How your body and brain construct chronic pain

Wearing a cast, taking painkillers and receiving a warning to be more careful often put people on the quickest path to recovery from a broken arm. But that path can be longer when an illness isn’t as visible: A series of mysterious stomach aches or sporadic painful migraines are harder to explain. According to the Centers for Disease Control and Prevention, 24% of U.S. adults suffered from chronic pain in 2023. Yet despite its frequency, many doctors and their patients still struggle with being able to simply identify what hurts and fix it. In his new book, Tell Me Where It Hurts: The New Science of Pain and How to HealPain specialist and psychologist Rachel Zoffness explores how our bodies experience pain and how we can better understand, and even control, our responses.

Scientific American spoke with Zoffness to explain why we experience pain, both acute and chronic, how potential factors cause it, and what treatments are emerging.

[An edited transcript of the interview follows.]

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You wrote that you started studying pain because you were afraid of it. For what?

I think pain is a frightening experience. Evolutionarily, it’s meant to be! Pain is designed to get your attention so you stop doing what you’re doing, get help, and change your behavior so you don’t die. When I was trying to figure out what I wanted to do with my life, I took my first neuroscience class my freshman year, with a neuroscientist named Mark Bear, and he was talking about the science of pain. He explained how it lived at the intersection of medicine, biology, neuroscience and psychology – and I was hooked. I was afraid of pain, but it was at the intersection of everything I wanted to do.

You mention in the book that many medical schools don’t offer courses dedicated to pain, and those that do often only dedicate a few hours to it. Why isn’t pain addressed in more depth?

When I started studying pain and started understanding that it was biopsychosocial, that’s now my favorite word. This means that pain lives at the center of biological factors, psychological factors and sociological factors. When I’m in pain, I’m told to go to the doctor and they examine the part of my body that hurts. This is usually the end of the conversation. No one asks me about sleep, diet, stressors, or trauma history, and we’ve known for decades that all of these factors affect our pain.

I found that 96% of medical schools in the United States have no required courses dedicated specifically to pain. The 4 percent of medical schools that offer pain education courses primarily teach the biomedical model, which is the error that [17th-century French philosopher and scientist] Descartes did in his decisive text Meditations on the First Philosophyin which he separated the spirit from the body. We have known since the development of pain control theory in 1965 that pain is not limited to the part of the body that was injured.

You cover many case studies in the book, but the one that comes to mind is that of a young child who lost a limb after a traumatic accident involving fireworks. How did this case study reveal the biopsychosocial factors you focused on?

It was a kid named Mateo, and he was suffering from terrible phantom limb pain. Phantom limb pain occurs when a person feels terrible pain in a missing part of the body: it felt like his hand was spasming and clenching all the time, but he had no hand. Pain is ultimately constructed by the brain, and some of the best evidence neuroscience has is phantom limb pain. If you can feel terrible pain in an arm that is no longer attached to your body, that tells us pretty definitively that the pain must be building somewhere else. So while the brain is important, when you have chronic knee pain, the only person you see shouldn’t just be the knee specialist.

It’s interesting how your book balances lifestyle changes without saying, “The pain is just in your head.” » So how do we explain this to people without ignoring their pain?

In the book, I broke down the neuroscience of each biopsychosocial factor. For example, humans are, by design, social animals. When we’re social, our brains produce the neurochemicals that help us feel better, like dopamine, serotonin, and endorphins, which are our natural painkillers. Former US Surgeon General Vivek Murthy did this incredible study on how loneliness is a huge predictor of chronic pain and illness and even shorter life expectancy. So there is a science that connects our social health to our physical health.

I wanted to map biopsychosocial factors in a way that removed stigma and highlighted that emotional health, social health, and environmental health affect our pain just as much as biology.

So why does our body bother to feel such pain? What is the evolutionary benefit behind chronic pain, in particular?

Evolutionarily, pain is meant to get our attention and save our lives. When it comes to acute pain, we want to listen for danger messages, for example if you suddenly feel terrible abdominal pain after eating a bad tuna sandwich, you better pay attention because you might have food poisoning. One way pain becomes chronic is through this process called central sensitization. And central sensitization is what it sounds like: “central,” meaning the central nervous system, and “sensitization,” meaning it becomes more sensitive over time.

Did you have a skill that you were bad at and you practiced it, and over time you became good at it?

Yes, like everyone, in 2020, I decided to learn embroidery.

The pathways in the brain are similar to the muscles in our body. When you use your muscles through exercise, they become stronger. So the more you embroidered, the stronger the embroidery path in your brain became. But the same goes for the pathway of pain through our central nervous system; it becomes big and strong over time, with practice and use. When this happens, our central nervous system is said to have become sensitive to pain.

But among the general public, the expression “being sensitive to pain” has generated a lot of stigma and misunderstanding. My goal in life is to explain pain with great hope.