Understanding The Phenomenon We Call Pain

Pain is a subjective phenomenon we don’t fully understand

Stepping on a Lego brick, stubbing your toe on the edge of a door frame, or catching your finger in a drawer. No, they are not the beginnings of comedy sketches. All those scenarios end in not only a lot of swearing, but a painful sensation that emanates from the area of injury. The reaction occurs in an instant, before slowly subsiding. If we look past the uncomfortable feeling, do you know why pain is essential to our survival?

Cast your mind back to those carefree years as a child. You probably tried rollerblading or skateboarding. Both hurt a lot when you inevitably fell over, crashing to the ground with a hard thud. During our adolescent years, we are far more fearless. We haven't learned to be scared of pain and injuries that can result from sports like skateboarding. Later in life, sometimes even the smallest bump is incredibly painful.

It's not that the phenomenon of pain gets worse as we get older. Instead, pain creates a lasting memory to remind us to avoid injuring ourselves again. More than that, the pain also stops us from touching a broken bone or poking a cut. This is so the body can heal and repair properly. Pain reminds us to withdraw from harmful situations, and has helped the human race to survive for millions of years. As upsetting as being in pain is, without it, things can go very wrong.

Pathway for feeling pain

Before we explore some of the conditions linked to pain, let's start with how we feel pain. Painful sensations do not have a direct link to our brain. Instead, pain relies on several different neurons and nerve pathways to get from the source of pain to our brain and back again. A neuron is a nerve cell that is responsible for transmitting a signal.

If we use the dreaded Lego scenario as an example, stepping on a brick results in nerve endings in the bottom of your foot sensing the injury. These nerves are called nociceptors. That signal is transmitted along nerve fibres and collected in the dorsal horn. The original message is then transferred to another set of neurons designed to travel up to the brain through the spinal cord, before arriving at the thalamus (brain). The thalamus is part of the midbrain and is responsible for organising those signals into a logical order.

Once organised, the signal arrives at the sensory cortex (our emotional response to pain) where it is deciphered and interpreted by the motor cortex (our physical reaction to pain).

The signal then travels back along the same pathways to motor neurons in your foot. You proceed to jump around clutching your foot and cursing. Although there are nearly a dozen stages in “feeling pain”, it all happens in less than a second.

You can probably see why various abnormalities in the way we feel pain exist. It only takes one of those links to become damaged for the normal process to be obstructed.

The pathway is long, and many links can go wrong

An absence of pain - congenital insensitivity to pain (CIP)

Although the concept of feeling no pain at all may sound appealing, especially in the case of the Lego brick, CIP is extremely dangerous. Without any sensation of pain, frequent injuries can occur. If you didn’t know you had broken a bone or contracted a severe infection, you would carry on as usual. The natural survival instinct to let your body heal is lacking.

Those with CIP can still feel if you touch their arm, and in most cases, mild changes in temperature. The condition is the result of the nociceptor in their pain pathway functioning incorrectly. If you posted an important letter, but it never arrived, the recipient wouldn’t know what is going on. Mutations in cells prevent the transmission of pain signals from the site of injury to the brain.

Pain that doesn't hurt - pain asymbolia

In pain asymbolia, it is not the nociceptor that is damaged, but the sensory cortex. Its ability to decipher the signal of pain and prompt a painful emotional trigger is missing. A physical reaction to pain is only one aspect. Take a minute to think about the actual emotional sensation of pain.

What if you cut your arm and could feel the skin being damaged, but the feeling was pleasant, rather than unpleasant? The challenge for those living with pain asymbolia is not that they can’t feel pain, but that their brain doesn't recognise it as a negative sensation. Although we cannot change the intensity of pain, we can still attempt to improve our emotional response to it. This is especially important for those living with pain asymbolia; they need to learn that pain and actions that cause pain should be avoided.

Examples of mind over matter are present throughout history. The Hindu ceremony of walking on fire and Buddhist monks who are struck repeatedly are prime examples. Both disciplines share a conventional method for dealing with pain—meditation. By channelling our minds, we can attempt to lessen the impact of pain and our emotional response. In some cases, mindfulness meditation can reduce pain unpleasantness by up to 57%.

Non-existent real pain - phantom limb pain (PLP)

Phantom limb pain is when a sensation of pain exists even when a limb has been removed. Despite PLP being present in 50–80% of amputees, researchers still are not entirely sure how this phenomenon occurs. How do you treat a painful sensation that technically doesn't exist? One such method is mirror therapy.

By visualising the missing limb in front of a mirror and trying to hold it as though it were present, the idea is to acknowledge the sensation of pain, rather than ignore it. It’s almost like reassuring your body that you know the limb is missing so it can stop telling you via the sensation of pain. Even when it doesn't make logical sense, the pain is still real and needs treatment.

Living with pain - chronic pain

Chronic pain is the broad term for when a prolonged period of pain is experienced. It can be the result of any part of the pain pathway becoming damaged, or not working correctly. As many as one in five European adults suffer from chronic pain, with two significant categories of pain existing.

Both nociceptive and neuropathic pain can be incredibly debilitating. They affect a patient’s mental health and their ability to carry out everyday tasks. Many of those living with chronic pain are unresponsive to traditional pain medication and struggle to work full-time. In these cases, self-treatment, like mindfulness meditation and lifestyle changes, play a major role in chronic pain management. Treatment of pain is not a simple “one-size-fits-all” approach. The concept is far more sophisticated.