What Is Pain?
Having a shared definition of pain will aid in understanding why pain hurts.
Posted January 17, 2019
Today is Saturday, and I’m sitting at my kitchen table, looking outside at the beautiful white snow falling on top of the four inches of snow that fell in my yard last night. I have an ice pack resting across my chronic postmastectomy pain as that allows me to concentrate on other activities I enjoy, including weaving scarves, playing with the dogs, and writing about pain.
My 16-year-old lab mix, Cody, is laying in front of the fireplace to comfort the arthritis that appeared in his hips eight months ago when his best friend, Purl, the pit bull mix, died last spring from canine lymphoma. I’m always sad to see Cody favoring his hips because he’s been such a sweet companion, like when he awoken me in the middle of the night when my then 14-year-old daughter started sneaking out of the house. We all grieve Purl in our own ways, and because I cannot protect Cody from his pain, I hurt inside when I see him hurting. I also have bruises on my legs from happily returning to horseback riding after a 40-year hiatus, I know these bruises should hurt but they don’t. To be perfectly honest, what hurts me most right now is my frustration about being an Alabama girl whose energy-efficient little car can’t go up and down my Iowa driveway to get to the barn where the other riders (Iowans who are used to such snow) are training with a former Olympian in the fine art of dressage.
Every single one of the experiences described above can cause pain – physical, emotional, social, psychological, and spiritual pain. To our remarkable brains, pain is pain is pain. In some special ways, it doesn’t matter to the brain if the pain is caused by a physiological experience or a grieving heart. And due to special neurons (nerve cells) in our brains, if we listen empathetically to the pain experienced by another, our brains will also light up with pain in the same brain areas as the person to whom we are listening.
Pains are always experienced by our brains before we feel them as pains in our bodies. Certainly, that does not mean that the pain is all in our heads!!! There can be no pain sensations without a brain because the brain must first interpret the warning signal sent from the body. The injury itself does not cause pain—the pain that we experienced is the brain’s response to the signal being sent from the injured part of the body. Some of the brain’s responses could include swelling, bruising, bracing, and sometimes pain. The signal must come up the peripheral nerve at the site of injury, to the spinal cord. The spinal cord sends the signal to the brain. The brain oversees interpreting the signal from the periphery. Then, a signal is sent back down the spinal cord and finally from the spinal cord to the periphery. Then the bodily injury can experience pain. Obviously, pain is very complex. As scientists, we are just beginning to understand the phenomenon of pain. I look forward to discussing the newest and most intriguing discoveries of pain science through this blog and the conversations that are generated by you the readers.
First, though, we must start at the beginning…what is pain? The International Association for the Study of Pain, provides the most frequently used definition of pain: “Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.” This definition is important because it notes:
1) pain is unpleasant [in other words, pain hurts];
3) and physically [such as aches, tenderness, shooting, stabbing, numbness]; and
4) pain can be derived from actual tissue damage, the potential for tissue damage, and/or when the experience is represented in terms of damage.
One of the things that is so frustrating about having pain is that pain cannot be seen on any medical test or imaging study. In fact, clinicians cannot tell how much someone is hurting based upon the x-ray, CT scan, or MRI. A person can have absolutely no abnormalities on an MRI and still experience severe pain while another person can have several bulging discs and experience no pains whatsoever.
Importantly, pain serves a vital role in survival. For example, if you are watching someone cooking macaroni on the stove, you will likely see the red flames of the burner heating a pot. You know this flame and pot are dangerously hot. However, as a child, you may have accidentally or on purpose touched the pot coming away with a small and painful blister on your hand. Your mother may have slathered the blister with butter or run cold water over your hand to comfort you. While the blister may have been an annoyance for a few days, it was also your brain’s way of saying: “I’m warning you…Don’t touch that again!!!!!! It’s hot!!!!” So, in a matter of mere fractions of seconds, you learned the natural consequences of touching very hot things. And you can thank your brain for this painful outcome because it may have saved you from many worse future outcomes. Over time, the physical damage from the blister healed. Plus, it is also highly unlikely that you will ever stick your finger on a pot like that again. This kind of pain is often called acute pain. Acute pain occurs at the time of injury and is expected to heal within 3 months. Chronic pain is very different from acute pain; and we will discuss chronic pains in other posts.
My future posts will provide more information about how the amazing brain responds to all kinds of signals from your body leading you to feel pain. In time, as you follow this blog, I hope you will come to recognize the brain’s involvement in pain to the extent that pain science has unraveled the mysteries of pain through the mind-body connection. I encourage you to leave your comments and questions as you feel comfortable. Although I am a clinical pain psychologist, I am writing here about pain science and not about the treatment of anybody’s specific pains. Please do not leave highly personal information that you wouldn’t want other people to know. Your privacy is important to me. This blog is for information only and you should always check with your own medical or health care providers to see if/and/or how this information applies to you and your pains. If you are having suicidal thoughts, please immediately contact the National Suicide Prevention Lifeline at 1.800.273.8255 or call first responders in your area so that they can ensure your safety.