We know that some people are more sensitive to pain than others, but we don’t always understand why. Several factors influence this difference, especially the genetic aspect. We are going to tell you what science knows until today about sensitivity to pain. The existence of people more sensitive to pain than others is common knowledge. We have all experienced this difference firsthand. Among different individuals, even the same age or the same family, pain sensitivity can be highly variable. In the same way, the response of each organism to analgesics to treat pain is highly variable.
But what is pain? It is not totally easy to define. In the scientific community, there is a consensus in describing that pain is an unpleasant experience associated with real damage or potential damage.
Because it is difficult to define, it is also difficult to treat and interpret. For general practitioners, dealing with a pain situation is a difficult task. If we add to this the fact that some people are more sensitive to pain than others, then finding the right pain approach for each person becomes a thorny path.
It is estimated that more than half of the changes in pain sensitivity among humans can be attributed to genetic causes. Basically, it’s like saying that the pain threshold we endure is in our DNA.
The pain threshold is the minimum amount of stimulus that can be endured until we feel the sensation that we identify as painful. This threshold is specific to each individual and is modified by some other factors, other than genetics, which we are now telling you about.
Pain sensitivity factors
As we anticipated, there are people more sensitive to pain than others for genetic reasons. But that genetics is affected continuously and with the passage of time. The factors that affect it are:
- Epigenetics: Some scientific studies have analyzed the pain sensitivity of identical twins in order to discover variability on genetics. Twins have the same DNA content, but they do not react the same to pain. Studies conclude that social context and lifestyle modify the pain threshold.
- Desensitization: pain is a sensation perceived by receptors in the body called nociceptors. When the pain stimulus is chronic and is prolonged in time, the nociceptors turn off. That is desensitization.
- Attention: It is also known that the attention given to pain can increase or decrease it. In exercises where the patient with pain is proposed to pay attention to other things, the pain tends to be perceived as milder.
- Sleep: there are people more sensitive to pain than others due to a bad rest. Scientific studies have also investigated this variable and found results that indicate that bad sleep increases brain activity in areas that interpret pain. The worse the rest, the lower the pain threshold.
The least sensitive to pain
There are unusual genetic alterations where the result is insensitivity to pain. At the beginning of its discovery, this condition was called pure analgesia. With time and the greater understanding of genetics the diagnosis became more precise. Today we have identity for the alterations, such as the channelopathy of insensitivity to pain or the mutation of the SCN11A gene.
Genetic mutations that alter pain sensitivity leading to analgesia usually consist of changes in nociceptors. Some other mutations affect the nerves that carry pain information to the brain.
Although it seems an advantage over people more sensitive to pain, in reality it is not. The absence of pain is a danger to the life of those who have this characteristic.
By not perceiving pain, the body loses the opportunity to respond to potential or actual dangers. Let’s imagine that driving a nail into the foot did not elicit a defense response and the nail caused an infection. In the same way, if an internal organ pain does not give the corresponding warning, the disease can advance to death, even.
People most sensitive to pain
At the other extreme, as opposed to those who are insensitive to pain, we have the most sensitive to pain. They are the ones who interpret pain signals in an exaggerated way, making even the least bit unbearable. Also, in this disorder there are genetic alterations with first and last names, such as primary erythemalgia. The affected gene is SCN9A, which will increase the nerve transmission of pain.
Anyway, beyond the genetic, there are people more sensitive to pain than others because of morphines and addictions. Individuals who chronically use morphine derivatives as pain relievers, or who are addicted to heroin, may become more sensitive to pain over time.
This state of hyperalgesia is usually associated with another known as allodynia. Allodynia is pain that is generated by situations that should not be painful, such as rubbing clothing, for example. Those who are more sensitive to pain usually feel pain from low stimuli.