The Sickening Mind: Brain, Behaviour, Immunity and Disease

Ancient Greek medicine placed great emphasis on the curative power of katharsis – the purging and purification of the patient’s soul. Plato and other great thinkers recognized that these psychological charms were remarkably effective in relieving physical ailments. They also recognized that these charms would not work properly unless both the patient and the physician believed in their curative powers.

Nowadays the supposedly damaging effects on health of anxiety, over-work, job insecurity and loneliness form a recurrent theme in the media, which preaches the message that stress makes us ill. The implicit connection between mental state and physical health seems to be uncritically accepted by an increasingly health-conscious public.

There has been an explosive growth in alternative and complementary forms of medicine, which tend to emphasize the underlying unity of mind and body. Around one third of the adult population has consulted a practitioner of the alternative medical arts at some time. Bookshop shelves groan under the weight of publications proclaiming the self-help gospel that health is all a matter of thinking the right thoughts and banishing negative emotions.

The self-help industry and New Age gurus offer us such tantalizing prospects as self-healing through love, thinking ourselves better from cancer, using the mind to heal all manner of dread diseases and, ultimately, reaching that holistic nirvana of health, happiness and self-fulfilment through the power of pure thought. It is easy to see why the sceptical Roundheads can be so dismissive of the mind – body Cavaliers.

A profound change in the pattern of diseases during the twentieth century may also have contributed to this trend. The infectious diseases that killed vast numbers until fifty years ago have almost disappeared from the wealthy industrialized nations – though not from poorer parts of the world. Their place in the league table has been taken by chronic degenerative disorders such as coronary heart disease and cancer. Diseases of the heart and circulatory system, cancer and accidental injuries now account for more than three-quarters of all deaths. In contrast, infectious and parasitic diseases account for less than 0.5 per cent of all deaths.2

The causal factors that contribute to these modern-day killers are much more complex than the relatively understandable causes of infectious diseases. We all recognize that tuberculosis is caused by bacteria, but cancer and heart disease are altogether more obscure. It is therefore easier to believe that the mind may play a role in their genesis. Factors as diverse as tobacco, red meat, slothfulness, insufficient fibre, childlessness, salt, pesticides, sunburn and radiation can cause serious diseases, so why not psychological stress or depression?

But is there any scientific basis for these beliefs? Just because people have always assumed something to be true does not make it so. After all, the earth was at one time assumed to be flat, stationary and at the centre of the universe. This belief appeared to be supported by everyday experience and was universally accepted as a self-evident truth. Yet it turned out to be completely wrong. Folklore, faith and dogma are not always reliable guides.

In stark contrast to the popular attitudes we have the inherent scepticism harboured by many scientists and doctors towards the notion that mere thoughts or emotions could possibly have an impact on such brutally physical processes as viral infections, coronary heart disease or cancer.

Scientific research in this field has often been tinged with a largely undeserved aura of crankiness. ‘Psychosomatic’ phenomena carry with them a whiff of self-indulgent fantasy, along with the implication that they lack both substance and scientific respectability. The suggestion that psychological and emotional factors play a causal role in disease is often regarded as an admission that the real (i.e., physical) origins of the disease are not yet understood. As Susan Sontag put it in her 1978 book Illness as Metaphor: ‘Theories that diseases are caused by mental states and can be cured by will power are always an index of how much is not understood about the physical terrain of a disease.’

The belief in an intimate connection between mental state and physical health has had a decidedly rocky history in Western medicine, despite its promising beginnings in the civilizations of China and Greece more than two thousand years ago. By the end of the nineteenth century the overwhelmingly predominant approach to medicine was to focus exclusively on the disease and its identifiable physical causes, such as bacteria. Medical research could get to grips with bacteria, but thoughts and emotions were altogether too ethereal. The patient’s mental state increasingly came to be seen as an embarrassing irrelevance – the province of psychologists and other faintly disreputable types rather than a proper concern of scientific medicine. In later chapters we shall consider why the mind and body came to be separated in Western thought, and how this estrangement of psyche from soma has had such an all-pervasive influence on modern science and medicine.

