Disease versus illness: What do clinicians need to know?

The distinction between disease and illness is often not recognised clearly and both are seen as meaning the same. That may indeed be the case in colloquial terms, but confusion often exists in medical and certainly in psychiatric circles.

Eisenberg (1977) very clearly and elegantly made the distinction between the two concepts. He defines disease literally as dis-ease, meaning that it deals with pathology, which is what doctors are trained to identify and manage. On the other hand, illness is what patients are interested in, as the impact of disease occurs on their functioning, relationships and social interactions. In an interesting aside, Eisenberg (1977) highlights the Cartesian mind-body dualism which was liberating at the time of its pronouncement but has become more restrictive over the centuries. This is particularly true in our understanding of the chasm perceived between physical and mental disorders. Eisenberg goes on to define illness as experience of disvalued changes in the state of being and in social function, whereas diseases – especially in the context of health care systems – are related to abnormalities in structures and functions both of body organs and body systems. The tension thus is between the patient perspective, which focuses on illness, and the doctor perspective, which often concentrates on diagnoses of diseases. This also means that illness experiences are treated in personal, folk and social sectors (Kleinman & Eisenberg, 2006). Thus, they argue that contemporary medical practice has become distant; with ever increasing technological advances such as mobile phone apps, this distance is likely to increase further not really decrease. They go on to caution that neither disease nor illness should be seen as distinct entities. Patients may find it acceptable to live with their symptoms as long as they are able to function and have relationships. The difficulties resulting from disease transformed into illness should not be separated clinically. Biomedicine appears to have banished the concept of illness. Using the same distinction of disease and illness in primary care, Helman (1981) highlights that the illness also includes the meaning given to the experience. Primary care physicians in a similar way to psychiatrists can understand the interface between the social and medical factors which can then be utilised in creating a common understanding as well as therapeutic alliance. Carel (2013, p. 94) points out that as the medical focus ignores concepts of illness and focuses on a negative deficit approach, the positive experience of health within illness remains unacknowledged. This is an observation which needs further exploration, as more individuals are living with chronic conditions and co-morbidities. Even within the context of psychiatry, if an individual has recurrent depression or bipolar disorder, it is worth remembering that in between the episodes, the individual may well be symptom-free.

In her account of illness, Carel (2013) reminds us that the description of the lived experience as explained by phenomenology should be seen as a challenge to the medical world, which notes and deals with a different perception and description of disease in contrast with that of illness. Phenomenology undoubtedly places importance on a thoroughly human environment of everyday life and presents thus a view which is both personal and (therefore) novel. We know from clinical experience that no two patients will experience or explain their (somewhat) similar symptoms of hallucinations or delusions in the same way. Their explanation of what they are undergoing will vary according to their cultures, cultural world view and educational, social and economic status. Illness, according to Carel (p. 10), is not a biological explanation of dysfunction, but illness is a way of living, experiencing the world and interacting with other people; phenomenology attends to the global disruption of the habits, capacities and actions, and thus the focus has to be on the lived experience.

Carel (2013, pp. 12–13) raises a very interesting point when she notes that in the past three decades or so, two approaches to illness have emerged. These are naturalistic (prevalent in the medical world where disease equates with biological dysfunction) and normativist (using common social terms to capture a particular phenomenon where the focus is on how society perceives the ill person), by feeling sorry for such individuals and offering them sick leave as an option to rest and recover. As a result of illness, the physical and the social worlds of the individual change. The social world of illness may also involve doctors and health professionals. The social architecture of illness changes self-perceptions. Carel (2013) argues that whereas the healthy body is transparent, the ill body is visible.

In chronic conditions and co-morbid conditions, the definitions and understanding of health and ill health may need to be revised. The original World Health Organization (WHO) (2006) definition of health as the absence of disease requires rethinking. It is inevitable that in many chronic conditions, relapse may get the individual to a healthy status even though illness may continue to lurk in the background. The importance of living with symptoms while continuing to function at a reasonable level cannot be underestimated.

Health within illness needs a clear account of what the individual is doing. Chronic illness is often misconceived within the framework of acute care, with the view of illness as simply a temporary disruption of self rather than as a condition (Carel, 2013, p. 90). Carel suggests that because the medical model focuses on disease and a negative deficit approach is applied, the positive experience of health within illness remains unacknowledged within clinical practice probably because such experience often does not fit within the academic training. Thus, illness may be seen as having certain positive connotations. In some cultures, individuals with mental illness are revered.

Eisenberg (1977, p. 12) points out that changing patterns of symptom presentation in military personnel reflect cultural shifts in the response to stressful stimuli. Littlewood (1991) suggests that dissatisfaction with excessive emphasis (by the medical profession) on disease has led to individuals seeking help from complementary and alternative practitioners (who may give more attention to the process of being ill and understand the role of social factors).

There are many lessons for clinicians and educators of medical students and trainees in psychiatry. We need to bring medical humanities and medicine together in order to create a discipline of medicine which amalgamates science and art, so that the individual with distress remains at the core of any therapeutic interaction. The explanatory models of the individual who is distressed and of those who care for them and thus engage them in therapeutic endeavours become significant in improving outcomes.