The Pain Puzzle

Chronic pain is the most prevalent and expensive public health problem in the developed world, but as a society we consistently fail to recognize the scale of the public health issue. Society has a unique and complex relationship with pain, not seen with other illnesses. No one ever said “no cancer, no gain”, but we persist in a belief that pain makes us stronger. We haven’t declared a “war on pain” or launched a “moonshot to cure pain”. Politicians do a lot of saber-rattling about how they are going to tackle the opioid crisis, but I have yet to hear them suggest that we fund more pain research to develop alternative therapies.

When I think about patients I treated 25 years ago, the reality is that there is little I could offer them now, that I couldn’t back then. Pain research hasn’t received the attention and funding to make the breakthroughs that have been made in other fields, and we still have a lot to learn before we can make substantial advances in managing pain.

My lab asks the question: “Why are people so different in their responses to pain?” We know from centuries of clinical experience that the same painful event causes dramatically different responses in different people. We already know that there are many different characteristics that determine an individual’s pain sensitivity. There are well-documented gender, ethnic and age-related differences in how we respond to pain. A handful of genes have been consistently associated with pain sensitivity, and a large number of psychological factors have been shown to have an impact.

The biopsychosocial model suggests that the experience of pain is sculpted by complex and dynamic interactions among biological, psychological and social factors. My team and I aim to dig deeper into these interactions in clinical studies. For example, African–Americans with osteoarthritis have more pain and disability compared with non-Hispanic whites with the same condition. We are studying social and environmental factors, their impact on biological processes like inflammation, and how that may change how the brain responds to pain. We’re trying to put all the pieces of the jigsaw puzzle together and get the complete picture of why certain groups differ in their response to pain. For public health, it’s useful to know who is at risk for more frequent and severe pain. At a more mechanistic level, those group differences reflect underlying differences in biopsychosocial processes. If we can trace the changes back to more specific mechanisms we may make discoveries that could help treat pain in the long term.

I do all my work in human studies. The biological factors are straightforward enough to address in preclinical research, but the psychosocial factors are much more difficult. To see why, consider one of my patients from 25 years ago. In his mid-40s, he was an iron worker who had injured his back at work and undergone multiple back surgeries. He had since suffered a myocardial infarction and developed an anxiety disorder after almost falling to his death from a skyscraper. He was functionally illiterate and struggling financially since his pain left him unable to work. How does one model that in a laboratory?

One of the first conversations that clinicians have with chronic pain patients is often to tell them that we are not going to be able to fix the pain, though we hope to manage it so they can have a good quality of life. Our goal is to reduce pain, and it may be that in some cases that is all we are ever able to do. But that doesn’t mean that we should just give up, shrug our shoulders and say, “Chronic pain is a part of life.” I think we can do much better than that.

The growth in our understanding of the neurobiology of pain serves as a great foundation for developing new approaches and new therapies. There is frustration that many of the targets that looked so promising haven’t worked out – frustration felt by researchers, patients and healthcare providers alike. But that is a problem that confronts every field – cancer remains the second leading cause of death in the US, despite enormous investments in research funding. They have had many more failures than successes, but their successes are saving lives every day.  The pain field already has really smart and dedicated people, who are changing how we understand pain. With more funding and more researchers, I think we would make significant inroads that could transform pain treatment and improve quality of lives for tens of millions of sufferers.

In the meantime, it’s important to remember that there are safe and effective therapies currently available that can reduce pain, improve function and boost quality of life. But many patients are not getting the best therapies for their needs, either because they cannot access care, or because their providers aren’t aware of all the options available. There would be an immediate and dramatic public health benefit if we could get the right therapies to the people who need them on a consistent basis.

"Crossing the Threshold Basic and clinical researchers must join forces to fight pain"      Michael Gold

"Growing Pains"    Suellen Walker

"The Mouse Trap"      Jeffrey Mogil