Do biomedical models of illness make for good healthcare systems?
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《英国医生杂志》
1 Oxford Centre for Enablement, Oxford OX3 7LD, 2 Cardiff University, Cardiff CF10 3YG
Correspondence to: D T Wade derick.wade@dsl.pipex.com
Current medical models assume that all illness is secondary to disease. Revision is needed to explain illnesses without disease and improve organisation of health care
Introduction
The model of illness adopted by society can have important consequences. In the first world war, for example, soldiers complaining of symptoms after experiencing severe stresses were sometimes shot as malingerers, but today they are considered victims and eligible for financial settlements Social acceptance that a behaviour or reported symptom constitutes an illness bestows privileges on an individual and formal duties on society.3
Currently, most models of illness assume a causal relation between disease and illness—the perceived condition of poor health felt by an individual. Cultural health beliefs and models of illness help determine the perceived importance of symptoms and the subsequent use of medical resources.4 The assumption that a specific disease underlies all illness has led to medicalisation of commonly experienced anomalous sensations and often disbelief of patients who present with illness without any demonstrable disease process.
Current models of illness
People often experience anomalous sensations.8 w9 The model of illness adopted will influence whether a person or their health adviser interprets a change in their state as indicating disease,9 when someone should enter and leave the sick role, and often the health care given. Only a small minority of potential symptoms lead to involvement with health care, but a small change in the rate of interpreting anomalous sensations as symptoms by any party will have a major influence on the use of healthcare systems.
Being ill, and being allowed to enter the sick role, has social and personal advantages for the person.3 Sick people may be absolved from social responsibilities, they are not held responsible for their condition, and they will often be eligible for healthcare benefits for which they do not pay directly. The sick role is most effective when it is validated by a doctor, but increasingly other health and non-healthcare professionals contribute to validation; indeed, ill people can now classify themselves as sick—for example, through self completed incapacity benefit forms in the United Kingdom.
Already many patients present with symptoms that are not attributable to any underlying pathology or disease.10 Nevertheless, such patients are often given a medical diagnosis, implying an underlying structural cause and reflecting cultural expectations.
Unfortunately, the use of diagnostic labels has implications for the patient, society, and ultimately for the credibility of medicine. Any illness provided with a (medically validated) diagnostic label is widely assumed to be secondary to defined pathology, to be capable of confirmation independently of the symptoms, and to have a specific treatment that health services should supply.
The problems arising from illnesses without a definable cause have been well documented.11 They are most appropriately termed functional somatic syndromes,12 w10 w11 recognising that psychological and social factors strongly influence the presentation of somatic symptoms.w12 However, suggesting that patients do not have a disease (pathology) to explain their illness may understandably upset them13 and creates difficulty for healthcare bureaucracy which relies on the patient's specific disease label.
Funding is determined by diagnosis (in health related groups or similar) and ignores the initial cost associated with diagnosis (patients present with problems, not diagnoses). It also fails to recognise that a major part of healthcare cost relates to disability.14 Resources are primarily allocated for the diagnosis and specific treatment of disease. Little attention is paid to other interventions despite good evidence of their effectiveness. Examples include the provision of equipment,w13 w14 the use of specialist multidisciplinary stroke rehabilitation units,w15 and the altering of patients' beliefs.w16 Most healthcare systems also assume that treatment after diagnosis is brief and acts quickly. Indeed, the medical model might more accurately be termed the surgical model, given the pre-eminence of surgery in popular culture and health organisation.
Finally, most biomedical models also seem strongly linked to primitive forms of intuitive mind-body dualism. Health commissioners, budgetary systems, healthcare professionals, and the public all act as if there is some clear, inescapable separation between physical and mental health problems, ignoring evidence that a person's emotional state always affects their function and presentation of physical symptoms.w17 w18 For example, separate services exist for people with physical disability and for those with mental health problems.
New model
This model has many implications (see table A on bmj.com). One characteristic of a systems model is that abnormalities in one system can occur without any of its components being faulty, and so the model explicitly predicts that illness will occur without discernable pathology. The mystery of non-organic or functional12 illness is no longer medically unexplained.17 This analysis does not deny the reality of the illness but rather provides the rationale and support for explanations and treatments that direct their focus to the non-medical reasons why people may feel ill.
