Читать книгу The Sickening Mind: Brain, Behaviour, Immunity and Disease - Paul Martin - Страница 11

The misleading distinction between illnesses that are ‘physical’ (in other words, real) and illnesses that are ‘psychological’ (and therefore by implication not real) is starkly illuminated by the furore over chronic fatigue syndrome, otherwise known as myalgic encephalomyelitis (ME), post-viral fatigue syndrome or, if you read the tabloid press, yuppie ’flu.

It is with some trepidation that I thrust my head into the lion’s den of controversy over the causes of chronic fatigue syndrome. Fierce arguments continue to rage and the medical establishment has yet to reach any consensus. In excess of eight hundred scientific publications have been devoted to the subject and the picture changes almost weekly. Those who suffer from the illness often have passionate views about its origins and anyone who gainsays them is asking for trouble.

The debate about chronic fatigue syndrome is relevant here because it exemplifies the false dichotomy between ‘psychological’ and ‘physical’ origins of illness. Throughout the controversy runs a seductively misleading vein: the implicit assumption that the illness must be either physical or psychological in origin. But first, what exactly is chronic fatigue syndrome?

Since 1988 the term chronic fatigue syndrome (CFS) has been used to describe a debilitating illness of unknown origin that has persisted for at least six months. As you probably know (for it is often in the news) CFS is characterized by a dreadful, disabling tiredness that is made worse by any physical exertion. This fatigue is accompanied by a motley assortment of other symptoms, including general malaise, intermittent fevers, pains in the joints, stiffness, night sweats, sore throats, poor co-ordination, visual problems, skin lesions and sleep disorders.

As if that were not enough, many CFS sufferers also experience psychological problems such as severe depression, forgetfulness, poor attention and lack of concentration. CFS can persist for years and it ruins the lives of those afflicted. Often they will be forced to give up work. Sufferers may show a measure of improvement over time, but the majority remain unwell for several years.

Cases of CFS have been reported in most industrialized nations including Britain, the USA, Canada, France, Spain, Israel and Australia. Sufferers tend to be young adults between twenty and fifty, though children can also be affected. According to the American Centers For Disease Control and Prevention, more than 80 per cent of CFS sufferers are women, most are white and their average age when the illness develops is thirty. Another common factor is that sufferers usually report having contracted some form of viral infection not long before the syndrome manifested itself.

As yet, no one has come up with a truly effective remedy for CFS. None of the drugs that have been used to treat the syndrome is of proven effectiveness and some may do more harm than good.

CFS, as currently defined, is a relatively recent phenomenon. (But then, so is AIDS; the fact that a disorder has only recently been recognized and defined does not detract from its reality.) Records of vaguely CFS-like syndromes, involving severe fatigue, muscle pains and other symptoms, date back at least two centuries. The medical history books, however, contain nothing that can be unequivocally compared with CFS before the second half of the nineteenth century, when neurasthenia became a common diagnosis. Incidentally, cultural stereotypes about the sort of person who was susceptible to neurasthenia were as strong in the nineteenth century as they are now about CFS. Neurasthenia was said to be a disease of affluent middle-class women, in much the same way that CFS has been inaccurately portrayed by the popular media as ‘yuppie ’flu’, a disease of affluent thirtysomething professionals.

It was not until the first half of the twentieth century that reports of a disorder corresponding to CFS started to accumulate. The first well-documented outbreak of a CFS-like disorder occurred in the 1930s in the USA and was attributed to a mystery virus. A similar mystery ailment afflicted the staff of a London hospital in 1955, in what became known as the Royal Free epidemic. The sufferers experienced persistent muscle pain and fatigue. To begin with the syndrome was referred to as benign myalgic encephalomyelitis. By 1956, however, it had proved to be anything but benign, and so it became known simply as myalgic encephalomyelitis, or ME.

Since they first appeared on the medical map, CFS-like illnesses have gone by a baffling variety of names including epidemic neuromyasthenia, neurasthenia, Iceland disease, Royal Free disease, atypical poliomyelitis, fibrositis, fibromyalgia, post-infectious neuromyasthenia, post-viral fatigue syndrome and myalgic encephalomyelitis. It is not certain that all these illnesses have been identical with what is now referred to as chronic fatigue syndrome. An analysis of twelve well-documented outbreaks of CFS-like disorders found they differed in various respects, notably with regard to neurological problems.

