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APS Bulletin • Volume 19, Number 2, 2009
Translational Pain Research
Christine Sang, MD MPH, Department Editor
A Biopsychosocial Model Discussion: From a Fragmented History to a Streamlined Future
Jane Martinsons, Staff Writer
Editor’s Note: This article is the next in our series focusing on successful translational research in pain. Using a more expanded definition of translational research to include explanatory and/or descriptive models and methods of treatment that have a solid research basis and have been translated, researched, and now routinely applied to clinical pain, the biopsychosocial model is certainly one of these success stories.
The APS Bulletin recently spoke about the past, present, and future of the illness model with the following individuals who have pioneered and led this very important transitional research process: Robert Gatchel, PhD ABPP, of the University of Texas in Arlington, TX, and John D. Loeser, MD, and Dennis Turk, PhD, both of the University of Washington in Seattle, WA.
Past
Gatchel: It’s a fragmented history. Medicine in the 1970s was very traditional and slow to move. There was increased awareness that things like smoking and cardiovascular disease were major causes of mortality in this country and that lifestyle changes were really important in terms of weight loss and exercise. The fields of health psychology and behavioral medicine grew at this time, as did the pain field. In 1977, George Engel introduced the concept of illness behavior and called for a new medical model, indicating that this was more than just a physical problem. Years earlier, Bill [Wilbert] Fordyce, PhD, was the first to introduce a specific psychological process involved in chronic pain, operant conditioning, and to indicate that reinforcement contingencies were quite significant in maintaining certain types of chronic pain behaviors.
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“Different specialists in anesthesiology, gastroenterology,
and cardiology now talk about the
BPS model. Despite George Engel’s initial call for
it in 1977, they now see how the model is applied
and conceptualized. The proof is in the pudding;
it makes sense and is basically translated to realword
efficacy. I believe it was our work in the pain
area that really brought it to the forefront.” —Bob Gatchel, PhD |
By the early 1980s, Drs. Fordyce and Loeser started to pull away from the traditional medical model toward a more comprehensive behavioral medicine model. Also at that point, techniques such as biofeedback and stress management were introduced, and there was a lot of research showing how psychosocial factors such as anxiety affected pain threshold. During the 1980s and 1990s, Dennis Turk and I started using the term biopsychosocial to emphasize that pain is just not a biological problem, but that you have to deal with the psychosocial components, especially when pain becomes chronic. Interdisciplinary pain management programs based on a BPS model integrated both pure science and clinical applications. In 1985, Tom Mayer, MD, and I introduced the notion of functional restoration. Basically, we demonstrated that an interdisciplinary team comprising a physician/nurse team, a physical therapist, an occupational therapist, a psychologist, and a psychiatrist needed to focus on every aspect of an individual with pain—not only the pain itself—and deal with all of them simultaneously.
Loeser: How was the BPS model originally applied to clinical pain? Actually, I would turn it the other way around: Dr. Fordyce’s pain as learned behavior came long before Dr. Engel’s BPS model. Dr. Fordyce’s first paper on operant conditioning in pain in 1968 preceded the widespread recognition of Dr. Engel’s BPS model. Although not termed biopsychosocial, Dr. Fordyce’s original work directly challenged the biomedical model by taking into account the role that factors outside the patient, including environmental factors, play in pain. His approach, however, never had the panache of Dr. Engel’s later BPS model, which spread rapidly among intellectual circles throughout the medical community. I developed a BPS model based in large part on Dr. Fordyce’s concepts, but it never really took hold outside the pain community.
There’s no question in my mind that the BPS model has played a very important role in pain by calling people’s attention to the fact that the biomedical model, which basically ignores the fact that human beings are human, doesn’t adequately explain pain behavior.
Turk: There have been parallel advances both in the biology and physiology—neurophysiology of pain from the basic science perspective—and there have been parallel developments in the areas of psychosocial factors as they relate to the experienced perceptions, response to pain, and response to treatment. These are two parallel tracks that evolved and built off of each other. Both sides, biological and the psychosocial, have learned from each other.
A Paradigm Shift?
Gatchel: The shift from a pure traditional biomedical approach to a BPS approach was really a major paradigm shift in science and medicine.... The biomedical approach served its function; that’s all we knew at that time. It had a big grip on medicine until illnesses became more chronic and the prevalence of pain and chronic pain problems continued to grow. Then, that old system didn’t work. If you operated on a person many times, he or she didn’t get better but instead developed more pain problems. With chronic pain, a whole new approach needed to be taken.
Loeser: This was a major paradigm shift. The Gate hypothesis, published in 1965, basically said that the perception of pain was modulated by both afferent and downstream activity from the brain. That’s sort of a biologic way of saying affective, emotional, and environmental factors influence the perception of pain. The Gate theory laid the groundwork for Dr. Fordyce to argue that environmental factors influence the way people think and feel, and that is what gets the downstream modulation altering the perception of pain. It fits together and that is how we got to the popularity of the BPS model, although there were components that preceded it that played an important role.
Present
Turk: Today, psychosocial factors can be the best predictors of how well people respond to treatments such as surgery or the likelihood that an acute injury will develop into a chronic problem. It’s drummed into people’s heads that we can’t rule out the importance of psychological, social, and economic factors in what’s happening on a physiological basis. The insurers are seeing it; the research demonstrates this to them. National Institutes of Health (NIH) is seeing it. There is a movement in the direction of accepting this.