This model also predicts that the effects of an abnormality may depend crucially on the characteristics of other parts of the system. For example, hip arthritis may become apparent only after a stroke affects the other leg. Consequently, reduction of illness may require intervention at several points, and indeed may not necessarily include removal of the main abnormality; this may explain the success of specialised stroke rehabilitation.w15
The model suggests that some resources should be focused on altering contextual factors. Evidence already supports this approach: teaching carers of stroke patients benefits both the patient and healthcare systemsw22 w23; changing social contextw24 may be effective—for example, reducing time off work with back painw25; altering personal context may help in some illnessesw26—for example, using cognitive behaviour therapyw16; and improving the physical context reduces expenditure on health care.w13
The role of personal choice, absent in many biomedical models of illness,18 is central to any progressive explanation of human behaviour: "People are rational, aware self creating agents of their own health... influenced by consciously chosen goals."19 Personal choice plays an important part in the genesis or maintenance of illness, particularly in and through the domain of activities.
This model also illuminates some of the current stresses within health care and illness related benefits systems. Systems focused on pathology (that is, hospitals) work in short time scales and ignore all patient context. However, they have to manage patients with activity limitations, in whom the time scale is longer and context is important. A coherent approach to rehabilitation inevitably requires action from other agencies such as social, housing, or employment services. When the characteristics (speed of priorities, available interventions) across organisational boundaries do not match each other or the needs of the patient, stresses may arise (often referred to as bed blocking in hospital).
Conclusion
Wade DT, Halligan P. New wine in old bottles: the WHO ICF as an explanatory model of human behaviour. Clin Rehabil 2003;18: 349-54.
World Health Organization. International classification of functioning, disability and health. WHO: Geneva, 2001.
Parsons T. The social system. Glencoe, IL: Free Press, 1951.
Kirmayer LJ, Young A, Robbins JM. Symptom attribution in cultural perspective. Can J Psychiatry 1994;39: 584-95.
Porter R. The greatest benefit to mankind. A medical history of humanity from antiquity to the present. London: HarperCollins, 1997.
Oliver M. Social work with disabled people. Basingstoke: Macmillan Press, 1983.
Engel GL. The need for a new medical model: a challenge for biomedicine. Science 1977;196: 129-36.
Turner J. Medically unexplained symptoms in secondary care. BMJ 2001;322: 745-6.
Smith R. In search of "non-disease." BMJ 2002;324: 883-5.
Carson AJ, Ringbauer B, Stone J, McKenzie L, Warlow C, Sharpe M. Do medically unexplained symptoms matter? A prospective cohort study of 300 new referrals to neurology outpatient clinics. J Neurol Neurosurg Psychiatry 2000;68: 207-10.
Malleson A. Whiplash and other useful illnesses. Kingston, ON: McGill-Queen's University Press, 2002.
Barsky AJ, Borus JF. Functional somatic syndromes. Ann Intern Med 1999;130: 910-21.
Stone J, Wojcik W, Durrance D, Carson A, Lewis S, MacKenzie L, et al. What should we say to patients with symptoms unexplained by disease? The "number needed to offend." BMJ 2002;325: 1449-50.
Evers S, Voss G, Nieman F, Ament A, Groot T, Lodder J, et al. Predicting the cost of hospital stay for stroke patients: the use of diagnosis related groups. Health Policy 2002;61: 21-42.
Brody H. The systems view of man: implications for medicine, science and ethics. Perspect Biol Med 1973 Autumn: 71-92.
Post MWM, de Witte LP, Schrijvers AJP. Quality of life and the ICIDH: towards an integrated conceptual model for rehabilitation outcomes research. Clin Rehabil 1999;13: 5-15.
Wade DT. Medically unexplained disability - a misnomer, and an opportunity for rehabilitation. Clinical Rehabilitation 2001;15: 343-7.
Halligan PW, Bass C, eds. Malingering and illness deception. Oxford: Oxford University Press, 2003.
