INTRODUCTION AND OVERVIEW

The father of Western medicine, Hippocrates, said that ‘the human being can only be understood as a whole’. Such sentiments are reflected in many cultures. Generally speaking, ancient approaches to health are essentially holistic, with wellbeing, illness and healing considered to be strongly connected to the mind, society, morality, spirituality and ecology. In this view, nature is imbued with intelligence, consciousness and order, and it is the role of the healer to observe, understand and follow these laws. Furthermore, any understanding of the universe or the creatures existing within it is metaphysical in nature—that is, mind or intelligence governs physical phenomena.

To the ancient Greeks, as with other ancient Eastern and Western healing systems, the ‘whole person’ encompasses the body, the mind—including thought and emotion—and the spirit or consciousness. The physical body, viewed as the most superficial aspect, is ‘moved’ or enlivened by the deeper aspects of the ‘self’. It is analogous to the driver of a car being the mind and the car being the body. Consciousness is the primary substance of our being and also the source of energy. The mind gives form and direction to consciousness. Thus, what affects one level of our being also affects all the others. This interrelationship as defined by ancient healing systems is echoed in the WHO holistic definition of health as:

In the nineteenth and twentieth centuries, with the rise of a more reductionist and materialist approach to science, this ancient and holistic view has been supplanted. As a consequence, explanations for phenomena have become far more mechanistic in nature. Human development can be explained by genes, thought and emotion by neurotransmitters, and even love by evolutionary biology.

More recently, however, this mechanistic and materialistic view of science has again been questioned, not so much from initiatives started by religious institutions, but from within the scientific establishment itself. Much of this is due to collaborative research between psychologists, sociologists, immunologists, physiologists and neuroscientists. The broad term given to these new scientific disciplines is ‘mind–body medicine’ (MBM). Essentially, although we now have a complex understanding of the mechanisms underpinning the mind–body interaction, it is clear that the principles were well understood in ancient times. These principles are extremely simple and, as such, they have enormous application to modern clinical practice although, of course, this integration needs to take place alongside sound clinical practice and the best available evidence.

WHAT IS MIND–BODY MEDICINE?

The main premise of MBM is that the mind (intelligence) governs or regulates the body. Although mind is non-physical—and therefore MBM is in essence a metaphysical explanation for physical phenomena—mind uses the body to execute its purposes. More particularly, the mind, powered by consciousness, thinks and feels through the agency of the brain. Mind, brain and body are inseparable. Mind and intelligence make themselves evident by observable results in the physical world.

A practical way of expressing this principle is to say that psychological states such as chronic stress, depression, anxiety and fear produce profound and clinically relevant effects upon the body. These effects have implications for health and illness. Psychological states and social context can have both positive and negative effects that manifest on many different levels, all the way from muscle tension to genetic expression. Over time the cumulative effects of negative mental and emotional states can take a heavy toll on the body. Conversely, research also suggests that psychosocial interventions can play an important part in ameliorating these negative effects and can assist in promoting healing.

Despite the enormous scope and clinical potential of MBM, it has been relatively slow to enter mainstream medical education and practice. This lack of awareness among clinicians tends not to be reflected in the general community, which has a strong interest in and intuitive appreciation of MBM principles, although expectations are sometimes unrealistic. The desire for a ‘holistic philosophy’ to underpin healthcare is a major reason that many people search out complementary therapies.²

The relative slowness of the medical community to integrate MBM may be the result of a number of things, including a lack of access to current research findings, bias against explanations that do not fit assumed scientific paradigms, and lack of economic interest in non-patentable and non-technological therapies. This will no doubt change as medical practice evolves to encompass changing community values, the growing evidence base behind MBM, and the need for more cost-effective and less invasive approaches to therapy.

This chapter provides a broad overview of the medical literature on MBM and explores some of its clinical implications. Subsequent chapters on various systems also include content on MBM where relevant. Without paying attention to the mind, we may be dealing only with the manifestations of diseases, not their causes.

