Although the beliefs about where the pain originates have varied throughout the years, the desire to elucidate this phenomenon has led to the proposal of many different philosophies. Throughout the history of medicine, several theories have been proposed to explain why and how individuals feel the pain they feel. The underlying foundations of pain perception (and its processing) represent a field of study that has interested researchers for centuries. Furthermore, increased opioid prescription and use, until opioid addiction in the United States and Canada is a dramatic phenomenon that has been responsible for up to 70.000 drug overdose deaths, in 2017. Although it appears that in other countries (e.g., Western Europe) the data is not so alarming. In fact, there are reports that the cost for chronic pain patients is anywhere between 560 to 635 billion dollars annually. This epidemic is growing at an alarmingly fast rate and is taking a significant toll on the economy as well as patients and providers. Currently, in the United States, estimates are that 100 million individuals suffer from the negative effects of protracted courses of pain and inflammation. As a consequence, chronic pain is no longer simply a symptom but becomes itself a disease. Thus, the chronicity of pain is the effect of changes in pain processing through transcription and transduction processes. Again, pieces of evidence suggest the paramount role of the environment (i.e., epigenetic) and genetics. Several mechanisms involving the activation of peripheral and central sensitization pathways through the sensitization of peripheral nociceptors, and alterations in spinal dorsal horn neurons, and central nervous system (CNS) brain areas, can trigger a pathogenetic cascade that ends with the development of chronic pain. Īlthough inflammation and pain are an essential part of healing (acute pain), in some circumstances, they can lead to negative effects. Pain perception, indeed, is a subjective experience, influenced by complex interactions of biological, psychological, and social factors. Pain is the body’s way of telling us there is an injury, and we need to do something about it to ensure that healing occurs. An important consideration when talking about pain is the fact that one patient’s pain is not the same as another patient’s pain, even if they have experienced similar injuries. An individual’s capacity to feel pain is an essential component of the body’s ability to heal.

Pain and pleasure theory