Chin NP, Monroe A, Fiscella K. Social determinants of (un)healthy behaviors. Educ Health 2000;13: 317-28.(Derick T Wade, professor )
Correspondence to: D T Wade derick.wade@dsl.pipex.com
Current medical models assume that all illness is secondary to disease. Revision is needed to explain illnesses without disease and improve organisation of health care
Introduction
The model of illness adopted by society can have important consequences. In the first world war, for example, soldiers complaining of symptoms after experiencing severe stresses were sometimes shot as malingerers, but today they are considered victims and eligible for financial settlements Social acceptance that a behaviour or reported symptom constitutes an illness bestows privileges on an individual and formal duties on society.3
Currently, most models of illness assume a causal relation between disease and illness—the perceived condition of poor health felt by an individual. Cultural health beliefs and models of illness help determine the perceived importance of symptoms and the subsequent use of medical resources.4 The assumption that a specific disease underlies all illness has led to medicalisation of commonly experienced anomalous sensations and often disbelief of patients who present with illness without any demonstrable disease process.
Current models of illness
People often experience anomalous sensations.8 w9 The model of illness adopted will influence whether a person or their health adviser interprets a change in their state as indicating disease,9 when someone should enter and leave the sick role, and often the health care given. Only a small minority of potential symptoms lead to involvement with health care, but a small change in the rate of interpreting anomalous sensations as symptoms by any party will have a major influence on the use of healthcare systems.
Being ill, and being allowed to enter the sick role, has social and personal advantages for the person.3 Sick people may be absolved from social responsibilities, they are not held responsible for their condition, and they will often be eligible for healthcare benefits for which they do not pay directly. The sick role is most effective when it is validated by a doctor, but increasingly other health and non-healthcare professionals contribute to validation; indeed, ill people can now classify themselves as sick—for example, through self completed incapacity benefit forms in the United Kingdom.
Already many patients present with symptoms that are not attributable to any underlying pathology or disease.10 Nevertheless, such patients are often given a medical diagnosis, implying an underlying structural cause and reflecting cultural expectations.
Unfortunately, the use of diagnostic labels has implications for the patient, society, and ultimately for the credibility of medicine. Any illness provided with a (medically validated) diagnostic label is widely assumed to be secondary to defined pathology, to be capable of confirmation independently of the symptoms, and to have a specific treatment that health services should supply.
The problems arising from illnesses without a definable cause have been well documented.11 They are most appropriately termed functional somatic syndromes,12 w10 w11 recognising that psychological and social factors strongly influence the presentation of somatic symptoms.w12 However, suggesting that patients do not have a disease (pathology) to explain their illness may understandably upset them13 and creates difficulty for healthcare bureaucracy which relies on the patient's specific disease label.
Funding is determined by diagnosis (in health related groups or similar) and ignores the initial cost associated with diagnosis (patients present with problems, not diagnoses). It also fails to recognise that a major part of healthcare cost relates to disability.14 Resources are primarily allocated for the diagnosis and specific treatment of disease. Little attention is paid to other interventions despite good evidence of their effectiveness. Examples include the provision of equipment,w13 w14 the use of specialist multidisciplinary stroke rehabilitation units,w15 and the altering of patients' beliefs.w16 Most healthcare systems also assume that treatment after diagnosis is brief and acts quickly. Indeed, the medical model might more accurately be termed the surgical model, given the pre-eminence of surgery in popular culture and health organisation.
Finally, most biomedical models also seem strongly linked to primitive forms of intuitive mind-body dualism. Health commissioners, budgetary systems, healthcare professionals, and the public all act as if there is some clear, inescapable separation between physical and mental health problems, ignoring evidence that a person's emotional state always affects their function and presentation of physical symptoms.w17 w18 For example, separate services exist for people with physical disability and for those with mental health problems.
New model
This model has many implications (see table A on bmj.com). One characteristic of a systems model is that abnormalities in one system can occur without any of its components being faulty, and so the model explicitly predicts that illness will occur without discernable pathology. The mystery of non-organic or functional12 illness is no longer medically unexplained.17 This analysis does not deny the reality of the illness but rather provides the rationale and support for explanations and treatments that direct their focus to the non-medical reasons why people may feel ill.