Acknowledging the role of the mind’s effect on the body does not deny the important role of physical risk factors and treatments. Indeed, the approach recommended in this textbook is to use the best that conventional medicine has to offer, but within a holistic context. Recognising, for example, that stress and emotion can exacerbate asthma does not ignore the importance of pharmacological therapy, careful monitoring and occasional emergency care.

THE CAUSE AND EFFECTS OF STRESS

It is best not to take the label ‘stress’ at face value without exploring what a person means by it. ‘Stress’ is a commonly used term covering, often imprecisely, a wide range of human experiences. Some describe stress as a ‘perceived inability to cope’, others as when ‘demands exceed means’. Patients may use the word ‘stress’ in these contexts, but often it is used to describe psychological and emotional states such as fear, anger, indecisiveness, distractibility, depression or rumination. Stress can also be used by many to describe the physical effects of increased sympathetic nervous system (SNS) activity such as increased muscle tension, tremulousness, clamminess or rapid heartbeat. These manifestations of the ‘fight-or-flight response’ can lead to tiredness and other symptoms associated with chronic stress.

Most affluent countries around the world are observing significant increases in the rates of stress, depression and suicide. Evidence suggests that stress hormones play an important role in the development of psychiatric disorders³ as well as having direct effects on serotonergic pathways.⁴ Serotonin is the principal neurotransmitter implicated in depression, and antidepressant medications are largely aimed at modulating serotonin.

Chronic stress and the accumulation of a number of minor stresses is a contributor to many illnesses. When appropriately activated, the fight-or-flight response is a natural, necessary and life-preserving physiological response to a threatening situation. For example, if you are about to be chased by a lion, you need to:

The fight-or-flight response, when based on a clearly perceived and real threat, is physiologically encoded to preserve life, and therefore the changes associated with it make sense. These changes include:

These changes, designed to help the body cope with demands and potential injury, will mobilise according to whatever we perceive as a threat. When the situation is over, the physiology should return to rest if the situation is mentally left in the past. Even one’s own doctor can be perceived as a threat. The prospect of having one’s blood pressure measured is enough to elevate it to a point where approximately 25% of patients are inappropriately diagnosed with hypertension.⁵ This is known as ‘white-coat hypertension’ and is just another example of the clinical implications of the mind–body response.

The activation of the fight-or-flight response is not detrimental to health, provided it is mobilised only when it needs to be, is deactivated when it is no longer required, and is not prolonged. Unfortunately, in the vast majority of occasions on which this response is mobilised, it is done so unnecessarily and is maintained long after the event is passed, and the person is unable to deactivate it. Much of the inappropriate activation of the response has to do with the imagination of future and past events taken to be real. The word ‘anxiety’ comes from a Latin word, anxius, meaning to ‘anticipate some future event’. Furthermore, mentally replaying an event can reproduce the stress response many times even though the event is over and happened only once. In the most extreme cases this replaying can be so vivid that a person’s present experience is all but totally overlaid with the past, leading to what is called ‘post-traumatic stress disorder’. Here, through neuron plasticity, the memory, emotion and physiological response have become wired into the neural circuitry of the brain, principally through the limbic system, which mediates memory and emotion.

The chronic or long-term inappropriate activation of the stress response, mediated through the SNS, leads to a significant level of physiological wear and tear. This is called ‘allostatic load’.⁶ It is much like a car being driven so hard that the heavy demands placed upon it will lead to failure of its parts. High allostatic load is associated with both anxiety and depression and will lead to, among other things:

These effects are logical sequelae of the prolonged activation of the SNS. Stress and inflammatory mediators, such as cytokines, also have important effects on mood, behaviour and emotion.⁷ Activation of the immune system via these immune mediators, such as takes place during an acute infection, induces sickness behaviour (apathy, lethargy, lack of motivation and appetite). This behaviour is the body’s way of ensuring that one takes the rest required to assist the body in recovering from an infection. Many of these symptoms are also seen in depression and a significant part of the reason may be because of the high levels of cytokines associated with high allostatic load. Some cytokines activate cerebral noradrenergic and serotonergic systems and so anxiety and depression are often seen as a mixed picture. It may also be part of the reason that depression occurs more frequently in people with medical disorders associated with immune dysfunction. From a therapeutic perspective it is important to remember that every investment in reducing anxiety, improving coping and enhancing wellbeing is a step towards reducing suicide risk.