Yet even in the late nineteenth century there were notable exceptions to this rule. For instance, in 1884 Daniel Hack Tuke, one of the pioneers of British psychiatry, published the second edition of a work entitled Illustrations of the Influence of the Mind Upon the Body in Health and Disease, Designed to Elucidate the Action of the Imagination. In it, Tuke argued that the mind and body are inextricably linked through physiological processes; and that our mental state consequently affects our physical health and vice versa. State-of-the art research in the closing years of the twentieth century has come to much the same conclusion – and not before time.

History shows that important ideas can be ignored even if there is good evidence to support them. It is worth recalling the uncomfortable fact that compelling scientific evidence for the connection between smoking, disease and death was available for many years before it started to be taken seriously. Nowadays the link between smoking and all manner of dread diseases is almost universally accepted. Yet this was not always so. Scientists had suspected that smoking was bad for health long before the first solid evidence for a connection with lung cancer was published in 1950. During the 1950s and 1960s a succession of studies concluded that smoking increases the risks of lung cancer, heart disease and a host of other life-threatening conditions. Nevertheless, governments, the general public and even doctors remained sceptical of these links, and two decades passed before the research started to have an impact.

Contemporary physicians and scientists frequently dismiss the idea that the mind has a profound effect on physical health. To quote an editorial from a prestigious international medical journal: ‘we have been too ready to accept the venerable belief that mental state is an important factor in the cause and cure of disease.’ Another sceptic, also writing in a leading medical publication, comments that ‘Mental stress is frequently blamed for the generation of organic disease, especially if it is of uncertain or complex aetiology, though without reliable or confirmatory argument … The morbidity of mental stress is commonly widely exaggerated.’ Or consider this trenchant counterblast from a third scientific sceptic:

During the last quarter of the 19th century many medical men asserted confidently that the stress of ‘modern’ life (i.e., all that gadding about in hansom cabs, paddle steamers, and railway trains) caused general paralysis of the insane [the final stages of syphilis]. Most of us now accept that this view was mistaken. I think that the notion that emotional factors have an important bearing on immunity, or on the cause or progress of cancer, comes into the same category.

In many respects the scientific evidence for connections between psychological factors and disease is stronger and more consistent than the evidence for certain other medical risk factors which are, nonetheless, regarded as less controversial. The putative links between dietary salt or cholesterol and heart disease are viewed with nothing like the same degree of suspicion and scepticism as psychological risk factors. Yet the scientific evidence that excessive salt or cholesterol in the diet actually cause heart disease in normal people is by no means conclusive. On the other hand, the evidence that psychological factors contribute to heart disease is wide-ranging and convincing, as we shall see later. There is a curious double standard at work here.

The fact is that most people, doctors and scientists included, find it inherently easier to believe in the reality of apparently simple physical causes of disease (such as cholesterol, salt, bacteria or viruses) than to accept that mere thoughts or emotions can affect our health. Partly as a result of such sceptical attitudes, research into the connections between the brain, behaviour, immunity and disease has, until recently, been remarkably neglected by mainstream medicine and seldom explained properly to the general public.

Can the starkly contrasting views of the uncritical Cavaliers and the sceptical Roundheads be reconciled? What are we to think when faced with conflicting claims about the mind’s role in disease?

As we shall see, the scientific truth is subtler than either of these two extreme views. It is also far richer and more exciting. It turns out that the folklore was in certain respects right, while the sceptics were wrong in their sniffily dismissive attitude. Research has uncovered an array of solid, compelling evidence that the mind does indeed play a part in a multitude of disease processes, ranging from commonplace bacterial and viral infections to heart disease and even cancer.