This model also predicts that the effects of an abnormality may depend crucially on the characteristics of other parts of the system. For example, hip arthritis may become apparent only after a stroke affects the other leg. Consequently, reduction of illness may require intervention at several points, and indeed may not necessarily include removal of the main abnormality; this may explain the success of specialised stroke rehabilitation.w15
The model suggests that some resources should be focused on altering contextual factors. Evidence already supports this approach: teaching carers of stroke patients benefits both the patient and healthcare systemsw22 w23; changing social contextw24 may be effective—for example, reducing time off work with back painw25; altering personal context may help in some illnessesw26—for example, using cognitive behaviour therapyw16; and improving the physical context reduces expenditure on health care.w13
The role of personal choice, absent in many biomedical models of illness,18 is central to any progressive explanation of human behaviour: "People are rational, aware self creating agents of their own health... influenced by consciously chosen goals."19 Personal choice plays an important part in the genesis or maintenance of illness, particularly in and through the domain of activities.
This model also illuminates some of the current stresses within health care and illness related benefits systems. Systems focused on pathology (that is, hospitals) work in short time scales and ignore all patient context. However, they have to manage patients with activity limitations, in whom the time scale is longer and context is important. A coherent approach to rehabilitation inevitably requires action from other agencies such as social, housing, or employment services. When the characteristics (speed of priorities, available interventions) across organisational boundaries do not match each other or the needs of the patient, stresses may arise (often referred to as bed blocking in hospital).
Conclusion
Wade DT, Halligan P. New wine in old bottles: the WHO ICF as an explanatory model of human behaviour. Clin Rehabil 2003;18: 349-54.
World Health Organization. International classification of functioning, disability and health. WHO: Geneva, 2001.
Parsons T. The social system. Glencoe, IL: Free Press, 1951.
Kirmayer LJ, Young A, Robbins JM. Symptom attribution in cultural perspective. Can J Psychiatry 1994;39: 584-95.
Porter R. The greatest benefit to mankind. A medical history of humanity from antiquity to the present. London: HarperCollins, 1997.
Oliver M. Social work with disabled people. Basingstoke: Macmillan Press, 1983.
Engel GL. The need for a new medical model: a challenge for biomedicine. Science 1977;196: 129-36.
Turner J. Medically unexplained symptoms in secondary care. BMJ 2001;322: 745-6.
Smith R. In search of "non-disease." BMJ 2002;324: 883-5.
Carson AJ, Ringbauer B, Stone J, McKenzie L, Warlow C, Sharpe M. Do medically unexplained symptoms matter? A prospective cohort study of 300 new referrals to neurology outpatient clinics. J Neurol Neurosurg Psychiatry 2000;68: 207-10.
Malleson A. Whiplash and other useful illnesses. Kingston, ON: McGill-Queen's University Press, 2002.
Barsky AJ, Borus JF. Functional somatic syndromes. Ann Intern Med 1999;130: 910-21.
Stone J, Wojcik W, Durrance D, Carson A, Lewis S, MacKenzie L, et al. What should we say to patients with symptoms unexplained by disease? The "number needed to offend." BMJ 2002;325: 1449-50.
Evers S, Voss G, Nieman F, Ament A, Groot T, Lodder J, et al. Predicting the cost of hospital stay for stroke patients: the use of diagnosis related groups. Health Policy 2002;61: 21-42.
Brody H. The systems view of man: implications for medicine, science and ethics. Perspect Biol Med 1973 Autumn: 71-92.
Post MWM, de Witte LP, Schrijvers AJP. Quality of life and the ICIDH: towards an integrated conceptual model for rehabilitation outcomes research. Clin Rehabil 1999;13: 5-15.
Wade DT. Medically unexplained disability - a misnomer, and an opportunity for rehabilitation. Clinical Rehabilitation 2001;15: 343-7.
Halligan PW, Bass C, eds. Malingering and illness deception. Oxford: Oxford University Press, 2003.
Chin NP, Monroe A, Fiscella K. Social determinants of (un)healthy behaviors. Educ Health 2000;13: 317-28.(Derick T Wade, professor )