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World of hurt

Our experience of pain not only depends on physical trauma, it is also affected by cultural background and optimism. So, now we know that, what can we do to alleviate the suffering, asks Vanessa Collingridge

 

It can start with a simple injury. You hurt your back playing sport or have an accident at work and steadily the pain grows until it pervades every moment of your waking day and robs you of sleep. Exhausted and in agony, you go to see your doctor, who prescribes painkillers and perhaps even an operation to resolve the trauma. But the treatment doesn’t work. Days become weeks and weeks become months – and still there’s no end in sight. You are now living with chronic pain.

You’re not alone.

Research figures vary but it’s estimated that between 10 per cent and 40 per cent of the adult population in Hong Kong suffer from chronic pain that significantly affects their quality of life. Not only does the pain affect what people can do physically, it is also recognised as a major cause of anxiety and depression, even suicide. And the problem is not just personal. As well as costing billions in lost productivity and welfare payments, recent figures from the World Economic Forum suggest that almost one in 10 Hongkongers now provides informal care to a frail or sick relative and the lack of state support for the chronically ill means many of these carers will eventually have to give up their job, too.

Of course, pain is not necessarily bad. It can warn us of injury or disease, allowing us to seek treatment before the condition worsens; it can also be protective, teaching us to steer clear of whatever it was that gave us the pain. So when does pain become a problem – and why is it so hard to treat?

Dr Cheung Chi-wai is the director of the University of Hong Kong’s Laboratory and Clinical Research Institute for Pain, set up two years ago to foster an interdisciplinary approach among scientists, medics and psychologists working in the field.

“In medicine, we talk about two types of pain: acute pain is related to an initial trauma but if that continues for more than three months, we say that a patient now has chronic pain, which is not only more difficult to manage, there is also greater harm to that pain for the sufferer,” he says.

“In the old days, we used to think that pain was just the body’s reaction to tissue damage, a purely physical response, but we now realise that explanation is way too simplistic and that emotional, cultural and psychological factors make a huge contribution to a person’s experience of pain. The trouble is, that makes the experience of pain highly individualised and harder to understand, let alone resolve.”

A quantum shift in thinking came about in 2002, at a European conference on pain. There, experts from around the world joined together and announced that while pain had always been regarded as a symptom of disease, chronic pain had no obvious cause and should therefore be regarded as a disease in itself.

“This was a really important conceptual leap to make,” Cheung explains, with a passion still evident more than a decade later. “It not only widened our field of inquiry, classing chronic pain as a disease allowed more resources to flow in to improve research and clinical care.”

Since then, the study and treatment of pain has become more nuanced, attracting interest from an increasingly wide body of disciplines, including physiology, genetics and neurology. But equally important were the advances in technology that gave rise to ways of studying pain in the brain.

Nick Rawlins is professor of experimental psychology and a provice- chancellor of the University of Oxford, in Britain. One of his main research interests is in the way humans respond emotionally to pain.

“Chronic pain is – by definition – where we as doctors and scientists have failed. We’ve failed to deal with the initial pain and then failed to manage it in the longer term, so really it’s an area that’s ripe for another approach – and psychology has a lot to bring to the table.”

Rawlins’ original research dealt with animals and the neural basis of their anxiety.

“I’d worked for a long time with rats, using the model of issuing a mild electric shock – just a prickle, really – to see what affect this had on their behaviour. Basically, we wanted to see how pain and the threat of pain affected their decisions whether or not to do something – we gave them an unpleasant stimulus and monitored their response. These kinds of experiments taught us a lot about the brain systems underlying anxiety, fear and pain. But we didn’t have the tools to extend the work into studies of humans; at that time, we couldn’t figure out how far human responses to pain are driven just by pain intensity and how far they are driven by the memory of previous pain, and anxiety about what might happen next.”

Part of the answer lay in existing scientific understanding about the nature of the brain. Ever since the case of Phineas Gage we’ve known that different parts of the brain have different functions. On September 13, 1848, the unfortunate Gage was working on a railroad in the American state of Vermont when an explosion drove a metrelong, 6kg iron rod straight through his cheek, behind his left eye and out through the top of his head, destroying much of his brain’s left frontal lobe – and landing some 25 metres away. Incredibly, Gage not only survived but within a few minutes was able to walk, talk and then sit up on the almost mile-long cart-ride into town. He survived for almost 12 years, dying in 1860 after a series of convulsions.