Now we come to the real meat of the problem. No one yet knows for certain what causes CFS. The arguments continue to rage and there are major divisions of opinion within the medical community. But what characterizes the whole debate – especially as it is portrayed in the popular media – is the implicit distinction between physical causes, which are held to be genuine, and psychological causes, which are held to be suspect.

With a few honourable exceptions, expert opinion on CFS divides neatly into two opposing camps. In one camp are those who maintain that CFS has a physical cause such as a virus or an immunological disorder. According to this view, the depression and other psychological symptoms that characterize CFS are consequences rather than causes of the underlying physical disorder.

In the opposing camp are those who argue instead that CFS is fundamentally a psychological disorder. According to this view, the physical symptoms such as exhaustion, muscle pains, fever and malaise, are manifestations of an underlying psychiatric problem.

Which view is correct? You may not be surprised to find that both are at least partially true. Many CFS sufferers have symptoms that match the diagnostic criteria for psychiatric disorders and organic disease. The evidence is undoubtedly complex and equivocal but it points towards one conclusion: that chronic fatigue syndrome has both physical and psychological components. Let us examine some of this evidence.

Most cases of CFS are preceded by a viral infection of one kind or another, and there have been repeated suggestions that a virus might lie at the root of the syndrome. For a long time the prime candidate was the Epstein-Barr virus, a member of the herpes virus family which is also responsible for glandular fever. During the 1980s chronic fatigue syndrome was widely referred to as ‘chronic Epstein-Barr virus infection’, as though its viral origins had been firmly established. Other candidates have included retroviruses (of which HIV is an example) and polio-like viruses called enteroviruses.

There is as yet no conclusive evidence to support the viral theory and it has therefore fallen out of favour. But even if viruses are not the prime cause of CFS, it remains highly plausible that a viral infection might help to trigger or precipitate the syndrome when other causal factors are also present.

Several other physical causes besides viruses have been proposed. One theory maintains that the primary symptoms of CFS are produced by hyperventilation – that is, abnormally rapid breathing. The evidence, however, is once again scant. Only a minority of CFS sufferers hyperventilate. On another tack, research at Johns Hopkins University in Baltimore has indicated that certain types of chronic fatigue (though not necessarily all cases of CFS) might result from abnormally low blood pressure. Yet another suggestion has been that CFS stems from a form of neurobiological disorder. One study revealed that more than a quarter of CFS patients had abnormal brain scans, and subtle changes have been found in the levels of neurotransmitter substances in the brain.

At present, the most favoured physical theories about the origins of CFS revolve around the immune system. There is growing support for the view that the symptoms of CFS result from a perturbation or abnormality in the sufferer’s immune system. This immunological malfunction, it is argued, may be triggered by a viral infection which somehow throws the immune system out of kilter.

Evidence that CFS involves an immunological disorder is accumulating rapidly. Within the past few years various abnormalities have been found in the immune systems of CFS sufferers. These include alterations in the activity and surface structure of two important types of white blood cells: the natural killer cells and T-lymphocytes. (You will be hearing much more about these cells in later chapters.) It is becoming increasingly evident that CFS is associated with, if not directly caused by, a persistent, low-level activation of the immune system.

If CFS really is an immunological disorder then why do some perfectly sensible scientists and physicians persist in regarding it as primarily a psychological disorder? They persist because there is highly respectable evidence to support their viewpoint as well.

Several of the symptoms associated with CFS are also seen in psychiatric illnesses, notably depressive and anxiety disorders. A substantial proportion of those who seek medical help for chronic fatigue turn out to have a recognizable psychological problem. The authoritative Centers For Disease Control and Prevention in the USA has concluded that approximately 45 per cent of all CFS sufferers have some form of identifiable psychiatric disorder before the onset of CFS. Researchers at the University of Connecticut School of Medicine found that as many as three out of four of the chronic fatigue cases they examined could be more easily explained by psychiatric problems such as depression. To add to the picture that the mind plays a central role in the illness, Australian researchers have discovered that CFS patients exhibit significantly more signs of hypochondria than other medical patients.

Psychological theories of CFS have tended to focus on depression. Over half of all CFS sufferers exhibit clear signs of clinical depression. Often the depression appears to have preceded the chronic fatigue, suggesting that it might be a cause rather than a consequence of the syndrome. Severe depression is usually accompanied by prolonged reductions in physical activity which could, in turn, lead to a debilitating decline in muscle function. People who lie in bed for long periods become physically weak. The sleep disturbances that typify some depressive disorders might also exacerbate the sufferer’s fatigue. Furthermore, it is known that severe depressive disorders are associated with changes in the immune system.

