi Eisenberger at University of California, Los Angeles investigated the cross-over. The team found that people who are more sensitive to physical pain are also more sensitive to emotional pain. This is considered to be one of the consequences of an overlapping pathway. Her group also studied the cross relation of corresponding drugs, i.e. whether physical pain drugs can sooth emotional pain and vice versa. Interestingly, Tylenol, a common (physical) pain killer, works by reducing activity in both the dACC and anterior insula. Individuals who felt emotional stress also showed signs of being significantly soothed after taking the drug.
Despite research being at a very early stage, these results offer the possibility of a promising future where emotional pain can be dealt with medically, instead of relying wholly on the healing power of time.
Whether we’d want to take such pills is another argument entirely; after all, many would say that when it comes to emotions, it’s the pain that makes us stronger.
IMAGE: Skley, flickr