MENTAL HEALTH INDICATORS

Measures of mental health in developed countries have not been heading in a positive direction in recent decades:

Evidence suggests that the stress associated with modern life has been increasing at a surprisingly rapid rate: 45% over the past 30 years in some surveys.⁹ Depression currently ‘causes the largest amount of non-fatal burden, accounting for almost 12% of all total years lived with disability worldwide’¹⁰ and it is estimated that in Australia mental health issues, principally depression, will be the major cause of morbidity within the next two decades.¹¹ Among affluent countries around the world it is estimated that, by the year 2030, unipolar depression will account for over 1.5 times the burden of disease that will be accounted for by cardiovascular disease.¹² This is independent of the secondary effects of depression, such as it being an independent risk factor for heart disease and associated co-morbidities such as substance abuse.

The higher prevalence of poor mental health could be explained in part by an increased awareness of mental health issues. Aside from this it is apparent that many people have more pressured and stressful lives. The rapid increase in the amount of social change, job insecurity, the speed of life, escalating competitiveness, higher expectations and many other factors all contribute.

Today, higher rates of depression are occurring at younger ages. Suicidal ideation is surprisingly common in adolescents. Data suggest that 1 in 2 young people report experiencing high levels of psychological stress and as many as 25% of 15–24 year-olds presenting to a GP for any reason reported experiencing recent suicidal thoughts¹³ despite the fact that most did not present for psychological reasons.

Evidence suggests that antidepressant medications in children and adolescents, although widely used, are not effective and that such approaches have to be questioned.^14,15 Part of their overuse may be driven by marketing forces and parental anxiety. Particularly in this group of patients it is important for attention to be paid to the social and domestic causes of stress and to the fostering of protective factors and resilience through education and community programs.

The causes of declining adolescent mental health are contributed to by a wide range of factors, including physical inactivity, poor nutrition, substance abuse and social influences. Some elements of youth culture and excessive pleasure-seeking behaviour may also be contributing factors. Although adolescents will ‘self-medicate’ for depression by using substances and promiscuous sexual behaviour, recent studies also suggest that substance abuse and promiscuous sexual behaviour precede and predict the later development of depression: ‘Engaging in sex and drug behaviors places adolescents, and especially girls, at risk for future depression.’^16a

Some groups on the fringe of society, such as the Goth subculture, seem to be at very high risk for self-harm and attempted suicide.¹⁷ Music is also a powerful modulator of emotion and behaviour and can significantly increase risk-taking behaviour.¹⁸ The assessment and management of mental health issues among adolescents therefore requires attention to such issues.

DOPAMINE AND REWARD SYSTEMS

Different brain pathways accord with differing approaches to pursuing fulfillment. Dopamine is a neurotransmitter with multiple actions at each level of the mesocorticolimbic reward pathway—it is intimately associated with the ability to experience pleasure and motivation.¹⁹ The pursuit of pleasure is a vital activity associated with survival. For example, we would not eat or reproduce unless it was pleasurable. Some people are, however, more genetically at risk of developing addictive behaviours, and the over-activation of the mesolimbic system can trigger addictions of various kinds. In such situations it requires increasingly intense and frequent stimuli to produce the same pleasure response; over time, this ‘tires’ the reward system, predisposing to anhedonia and depression. Dysfunction of dopamine transmission in the reward circuit is associated with symptoms such as anhedonia (inability to experience pleasure), apathy and dysphoria (disturbed mood). It is found in various neuropsychiatric disorders, including Parkinson’s disease, depression and drug addiction. Prolonged and significant stress early in life can also affect one’s dopamine pathways for life.²⁰ What begins as a pursuit of pleasure eventually becomes an uneasy retreat from the pain and anxiety associated with withdrawal. This has implications for the development of impulsivity and reactivity.

Increased dopamine release is also seen in the brain during the relaxation response. This is associated with reduced impulsivity or reactivity,²¹ which may have something to do with the development of emotional and impulse regulation associated with long-term meditation practice. This may also help to facilitate healthy lifestyle change.

