And yes! There’s more to this series of posts on how I use a biopsychosocial model in practice!
Today’s post is about moving from a conceptual model to a practical model, or how we can use research in our clinical reasoning.
A biopsychosocial model (BPSM) as envisaged by Engel was a framework for clinicians to think about why this person is presenting in this way at this time (and what may be maintaining their situation), as well as what could be done to reduce distress and disability. Engel wanted clinicians to go beyond disease processes, isolated from the people experiencing them, and to explore aspects of how the person coped with everyday challenges (including health), the factors that influenced their decision that their health problem was indeed a problem, and the context of seeking healthcare. He wanted clinicians to be scientific about how they generated hypotheses which could then be tested in clinical practice, and ultimately confirm or disconfirm the contribution of that factor.
The “bio” aspect of pain (which is a contentious word – I’ll comment in a bit) involves disease processes, trauma, all the biological aspects prior to conscious awareness of the “ouch” we know as pain. Theoretical developments in this area include all the work being conducted in terms of understanding anatomy and physiology of the human body, from molecular study (information transmission from one neurone to another); detailed understanding of spinal cord mechanisms; of the role of glia; of inflammatory processes; of genetic and epigenetic changes; of relationships between blood flow to and from various parts of the brain; of biomechanics; of normal healing processes – and so on. There’s no lack of information being generated by researchers undertaking basic science about the biological mechanisms involved in our experience of pain. Because I typically see people with persistent pain that has been present for maybe 12 months or more (usually much longer than that), I rely on the work of my colleagues to make a good diagnosis. Most people have had more investigation than is probably helpful for them, and I think we can use Clifford Woolf’s broad mechanisms as a reasonable stance when considering an underlying mechanism involved in a person’s pain. Essentially he identifies four main mechanisms: nociceptive, inflammatory, neuropathic and what is now known as “nociplastic” (where the nociceptive system appears to have a problem with processing information).
Yes, we can argue that our current state of understanding is incomplete and there is more to learn, but by working from these basic mechanisms I think we can begin to work on the “bio” part of a biopsychosocial model with a degree of confidence. For my work, anyway, these mechanisms seem to provide a reasonable framework from which the “bio” part of management can begin.
But this is where many clinicians start – and stop. Directly treating, for example, inflammation, certainly provides a reduction in pain – for example, my partner who takes Humera for his ankylosing spondylitis. He no longer experiences inflammatory pain and as his CRP levels reduced, so too did his pain. We can see similar effects when someone has a grotty old hip joint replaced, which removes nociceptive input, ultimately leaving them with a shiny new and painfree hip (in most cases). But as my partner found out, having no pain doesn’t immediately change old habits.
His situation is a nice illustration of the interaction between a disease process which responded really well to a drug that eliminates inflammation, and his beliefs and behaviour which wasn’t changed. Let me explain – once his drug kicked in and he had no pain, he found it odd not to have to think about his pain when climbing hills. It took him about a month or two to fully return to hill climbing in the way he’d done before his anky spond started. That’s right – no pain for a month or two, but that long before he felt confident to go about his activities. And he’s not a man who worries much about his pain!
To add some theory to this, his beliefs (that if he climbed hills a full speed he would inevitably end up with a very sore back) led to him having learned not to go a full pace (through both classical and operant conditioning). We could call this “pain-related fear and avoidance” – or “fear avoidance”. This is one theory that has been extensively researched, and we can integrate the hypotheses generated from this theory into our understanding of why my partner initially had some hesitation about climbing hills. Flowing on from this, we can consider treatments that have been found useful to address his hesitation.
The first treatment could be “explaining pain” to him. Now that wasn’t useful in this case because – oh yeah – his pain had gone! And although he knew his inflammatory pain wasn’t going to harm him (otherwise he’d never have been a high country fire fighter for 20 years despite his anky spond!), he didn’t like the after-effects of aggravating his pain. What helped was addressing his anxiety about the potential for a big flare-up – and this was primarily about beginning at a level that was just beyond his “normal” hill climb, and gradually progressing.
This superficially looks like “exercise” – but it’s exercise with a twist. My partner is as fit as a buck rat. His cardiovascular fitness was fine. Gradually increasing his hill walking wasn’t about increasing fitness – it was about helping him approach an activity that he was a tad concerned might flare his pain up, leading to a rotten night’s sleep (as it had in the past). In fact, this “treatment” was almost all about reducing avoidance by exposing him to things that increased his anxiety just a bit – enough for him to establish that the rotten sleep consequence didn’t happen.
So a biopsychosocial approach to his recovery involved the biological which quickly resolved his pain but left him with some concerns (reasonable ones I think) about pushing himself too hard. Addressing those concerns by taking a theory developed originally from phobia research, applying it to his situation and developing a treatment based on this theory, has led to his return to full participation. Using research-based information to address another part of “why is this person presenting in this way at this time, and what might be maintaining this situation” involves thinking beyond the disease process, and into understanding the problems the person identifies. It means thinking beyond a single discipline. It means reading widely and thinking creatively. That was a good part of Engel’s original proposition.