But hold fast. It is equally clear that many CFS sufferers become depressed as a consequence of their illness. It is hardly surprising that those suffering from a debilitating but unexplained illness should become depressed and abnormally preoccupied with their health. Although more women than men suffer from CFS this should not be interpreted as evidence that CFS is primarily a psychological disorder, as a few sexist pundits have implied. There are several perfectly respectable organic diseases, such as rheumatoid arthritis, which show a marked preference for one sex over the other.

At present it is probably safe to conclude that the case for CFS being primarily a psychological disorder remains unproven. The evidence for some sort of immunological malfunction is too good to dismiss. There is, however, no doubt that CFS sufferers’ psychological reactions to their illness do have an important bearing on their wellbeing and recovery. Whether depression is a cause or an effect of the syndrome, it becomes a major problem in its own right and can seriously impede recovery.

The controversy over CFS is further complicated by the attitudes of those who suffer from it. People who are afflicted by a serious and debilitating disorder such as CFS want their illness to be publicly recognized as having a medically respectable cause. For most people this means a physical cause, such as a virus or an immunological disorder, rather than a psychological cause. Any suggestion that their symptoms might result from a psychiatric problem tends to provoke outrage.

This attitude is understandable. Talk of psychological causes often carries with it an unjustifiable connotation that the illness is not quite genuine. There is usually a strong whiff of ‘get a grip on yourself and snap out of it’ in the air. Moreover, even in the late twentieth century there is still a wholly unreasonable stigma attached to mental illness. The average person would rather admit to having a physical illness, albeit a vague ‘mystery’ virus or obscure immunological malfunction, for this absolves them of any accusations of malingering, neuroticism or weakness of character. One unfortunate outcome of this desire for a physical explanation is the tendency, in some countries at least, for CFS sufferers to shop around until they find a physician who will give them the diagnosis they want.

Ironically, it turns out that the CFS sufferers who believe most strongly in a purely physical explanation have greater difficulty in recovering from their illness. This may be because they fail to confront and deal with the psychological problems that invariably accompany the illness.

Evidence to support this conclusion has come from a study conducted by Michael Sharpe and colleagues in Oxford. They found that a form of cognitive behavioural therapy, in which CFS sufferers were helped to re-evaluate their attitudes towards their illness, was of major benefit. More than 70 per cent of CFS sufferers who received the behavioural therapy regained their ability to function normally, compared with a success rate of 27 per cent for sufferers who received only standard medical care.

The pressure to attribute CFS to purely physical causes has also had a substantial influence on how the popular media deal with the subject. Newspaper and magazine articles, TV features and self-help books tend to emphasize physical explanations for CFS and neglect its psychological aspects.

A survey by researchers at the University of London found that 69 per cent of all articles on CFS which had appeared in national newspapers and women’s magazines since 1980 had favoured physical causes, compared to a mere 31 per cent of research papers in scientific and medical journals. There appeared to be a systematic bias in the popular media towards reporting physical as opposed to psychological explanations. Even the choice of name was affected. Whereas scientific papers typically used the neutral term chronic fatigue syndrome, the popular media instead favoured the more medical-sounding myalgic encephalomyelitis (ME).

Similar attitudes apply to other illnesses which, like CFS, have been tarred with the psychosomatic brush. Asthma and allergies are familiar examples. So too are inflammatory bowel disorders such as Crohn’s disease and ulcerative colitis. The pendulum of opinion has swung violently back and forth over the years. Half a century ago asthma was widely regarded as an essentially psychological illness. Nowadays it is normal to play down the role of psychological and emotional factors and instead focus almost exclusively on its immunological mechanisms and physical triggers, ranging from fitted carpets to car exhaust fumes. In truth, there are good grounds for believing that both immunological and psychological factors play important roles in these diseases. Nevertheless, the overwhelming tendency is to opt for one explanation to the exclusion of the other.

As we shall see in subsequent chapters, this centuries-old opposition between mind and body, mental and physical, psychosomatic and organic, is a snare and a delusion. It has impeded scientific understanding and acceptance of some very important phenomena. There is nothing ‘alternative’ or scientifically dubious about the fact that what goes on inside someone’s brain influences their physical health.