Mood, neurochemistry and behaviour are intimately entwined. Mood affects behaviour and is a common reason for relapse into unhealthy behaviours.²² Major depression, for example, triples the risk of progression to daily smoking²³ but, conversely, a history of daily smoking nearly doubles the risk of major depression. In adolescents, experimental smoking very significantly increases the risk of taking up smoking as a habit. Depression, anxiety and peer smoking strongly predict the risk of experimental smoking, and depression and anxiety increase susceptibility to peer influence to establish risk-taking behaviours. Building resilience and emotional intelligence in adolescents, particularly boys, may therefore produce a number of benefits including the ability to avoid unhealthy behaviours. It also goes part of the way towards explaining why CBT and antidepressant medications both reduce relapse rates for smokers.^24,25

Brain scans show that mental anticipation can have as significant an effect upon brain activity as physical stimulation. The thought of eating activates areas of the brain associated with rewards and pleasure.²⁶ As these centres are important in addictions it is likely that potential forms of therapy for treating addictions will be developed that target these biochemical reactions pharmacologically²⁷ and behaviourally.

STRESS AND PERCEPTION

That stress is intimately related to perception is not a new concept. The mind has a key role in eliciting the stress response through its functions of perception, cognition, interpretation and conditioning. When perceptions are distorted or cognitions are irrational, this leads to a consequent inappropriate activation of the stress response.

Learned patterns of coping and personality styles are generally more influential than the situation in activating the stress response. By understanding the basic mechanisms that underlie this process, it is possible to use strategies to deactivate it. Such strategies can include:

These help to reverse the effects of inappropriate stress by attacking it at its cause—thought. Reviews of the literature suggest that cognitive and relaxation-based forms of stress management are the most effective strategies in general practice settings, and that working in groups potentiates outcomes.²⁹ A certain amount of stress can be useful in enhancing motivation. Furthermore, the fight-or-flight response can be entirely necessary in extreme situations. Aside from this, however, most of the stress experienced in daily life is neither necessary nor helpful in improving our ability to deal with a challenge. Most of the unhelpful stress experienced is associated with an agitated and unfocused mind that also has a limited capacity at the time to distinguish between present-time reality and imagination. Mental projections and anticipation are given a reality they do not deserve. Examples might include projecting fears into the future about upcoming exams or interviews or habitually recreating past anxieties and conflicts. Here the stressors are in the mind, not in reality, but the body will nevertheless faithfully translate this mentally generated stressor into the stress response. It will not stop until it is told to, regardless of whether the stressor is real or imagined. If one imagines a rope to be a snake, the body will react to the perception, not the reality. Even events that are actually happening at the time will only cause stress depending on the mental interpretation of them. To attribute our stress solely to the events around us and to ignore our own role in generating stress is disempowering and will lead to less than favourable therapeutic outcomes.

GENDER AND THE STRESS RESPONSE

Much of the early stress research focused on men, and hence the fight-or-flight response, which is largely a male response, has become the predominant paradigm in stress medicine. But there is good evidence to suggest that women do not respond to stressful situations in entirely the same way as men, emotionally, socially, behaviourally or physiologically. Reviews of the literature ‘suggest that the female stress response of tending to offspring and affiliating with a social group is facilitated by the process of “befriending”, which is the creation of networks of associations that provide resources and protection for the female and her offspring under conditions of stress’.³⁰

Both males and females have the capacity to activate the fight-or-flight response if required, but men are especially built for this response. Testosterone contributes significantly to this³¹ and also has a role in the development of ‘rough- and-tumble play’ and sporting interests among boys. Excessive testosterone levels are implicated in excessive physical aggression and crime among men. Female aggression, on the other hand, is more ‘cerebral’—that is, it seems more likely to be expressed ‘in the form of gossip, rumour-spreading and enlisting the cooperation of a third party in undermining an acquaintance’.³²

The females of most species are more involved in tending the young because they have the biological or behavioural disposition to ‘tend-and-befriend’. In humans this effect is largely mediated through female hormones such as oxytocin and oestrogen.³³ Levels of these hormones are highest during activities like breastfeeding as well as in social interaction, massage and caring physical contact. These hormones have a calming or settling effect on stress and down-regulate the fight-or-flight response.³⁴ Women therefore have less of a tendency to become overly aggressive. None of this suggests that men cannot tend and befriend, or that women cannot elicit the fight-or-flight response when required, but it does suggest that each gender is more or less adapted for one or other response. This is an example of the complementarity of nature but equally it is part of the reason that men and women will respond in different ways to life events and therapies. Women, for example, will tend to feel more comfortable with talking-based therapies, especially dealing with emotional content, whereas men will more often wish to approach problems in an action-based way.

