Intended for healthcare professionals


Moving beyond single and dual diagnosis in general practice

BMJ 2003; 326 doi: (Published 08 March 2003) Cite this as: BMJ 2003;326:512

Many patients have multiple morbidities, and their needs have to be addressed

  1. Nat Wright (nat.wright{at}, general practitioner consultant in substance misuse and homelessness,
  2. Liam Smeeth (liam.smeeth{at}, clinical lecturer,
  3. Iona Heath the Royal College of General Practitioners Health Inequalities Standing Group (pe31{at}, general practitioner
  1. No Fixed Abode Health Centre for Homeless People, Leeds LS9 8AA
  2. Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT
  3. Caversham Group Practice, London NW5 2UP

    The awkward phrase “multiple morbidity” describes the common predicament of the many patients who have more than one health problem. Such patients are disproportionately represented among populations that are socioeconomically deprived and elderly.1 A socioeconomic gradient exists in the incidence and prevalence of almost all major categories of disease, meaning that individuals and families who are socioeconomically disadvantaged are at risk of a compounding multiplicity of health and social problems.2 This multiple morbidity, coupled with the fact that the population of the United Kingdom is ageing,3 poses challenges to the delivery of effective health care that have received almost no official attention.

    Examples from mental health show that provision of service in this field has been slow to move from single diagnosis to dual diagnosis.4 Dual diagnosis applies to patients who have a mental health problem and problematic substance or alcohol use. A recent report on dual diagnosis from the Department of Health highlighted the role that primary care had in ensuring adequate care pathways for patients with mental health problems, drug problems, and related physical problems such as infection with hepatitis B or C virus or HIV.2 The report highlighting the issue of dual diagnosis did not use the term “multiple morbidity” to describe these patients. We believe, however, that such a term accurately describes the multitude of health need. It is our purpose to highlight this need so that effective policy measures can be taken to ensure adequate service provision for this complex group of patients.

    Effect of specialisation

    In the United Kingdom, hospital based clinical practice has become increasingly specialised.5 It is now usual for a single patient to receive care from several specialists, where previously they would have received care from a single general doctor. For example, a patient could be under the care of a nephrologist for renal disease, a cardiologist for coronary heart disease, and a respiratory doctor for chronic pulmonary disease. The extraordinary advances in medical knowledge and the overwhelming volume of relevant scientific literature mean that specialisation may be a requirement for optimal management of some diseases. However, the trend towards more specialisation in secondary care tends to disadvantage people with multiple morbidity. The effective management of such patients depends heavily on general practice.

    The changes in general practice have the potential to support or undermine the care of patients with multiple morbidity. Most general practitioners now either work as independent contractors to or are salaried employees of primary care organisations. In England and Wales primary care organisations are anticipated to hold at least 75% of the NHS budget to pay for their patients' use of hospital, primary care, and community services; and prescribing costs.6 Additionally they are able to hold social care budgets under the delegated authority of local authorities.7 Poor health is inextricably linked to low income or unemployment, poor housing, and inadequate social support. A unified budget for health and social care could enable a more effective approach to these wider structural causes of health inequalities.

    But it is not just poor collaboration between primary care services and social services that threatens the effective management of people with multiple morbidity. The boundary between primary and secondary acute care sectors has placed bureaucratic and fiscal obstacles in the way of the coordinated care of patients with multiple problems.8 9 Current best practice for commissioning of secondary care services by primary care organisations seeks to analyse pathways for care for patients.10 As a result, some innovative primary care organisations have sought to avoid the problem of the barriers to primary care or secondary care by general practitioners taking on an extended role in an area of special clinical interest. However, at present such a referral pathway to a general practitioner with a special clinical interest is for a single condition, and therefore a patient with multiple problems will still require multiple referrals.

    Effective projects for the general practitioners with a special clinical interest will need to find ways not only of reducing the number of referrals across the interface between primary care trusts and acute trusts but also of reducing the total number of referrals needed in primary care. Ways need to be found in which general practitioners can be supported by a range of specialist experts to provide effective care for patients with complex and overlapping health problems.11

    Similarly, medical students need education, which equips them to meet the challenges posed by such care. Again, this can best be achieved in a generalist setting. One consequence of the increasing specialisation of hospital based doctors is that in the United Kingdom, medical students are increasingly taught by superspecialists with expert knowledge in a narrowly defined focus on a disease. Although such teaching will bring an immense depth of knowledge to that disease, it runs the risk of overlooking the complexities of clinical management of multiple morbidity. Although the proportion of primary care based undergraduate teaching has increased, in some medical schools such teaching still forms only 4% of the total.12

    Effect of cost containment

    Another threat to the role of primary care in addressing problems of multiple morbidities is the unresolved tension between high quality care and the statutory responsibility on primary care organisations to contain costs.5 On the one hand it is preferable, for example, for older people with multiple needs to receive health care in their own communities from “generalist general practitioners.” On the other hand, the intention behind such care has been to achieve cost savings, which have in turn undermined both the volume and the quality of care delivered. One approach to cost containment is to “cherry pick” patients whose costs are high and select them out of receiving health care from the primary care organisations.1 Interestingly, when fundholding was a part of primary care commissioning, homeless people with multiple morbidity were less likely to be registered with a fundholding practice.13

    The evidence to inform the care of patients with multiple problems compares poorly with the evidence supporting single interventions for single diseases. It is unlikely we will ever have randomised controlled trials to guide optimal treatment—for example, for people with paranoid schizophrenia, liver damage related to chronic hepatitis C, and epilepsy, who are living alone in a damp flat. Similarly, while randomised trials usually measure the effects of one, or occasionally two or three, interventions, it is usual for patients' with multiple morbidity to be taking eight or more drugs. Polypharmacy was rightly highlighted as an important issue in the national service framework for older people, and clearly this is not just an issue for general practitioners. As general practitioners it is our job to manage all of a patient's health problems, by drawing on help from specialists where we can and by using whatever research evidence exists to guide practice.

    Patients with more than one health problem constitute a large proportion of the workload in primary care. Multiple morbidity is a major component of health inequalities, particularly in an ageing population, and can be seen in part as a direct consequence of the wider societal determinants of ill health. Health care that is both driven and evaluated increasingly by protocols derived from studies of single disease conditions seems likely to disadvantage systematically those with complex and overlapping health problems. An urgent need exists to know more about the optimal treatment of multiple morbidity. How should the care of different diseases be prioritised in situations where treatments are incompatible or the burden of treatment becomes too great? If government and policy makers are serious about tackling health inequalities, a more coherent approach to the problems posed by multiple morbidity is required.


    • Competing interests None declared.


    1. 1.
    2. 2.
    3. 3.
    4. 4.
    5. 5.
    6. 6.
    7. 2002.
    8. 7.
    9. 8.
    10. 9.
    11. 10.
    12. 11.
    13. 12.
    14. 13.
    View Abstract