Friends and colleagues of Gage, however, reported that his personality had changed radically. He seemed to have gone from being polite, reliable and shrewd before his injury to being foul-mouthed, unreliable and not at all shrewd after it – supporting the idea that the frontal lobe of the brain is responsible for not only organisation and planning but also plays a role in the emotions.

Gage’s case cemented the idea of using brain-damaged patients to find out more about which parts, or modules, of the brain were responsible for different abilities and behaviours – and over the next 150 years, the new discipline of neuroscience matured and thrived.

However, when it came to understanding why pain hurts so much – and why it can sometimes outlive the original trauma – the question still remained: what else is going on in the brain? And how can you separate out all the factors that make up our experience of pain?

The breakthrough finally came with the advent of functional magnetic resonance imaging (fMRI) – a technique that uses powerful magnets to measure blood flow. This allowed scientists to look inside the brain, module by module, and see the areas that were lighting up in response to a particular stimulus.

“Quite simply, it gave us the capacity to see – trial by trial – what was going on in the brain,” says Rawlins. He had long suspected that chronic pain was made up of physical and psychological components – and that these combined to make the experience of pain even stronger – and also harder to treat. So, with his colleagues at Oxford, he designed a study using fMRI to try to separate the anticipation of pain from the experience of pain. Twelve people underwent a series of experiments using painfully hot and non-painful warm stimuli, with different coloured lights alerting them to which type of heat was coming next. By manipulating the lights to occasionally give false warnings, Rawlins was able to work out which areas of the brain lit up to the painful heat itself and which lit up to the anticipation of the painful heat.

“I’d placed a big bet on this study. It was all based on good evidence but, still, I might have been wrong so I was hugely relieved when we got the data back: the results were amazing. We’d succeeded beyond our wildest dreams. We could clearly see that pain and anticipated pain lit up different circuits in the brain – opening up the possibility of two separate targets for treatment, one dealing with the physical pain itself, the other trying to mitigate the fear of pain that seems to be learned through past experience. Conceptually, that’s very, very important – the two circuits are related, but subtly different and so can give us a two-pronged approach for dealing with chronic pain with pharmacological drugs in combination with psychological therapies.”

So what does all this mean for those suffering from the debilitating disease of chronic pain? For Rawlins, his research underlines the synergies that can be gained by taking a more integrated approach.

“As well as using drugs to specifically target the anxiety associated with pain … cognitive behavioural therapy, in particular, is very effective in dealing with things like anxiety and depression that we now realise are so much part of chronic pain, and this seems to be even more effective when it’s combined with mindfulness, which seems to work by interrupting negative thoughts. I certainly think there are further riches to mine there, along with acupuncture and also hypnotism, which is also giving some very interesting results.

“I think one of the most important lessons is that we should be maximising the psychological content of conventional drug treatment as we know that the way in which you give a drug will affect its pharmacological properties. We already recognise that there’s the so-called ‘placebo effect’, so we should be using this to make existing pain-relieving drugs more effective. We know that if you’re going to have a tooth extraction and you say, ‘I’ve got a great experimental compound here and I’m extremely confident that it will significantly reduce your pain and improve your recovery!’ then it does indeed reduce your pain and improve your recovery, whereas if you say to a patient, ‘Well, I have a drug here that might perhaps help so at least give it a try,’ then the placebo effect will be lower. Now, you could just call this having a good bedside manner but I think there’s more to it than that.

“We know it’s crucial to treat pain quickly and effectively, so early intervention is really important. We also know that if we brief people properly about their likely recovery after an operation, they will get better more quickly. But what this also means is that if you, as a doctor, race through the explanation to your patients because it’s Friday evening and you want to get home, then you’re likely to end up with 40 per cent higher bed occupancy in your wards, so it’s vital that we train doctors to recognise the importance of keeping their patients properly informed.

We’ve already seen the benefits of patients feeling in control with the use of self-administered pain relief pumps – their pain control is better and their dose is lower than if you have to wait for a nurse or doctor to give you your medication. We now need to do the science to back up why all these anecdotal things work so that we can make the most of the tools already at our disposal.”