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“Right now the NIH is funding grants at the ninth percentile. What that means is that many very
good proposals are not funded, and that’s a killer. It’s demoralizing, but it’s not unique to the world of pain by any means.” —John D. Loeser, MD |
Loeser: The BPS model is the foundation upon which most contemporary pain research is built. For example, it’s become widely recognized that patients’ fears about what will happen if they move or use a [body] part that hurts is a major determinant of outcomes for therapy. More and more, funding agencies and surgeons themselves are saying that we need to get a psychological assessment before making decisions about surgery, which means they recognize that something, [for instance,] other than the patient’s back plays a role in the complaint of back pain.
Insurance: A “Swinging Pendulum”
Turk: In the 1960s, when Drs. Engel and Fordyce were talking about and developing this model, there was a lot of distress in the insurance industry because they had all these people with pain problems and they didn’t know what to do with them. All of the sudden, researchers said they had a new treatment model, so there was a lot of enthusiasm among insurers who thought their prayers had been answered. That was before they realized that these programs were expensive, they didn’t have much outcomes data, and there were still many people with pain problems. So the pendulum swung in the other direction. “Let’s go back to treating these things and forget all the psychological stuff,” the insurers said. “We’ll fix the broken body parts and everything will get better.” The reality was that that didn’t work. Now I’m starting to see the pendulum swing back, but [we have] very expensive treatments. Implantable devices—including spinal-cord stimulators, drug delivery systems, and morphine pumps—cost between $40,000 and $60,000—and that’s just for the procedure itself, not the follow up.
Gatchel: In the 1980s and 1990s, not everyone had the capability or resources to put together a true interdisciplinary program. There is a lot of overhead involved with having multiple disciplines under one roof, so it was difficult getting insurance authorization. Places struggled with that, but they continued to embrace the concept because the data being published demonstrated its efficacy. That struggle still continues today and insurance companies are the chief culprits of it.We keep publishing results demonstrating efficacy, but insurers are very reluctant to cover treatment. There is no doubt it’s the most effective treatment approach for chronic pain.
Insufficient Funding for Pain
Loeser: There’s a huge problem in the NIH when it comes to pain. The bottom line is there is not nearly enough funding. I served 4 years on the Advisory Council of the National Institute of Neurologic Disease and Stroke, and they didn’t like me very much because I kept saying to them, “The legislative mandate of the NIH is to reduce the burden of illness on the American public.” By far the most common neurologic disorder in the American public is chronic pain, and they do virtually nothing in the realm of chronic pain research—it is a fraction of a percent of their funds. There’s no question that the pain community feels that the NIH has been woefully inadequate in addressing the problems of chronic pain.
Turk: Actually, there is a little bit of interest in combination treatments at NIH, as seen in their latest request for challenge grant submissions. For the first time—that I’ve seen—about a dozen of 200 suggested areas for applications targeted combination treatments. NIH has never been interested in clinical trials; it’s far more interested in facing mechanisms underlying these processes. I think the word at NIH may be that we need to do something in this area.
Future
Gatchel: Brain imaging is a big area now. We are gaining a better appreciation of areas of the brain that are responsible for different brain syndromes. Clinicians are using, vis-à-vis a biofeedback-type paradigm, real-time imaging to have patients modify those areas—to either turn them on or off, depending on where the pain centers are. That’s very exciting. There also are a lot of new advances being made in genetics; we’re just experiencing the tip of the iceberg. If we can do genetic screening more easily in the future, hopefully we’ll be able to more specifically prescribe certain drugs that will work better for certain people.
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“We call it ‘chronic’ pain because there is no cure,
despite big advances in neurophysiology and
pharmacology. Some new advances in opioid
variants reduce the pain, but they don’t eliminate it
and cure the problem. Just like diabetes, people have
to learn a lot of self-management and self-control.” —Dennis Turk, PhD |
Turk: We’re going to see a lot more predictions of who responds to different kinds of treatments. It’s not just genetics, however; there are also individual variations we’re seeing in coping patterns and in the types of symptoms onset. I work in fibromyalgia, which tends to be a repository for a combination of different signs and symptoms. We have tended to treat these patients as a homogenous group, but our research is showing there are different characteristics of patients that may be important as we consider the best treatment. In the future, we are going to see combination treatments and responder analyses to find out the physical, psychosocial, and behavioral characteristics of patients who respond to a given treatment. It will be clinically more effective, and definitely more cost effective. How far off are customized treatments? Close. I actually have NIH grants to look at this.
Loeser: In this and every other area of medicine, genetic issues are going to come to the forefront. We’re beginning to learn, for example, that genes determine whether or not you respond to narcotics, whether it’s metabolizing the drug or binding the drug. We’re going to come to an era soon where we will conduct genetic analyses of patients to make predictions as to outcome and to determine what kinds of therapies are going to be relevant. As we learn more about what genes do, what genes there are, and what different alleles at the same locus do in response to various kinds of treatment, it would not surprise me at all if in the near future we will literally have patients tell us their genome and we’ll tell them what drug to use, which is a big improvement. Ironically that is very biomedical, not biopsychosocial. But just as we develop genetic understanding, we are also going to continue to develop an ability to diagnose and predict outcomes based on psychosocial factors.
Message to APS Colleagues
Gatchel: Push for the dissemination of the BPS model whenever you can. Mention it to government officials at state and [national] levels. Talk to medical colleagues to let them know there is a wealth of good scientific research out there that they can gather articles and demonstrate to it. Also, be very aggressive with insurance companies. It takes time, but we all need to keep pushing in that direction.
Turk: We tend to forget that people have two things: They have a medical history and they don’t live in isolation; they live in a social context. We need to pay more attention to how people and their significant others affect each other. The ‘social’ in BPS tends to start with a small s, but let’s not forget that social factors are very important. The ‘bio’ ‘psycho’ and ‘social’ need to be in balance if you’re to have optimal outcomes.
