A fear that makes you vomit, a refusal that burns, a mourning that paralyzes: emotional suffering can manifest itself with physical symptoms. For centuries, writers and musicians have described this close bond in words and notes, which is more difficult for scientists to explain. Recently, however, new discoveries have made it possible to identify the mechanisms common to the two types of pain, clarifying their link and paving the way for more effective treatments for some of the most debilitating pathologies.
While senses such as sight and hearing have nerve pathways that lead from the eyes and ears to a specific brain region, the brain’s response to pain is more complex because it also involves thoughts and emotions. This is why a good book can, for example, ease a toothache and a sunburn hurt more if we are down in the dumps.
Emotions, however, are not limited to affecting an already present physical pain. Anxiety caused by bereavement or embarrassment can produce pain that, while having no physical cause, is no less real. Brain scans show similar activity in the pain region, which includes the insula, thalamus and anterior cingulate cortex, triggered by stimuli related to both physical and psychological distress, such as social rejection.
Understanding the emotional aspects of pain could help you cope better with some mental disorders. It is estimated that up to 75 percent of people with chronic pain also experience anxiety or depression. “Predisposition for one of these disorders increases the likelihood of developing the other,” says Felix Brandl of the Technical University of Munich in Germany. Brandl and his colleagues carried out a meta-analysis of 320 studies of brain scans of people suffering from chronic pain, anxiety and depression, finding that they shared some changes in the brain, including a reduction in its volume and changes in neural connections. both in the prefrontal cortex, involved in the formation of opinions and targeted actions, and in the insula, involved in emotions, perceptions and self-awareness. Brandl says psychotherapy and antidepressants work in all three cases. “Having identified this overlap, we can develop combined therapeutic strategies,” he explains.
Another potential explanation for the coexistence of chronic pain and emotional disturbances is that they are both the result of chemical imbalances in the ventral pallidum, a brain region involved in the urge to avoid pain and seek pleasure. Here two chemicals are released, glutamate and Gaba, which induce behaviors associated respectively with fear and pain, and with reward. Bo Li of the Cold spring harbor laboratory in New York, in the United States, hypothesizes that disorders such as chronic pain or depression are linked to the alteration of the normal balance between the two substances, which produces an increase in sensitivity to potential threats, making the people more prone to pain and the instinct to withdraw into themselves, suffocating the joy of reward. “This is a typical symptom of depression,” Li says.
Bearing in mind that emotional and physical pain are related and have the same neurological signature, in 2015 Choong-Wan Woo and his colleagues at the University of Colorado in Boulder, USA, distinguished for the first time specific neural pathways associated with physical suffering from the psychological one, an important step forward to deal with cases of chronic pain or fibromyalgia, which tend to be influenced by the state of mind.
The relationship between physical and emotional pain is complex, but the overlapping mechanisms of the brain have a clear benefit for both: Perhaps you already have a remedy for some emotional pain in your medicine cabinet. In 2011, in fact, some researchers discovered that paracetamol, in addition to physical pain, reduces that associated with social rejection. And, confirming the importance of the mind, it is more effective when combined with the forgiveness of whoever caused it. ◆ sdf