STRESS AND PERFORMANCE

One of the reasons that many people value stress is that they use it as a motivator to enhance performance. It is an assumption for many that if there were no stress there would be no performance. Inertia is, initially at least, a low-stress state but as stress increases, perhaps before an exam or a deadline, stress will often stimulate an increase in performance (Fig 8.1). If the stress remains manageable and is not too prolonged, then there tends not to be a significant problem. If, however, the stress escalates due to rising demands on performance, and stress is the only motivator being used to drive performance, then the person goes over the top of the stress-performance curve (red line) and finds that, despite high stress and energy consumption, performance drops. If this situation goes on for long, burnout soon eventuates.

FIGURE 8.1 Stress–performance curve

There is another option (green line). We will have had experiences when we functioned at our peak. In athletic circles this is called ‘the zone’; it is also called a ‘flow state’. In such a state there is an increased focus of attention and this has two significant effects. First, because attention is less monopolised by anxieties and fears there is a reduction in stress, leading to a sense of being inwardly calm. Secondly, because of the high level of focus or ‘restful alertness’, the resulting perceptiveness is associated with a high level of performance and efficiency. A hallmark of this state is a sense of effortlessness.

Unfortunately, burnout is common, particularly among doctors. A study of medical interns found a steady increase in the point prevalence of burnout, which peaked at a prevalence of 75%, 8 months into the intern year. Seventy-three per cent of interns met the criteria for psychiatric morbidity—that is, an anxiety or depressive disorder—on at least one occasion throughout the year.³⁵ For this reason, an increasing number of medical schools are introducing self-care skills into medical education to foster resilience for later careers. Burnout is measured by levels of things such as depersonalisation, lack of motivation and low sense of achievement.

Even in the absence of burnout, living and working in a ‘hyperkinetic environment’ encourages a lower level of focus, which some call ‘attention deficit trait’ (ADT).³⁶ In dealing with so much input coming at such a speed, a person tends to become increasingly reactive, adopts ‘black-and-white thinking’, has difficulty staying organised and setting priorities, and manages time poorly. It is often associated with a constant low level of panic and guilt. The management of ADT is through learning to focus or regulate attention, lifestyle maintenance, changing the environment to be less frenetic and learning how to stop at the end of the day.

Studies of learning styles indicate that certain motivation and learning styles need stress to drive performance, and others don’t. Biggs’ model describes three learning approaches: surface learning, achievement learning and deep learning.³⁷ Deep learners are driven by interest, not stress, and do not need stress to perform well. They integrate what they learn and tend to enjoy it far more. Surface learners tend to learn by rote and the main motivation is to avoid failure. Achievement learners often study hard but are motivated by ego-enhancement, that is, wishing to achieve well in order to earn respect or look good. Surface and achievement learners tend to need stress to perform. The highest achievers all use deep approaches, while third-class honours students tend to use surface approaches.³⁸

MIND AND BRAIN

In the field of MBM, there is much debate about the distinction, if any, between mind and brain. Are they the same, or does the mind communicate through the brain? In this view, mind is non-physical and is constituted by thought and emotion. The brain, on the other hand, is the physical organ that translates thought and emotion into biological and electrical activity and thereby regulates the body. The statement that an illness, pain or stress is ‘in the mind’ is correct, but it is also in the body.