Some completely fictitious case histories

Before delving into the science, let us turn our attention temporarily to storytelling. If it is true that our mental state influences our physical health then this fundamental aspect of human nature ought to have been noticed and reflected in literature throughout the ages. What can we see in the mirror that fiction holds up to the human condition?

The links between the mind, emotions, behaviour, disease and death have indeed been reflected in the lives of fictional characters over the centuries. The writers describing these mind – body phenomena obviously had no conception of their biological basis, but that did not stop them noticing and portraying the connections. Throughout this book I shall be referring to literary illustrations of the links between psychological factors and disease. But first, let me spell out what these fictional case histories are intended to convey and, perhaps more importantly, what they are not intended to convey.

I shall use literary allusions because they help to convey complex scientific ideas in a recognizable form. Well-turned examples drawn from literature are more cogent and more entertaining than any medical case history, no matter how supposedly authentic it may be. They also demonstrate the antiquity and universality of many of the concepts that underlie current theories. However, by citing fictional characters or situations to illustrate scientific theories I am certainly not implying that they constitute hard evidence in support of those theories. Fine words drawn from the imaginations of long-dead authors are clearly not the same as scientific data.

The idea that physical decline can stem directly from mental and emotional decline is a familiar theme in literature. Fictional characters often die from unrequited love, grief, shame or fury. Emily Brontë’s Wuthering Heights, for example, is positively bulging with characters whose mental states lay waste their physical health. Death and disease run riot throughout the book. Let me remind you.

Believing his childhood sweetheart Catherine has spurned him, the tempestuous Heathcliff vanishes. Catherine, who does in fact love Heathcliff, is deeply upset and ridden with guilt. She consequently becomes mentally unstable and physically ill. Three years later Heathcliff returns. Catherine is torn between her love for Heathcliff and her love for Edgar Linton, whom she has meanwhile married. She breaks down under the mental pressure, shuts herself in her room and sinks into delirium. The vengeful Heathcliff subjects Catherine to an emotional battering which further weakens her health and she dies giving birth, a victim of psychological torment.

The bereaved Heathcliff determines to achieve his longed-for union with Catherine through his own death. He locks himself in a darkened room and wills himself to die. Four days later a servant enters the room to find his body. Heathcliff’s mind has killed him, as surely as if he had been shot:

Kenneth was perplexed to pronounce of what disorder the master had died. I concealed the fact of his having swallowed nothing for four days, fearing it might lead to trouble, and then, I am persuaded he did not abstain on purpose; it was the consequence of his strange illness, not the cause.

Death by shame is the tragic fate awaiting Madame de Tourvel in Choderlos de Laclos’s Les Liaisons Dangereuses, that tale of sexual intrigue among the enormously rich, enormously idle and enormously depraved aristocrats of pre-Revolutionary eighteenth-century France.

The young, pious and austere Madame de Tourvel is a devoted wife. Nevertheless, she is ruthlessly seduced by a satanic libertine, the Vicomte de Valmont – a man who ‘has spent his life bringing trouble, dishonour, and scandal into innocent families’. Valmont is egged on by the Marquise de Merteuil, his equally amoral former lover. Together they plot their seductions with the cold, unemotional precision of a military campaign.

Facing stiff resistance from the virtuous Madame de Tourvel, Valmont eventually breaks down her defences by convincing her that he will die from emotional torment unless she surrenders herself to him. Unable to resist his wiles any longer, Madame de Tourvel succumbs and Valmont has his wicked way with her.

The awful truth is then revealed – Valmont has cruelly deceived Madame de Tourvel and does not love her at all. In a fit of anguish and shame she flees to a convent, locks herself away and announces that she will not leave until she is dead. Her health rapidly deteriorates:

A burning fever, violent and almost continual delirium, an unquenchable thirst … The doctors say they are as yet unable to diagnose … As long as she is so deeply affected, I have scarcely any hope. The body is not easily restored to health when the spirit is so disturbed.