But while the scientists are getting better at sharing best practice ideas and data, there are some clear problems with simply importing ideas from East to West, and vice versa.

“There are some very real cultural differences in the way Chinese and Westerners will react to chronic pain,” says Samuel Ho Mun-yin, a professor of psychology at the City University of Hong Kong and a practicing clinical psychologist specialising in emotional resilience and reactions to trauma. “Chinese culture expects the family to support a relative who is suffering but rather than helping, this can actually increase anxiety – and with it, pain – as the patient feels a burden to their family members. It’s very different from Western culture, where the message tends to be that the state will provide your care but you need to stay strong and look after yourself.

“Likewise, there are differences in the way we conceptualise chronic pain. In traditional Chinese culture and medicine, we always see medical problems in a holistic way, with mind and body components being part of one system. Chinese people are therefore more receptive to the psychological component of pain than in the West, which takes a more Cartesian approach that splits the mind from the body. This has an important bearing on the types of treatment we offer to the different groups and also the way we apply research from one cultural context to another – and it’s something that we need to take seriously as things like social support and environmental factors will affect the pain outcome for a patient, and with it their quality of life.”

Cheung agrees: “I don’t think there’s been nearly enough research on cultural differences in the way people relate to pain. Australian studies suggest that when patients are well educated about their medical procedures and the expected outcome, they are more willing to admit that they have pain and need drugs, whereas Chinese often think it’s good to tolerate pain as that means you’re strong. Trouble is, we know that it’s really important to get early intervention after trauma from injury or an operation to protect the central nervous system and prevent pain becoming chronic, so the Chinese way is not sensible at all. But until we understand more about the cultural differences, we can’t properly target the best care to each group. You just can’t have a one-size-fits-all approach to pain management – it has to be based on individual need or it just won’t work.”

One encouraging area in chronic pain research is “hopefulness”, which is being explored by Ho and his team at City U and in hospitals across Hong Kong.

“While personality does not seem to be very related to pain,” he explains, “there is good evidence to suggest that if you’re sad, then your pain tends to intensify, whereas more optimistic or hopeful people tend to have a better and more adaptive reaction to the pain experience. We can use this idea to inform treatment. For example, if you have a fear of pain, we can induce some positive emotions (for example, by recalling pleasant memories) to make you less negative and this will actually reduce your pain. In clinical psychology, this simple technique is sometimes referred to as ‘positive emotion induction’ or PEI. We’re only just beginning to realise the importance of resilience but the good news is that it’s something that can be learned.”

Cheung is conducting a study to update figures on the incidence of chronic pain in Hong Kong: “I’m expecting there to have been an increase since the original research was done, in 2001. Just look at what’s happening to us – we’ve got a high-stress, low-exercise culture developing, set in the context of poor environmental conditions but, most significant, I think, is the fact that we’ve also got an ageing population with all the chronic pain from cancers and back and knee problems that come with getting older. It’s a serious and growing problem in the world in general but particularly worrying here in Hong Kong, where we simply don’t have the resources in the health service to cope. The number of patients is rising and we just don’t have the money, or [enough] sufficiently trained doctors, to help them.

“It’s frustrating that people still don’t think of pain as a serious disease. We desperately need to raise awareness, to make the government sit up and take notice, and to attract the large donors who’ve done so much to improve the lives of cardiac and cancer patients – but pain seems to have a PR problem.

“To my mind, having adequate pain relief is not a privilege, it’s a human right. Nobody should have to live in pain – and there is so much more that we can and should be doing. But in the meantime, what’s important is for sufferers to realise that there are things that we can do now to improve their condition, so ask for help as soon as possible, and don’t ever suffer in silence.”

 

Professor Nick Rawlins is scheduled to launch the Hong Kong Café Scientifique tomorrow, with his talk on “Pain and the Brain!”. Café Scientifique is a global network of science cafes where, for the price of a cup of coffee or glass of wine, you can hear top scientists give a short talk and answer questions on subjects ranging from astronomy to zoology. Tomorrow’s event will take place at the Hong Kong Maritime Museum, Central Ferry Pier 8, and doors open at 7pm. For news of future Cafés, e-mail cafesci.hk@gmail.com and write “subscribe” in the subject line.

 

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