Depression is an emotional state that is also associated with a range of other symptoms and somatic effects. These are mediated via the neurotransmitter and hormonal changes associated with depression and the rich interconnections between emotional and cognitive centres in the brain. Although there are undoubtedly changes in neurotransmitter profiles in the brain associated with depression, serotonin being the most important, sophisticated brain-imaging techniques are making it clear that thought and belief have a major role in driving brain activity. Functional MRI (fMRI), for example, can show that changes in brain activity associated with the placebo response when a person receives a mock antidepressant is biologically similar to that in people who receive the active drug. Such observations are impossible to explain with the view that the cause of recovery from depression is purely a chemical one. The same is also seen in people who receive placebo analgesics by mapping regional metabolic changes in parts of the brain that modulate the pain response.^39,40 Interestingly, brain scans mapping the recovery from depression associated with cognitive approaches demonstrate that it is via different pathways than those associated with pharmacological therapies.^41,42

In various chronic pain syndromes, the changes in the brain associated with stress and sympathetic nervous system reactivity sensitise the pain pathways in the brain to register pain messages even with relatively low-level stimuli and in the absence of tissue damage. To the person experiencing the chronic pain syndrome, the experience of pain feels real. This is part of the reason that chronic pain and other manifestations of somatisation are such common accompaniments to emotional states such as depression, anxiety and burnout. It also explains, at least in part, why it is often difficult to demonstrate tissue damage associated with pain in various conditions such as chronic musculoskeletal pain, chronic low back pain, chronic fatigue syndrome and fibromyalgia.⁴³ Sustained attention and arousal are crucial in creating and sustaining the neural loops associated with chronic pain.⁴⁴ In other words, when a person becomes highly vigilant and reactive to pain messages, the brain will fire off pain messages with fewer and fewer stimuli. From a therapeutic perspective, this may be part of the reason that attention regulation exercises, such as mindfulness meditation, help in chronic pain syndromes. It is likely that the reduced reactivity to sensations may actually help to ‘rewire’ the brain in a way that minimises these effects.

Depression, stress and other psychological and emotional states are undoubtedly associated with physical sequelae. For instance, it has been shown that chronic severe depression is associated with a fivefold-increased risk of coronary heart disease independent of other risk factors.⁴⁵ These effects are not just the result of changes to one neurotransmitter—serotonin. There is a huge variety of biochemical, physiological and hormonal changes relevant to the cardiovascular system that are associated with depression. It therefore follows that treating depression with antidepressants does not significantly reduce the risk of cardiovascular disease. If, however, thought changes biology, then changing thought for the better among depressed patients should have a more significant effect in reducing the risk of cardiovascular disease, which it does. A meta-analysis of 23 studies clearly showed major reductions in ongoing morbidity and mortality for cardiac patients who received, as part of their rehabilitation, psychosocial interventions aimed at improving coping and emotional health.⁴⁶ The increased risk for those with no psychosocial treatment as a part of their ongoing management was 1.70 for mortality and 1.84 for recurrence. The conclusions drawn from this study were unambiguous: ‘The addition of psychosocial treatments to standard cardiac rehabilitation regimens reduces mortality and morbidity, psychological distress, and some biological risk factors … It is recommended to include routinely psychosocial treatment components in cardiac rehabilitation.’

The above discussion has given some indication of the scope and potential of MBM.

THE EFFECTS OF STRESS REDUCTION

Psychological stress affects every system of the body. For example, there are effects on cardiac risk factors such as:

Stress affects immune function (see section on psychoneuroimmunology, later in this chapter), slows wound healing^63,64 and alters genetic function, damage and repair (see section on genetic expression, later in this chapter). The implications are enormous.

The relaxation response, on the other hand, reverses the harmful effects of the inappropriate activation of the stress response. The ‘relaxation response’ was first coined by Professor Herbert Benson of Harvard University.⁶⁵ Although it can be fostered in a variety of ways, the effects are similar: a relaxed physical condition and a focused and alert mental state. This state of body and mind is sometimes called ‘restful alertness’.

Some of the physical and psychological effects of stress that can be reversed through stress reduction techniques are listed in Boxes 8.1 and 8.2.⁶⁶ Overall there is a restoration of physiological balance or homeostasis. This movement towards balance, efficiency and health is natural and will take place automatically if it is not interfered with. Similarly, the mind will return to happiness and contentment if it is allowed.