The wretched Madame de Tourvel dies, destroyed by her grief and shame. No physical agent, other than Valmont, has intervened.

Fate, however, wreaks its just revenge on the perfidious Vicomte de Valmont and Madame de Merteuil. Valmont is fatally injured in a duel. Soon afterwards, the correspondence of Valmont and Merteuil, detailing their devilish seductions, is revealed and becomes the topic of widespread gossip. Madame de Merteuil is publicly humiliated, and one day later is afflicted by a virulent attack of smallpox which leaves her horribly disfigured and blind in one eye.

Another victim of physical decline brought on by seduction and shame is the eponymous heroine of Samuel Richardson’s eighteenth-century blockbuster Clarissa. (At over a million words, it is also the longest novel in the English language.) Clarissa, a young lady of refined sensibilities, is seduced and raped by a superficially charming but unscrupulous bounder. Naturally – for this is eighteenth-century England – the dishonoured Clarissa is rejected and ostracized by her family and society. As her mental state declines, so does her physical health. Clarissa retreats into solitude and dies from grief and shame. Once again, a character’s psychological and emotional state has been the prime cause of her death.

There are of course innumerable other examples, all making similar points about the impact of emotions on health.3 We shall encounter a number of these in later chapters, and I hope it will be apparent that the notions they portray do bear some relationship to the reality revealed by modern science. However, at the risk of repeating myself, let me repeat myself: the fantasies of novelists are not the same as hard scientific evidence. Fortunately, there is plenty of that as well.

Invisible worms

O Rose, thou art sick.

The invisible worm

That flies in the night

In the howling storm,

Has found out thy bed

Of crimson joy,

And his dark secret love

Does thy life destroy.

William Blake, ‘The Sick Rose’,

Songs of Experience (1794)

The sharp divide between those who proffer psychological explanations for diseases and those who reject such theories in favour of purely physical causes is reflected in attitudes towards two particular disorders: tuberculosis and chronic fatigue syndrome.

Sir Peter Medawar, the Nobel Prize-winning immunologist and virtuoso science writer, once described tuberculosis as ‘an affliction in which a psychosomatic element is admitted even by those who contemptuously dismiss it in the context of any other ailment.’ There is abundant evidence, dating back hundreds of years, that the course and progression of tuberculosis are influenced by the sufferer’s mental state. The physical health of tuberculosis sufferers shows a tendency to deteriorate when they are subjected to severe stress or emotional upsets.

Someone who is infected with Mycobacterium tuberculosis, the bacterium that causes tuberculosis, develops a protective immune response which can hold the bacteria in check and prevent them from multiplying. The resulting stalemate between body and bacteria can mean that the disease will remain dormant for years. But if something happens to compromise or weaken the body’s immune defences, the bacteria can run riot and cause a resurgence of disease.

The importance of psychological factors in tuberculosis was widely acknowledged until well into this century. As early as 1500 BC, Hindu scripts described a wasting disease – almost certainly tuberculosis – of which one of the main causes was said to be sadness. Hippocrates, Galen and other medical luminaries of ancient Greece taught that grief, anger and other strong emotions played a major role in tuberculosis.

Throughout the seventeenth, eighteenth and nineteenth centuries many eminent European physicians stated that the causes of tuberculosis (or phthisis, as it was then known) included mental states such as ‘a long and grievous passion of the mind’, ‘a mournful disposition of the soul’, ‘ungratified desires’, ‘profound melancholy passions’ or ‘disappointment in love’. During the eighteenth and nineteenth centuries, students of tuberculosis refined the theory of a link between the disease and a specific set of psychological characteristics. This was formalized in the concept of the tuberculosis-prone personality, or spes phthisica. As we shall see later, modern science has revived the concept of disease-prone personality types with the discovery of certain intriguing associations between personality traits, heart disease and cancer.

More familiarly, we have the romantic nineteenth-century notion that consumption (as tuberculosis was then known) is caused – or, more accurately, exacerbated – by an artistic temperament. Consumptive artists or writers were believed to be consumptive primarily because of their excessive artistic and aesthetic emotions, which literally consumed them. Consumption came to be something of a status symbol among the chattering classes.

Countless noted writers, artists and musicians of the nineteenth and early twentieth centuries did indeed suffer from consumption. Emily Brontë is but one example. She died of tuberculosis, a bitterly disappointed woman, within a year of Wuthering Heights being published to withering reviews. Other creative victims of tuberculosis included John Keats, Frédéric Chopin, Robert Louis Stevenson, Stephen Crane, Katherine Mansfield, Robert Tressell, D. H. Lawrence, George Orwell and Franz Kafka. It is said that Kafka’s health was weakened by his chronic unhappiness, his hypersensitive personality, his problematic relationship with his father and several unfortunate romantic tangles. He died in an Austrian sanatorium in 1924, aged forty-one.

On the other hand, tuberculosis accounted for more than one in five of all deaths in the nineteenth century and was still common in Europe until well into this century. On statistical grounds it is hardly surprising that at least some prominent names were included among its victims.

The fiction of the eighteenth and nineteenth centuries reflects this preoccupation with tuberculosis and the prevailing attitudes towards it. We can choose from a panoply of heroes and heroines who sink into tubercular decline in the aftermath of romantic tragedy. We have, for example, the ever popular tale of La Dame aux Camélias, Alexandre Dumas the younger’s tear-jerker about the passionate but doomed love affair between Armand Duval and the enchanting courtesan Marguerite Gautier.

The young Duval meets Marguerite and is captivated by her. They become lovers. Marguerite is already consumptive, but under the healing influence of Armand’s love she abandons her dissolute lifestyle and her health improves. Meanwhile, Armand’s well-meaning father secretly persuades Marguerite that if she truly loves Armand she will leave him for his own good. Marguerite demonstrates her love for Armand by doing just that.

The cynical Armand thinks Marguerite has abandoned him out of boredom so that she can resume her former life of late nights, promiscuity and wild self-indulgence. He therefore sets out to punish her by humiliating her at every opportunity and revelling in the spectacle of her suffering:

… for the last three weeks or so, I had not missed an opportunity to hurt Marguerite. It was making her ill … Marguerite had sent to ask for mercy, informing me that she no longer had either the emotional nor physical strength to endure what I was doing to her.

As a consequence of her deep unhappiness at their separation and the psychological battering she receives from Armand, the much-wronged Marguerite goes into terminal decline. Her consumption flares up and she expires. Armand realizes his error, but not until too late.4 As the narrator sagely concludes: ‘I have learned that one such woman, once in her life, experienced deep love, that she suffered for it and that she died of it.’ Though Marguerite dies from tuberculosis, it is her emotions that have killed her. La Dame aux Camélias was, incidentally, modelled on Dumas’ personal experience following his affair with the courtesan Marie Duplessis. Like the fictional Marguerite, Marie died of consumption not long after the affair ended.5

Until the early part of the twentieth century, popular medical literature was largely in tune with fiction in the way it emphasized the importance of psychological and emotional factors in tuberculosis. To quote one everyman’s guide to medicine from the 1930s:

Happiness is a mighty important factor in the treatment of tuberculosis … Mental brooding and loss of hope of recovery or of checking tuberculosis tends to drag the unfortunate individual into a deep chasm from which escape is rare.

So, what happened and why have attitudes changed?

What happened was that in 1882 the German scientist Robert Koch announced to the world that he had discovered the real cause of tuberculosis – the tubercle bacillus, Mycobacterium tuberculosis. Once it became known that tuberculosis was a bacterial infection, scientific interest in the role of psychological and emotional factors rapidly dwindled. The pendulum swung violently from the psychological to the physical. Open a contemporary medical text on tuberculosis and the chances are you will find little mention of psychology, emotions or the mind.