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Theoretical Perspectives on Health and Illness
A formal, comprehensive definition of health was adopted in 1946 in the original constitution of the World Health Organization (WHO): "Health is a state of complete physical, mental, and social well-being and is not merely the absence of disease or infirmity." This definition represents efforts to conceive health in positive terms rather than as the absence of poor health status and in relation to psychological, physical, and social dimensions. Although such a concept is most closely related to the psychological orientation toward health endorsed in this book, it is embraced by other disciplines concerned with health and health-related activities (e.g., social medicine, epidemiology, and medical sociology). The interdisciplinary nature of this concept is reflected in the various theoretical models of health that are briefly outlined in this chapter. It will become clear that developmental aspects are largely neglected in most theoretical approaches toward studying health. Thus, models that explicitly follow a developmental psychological perspective are highlighted, especially those that attempt to explain the relationships between healthy or normal and ill or pathological processes, as have, for example, been worked out in the field of developmental psychopathology.
Subjective Concepts of Health and Illness
A major problem in understanding subjective concepts of health and illness is related to the fact that they are strongly influenced by social or normative factors, that is, society dictates how healthy or ill people should feel and biologically function. Also, subjective concepts of health greatly vary from individual to individual. Furthermore, children's, adolescents', and adults' beliefs and assumptions about these concepts dramatically differ, often in unexpected ways. Unfortunately, subjective concepts of health and illness often are vastly different from the operational definitions used by health care professionals and investigators who are often unaware of how differently individuals construe health and illness, depending on their developmental stage.
Lay Conceptions of Health and Illness
Subjective concepts of health have not been investigated very often, although they undoubtedly play an important role in how an individual concretely deals with health and illness. One reason may possibly be related to the unconscious attitude most people have about health: Good health is simply taken for granted and only becomes salient when one loses it. Many people think of health as solely being the absence of illness. For example, a Scottish study on persons over 60 years old found that the key dimensions of health mentioned were an absence of illness, a reserve of strength, and a feeling of being generally fit or capable of accomplishing daily tasks (Williams, 1983). Corroborating evidence comes from a study of middle-aged French subjects, who described health in terms of an absence of illness, an equilibrium in daily life, and a capacity to work (Herzlich, 1973; Herzlich & Pierret, 1987). Other researchers found that although both working-class and middle-class people shared the notion that health meant the absence of illness, working-class people tended to emphasize what was essential for their everyday lives: the ability to carry out their daily tasks, especially job and family duties. Middle-class people were more likely to have broader, positive concepts of health that included such factors as energy, positive attitudes, and the ability to cope well and be in control of one's life (Calnan, 1987; Herzlich, 1973). In a study of more than 4,000 people, D'Hontand and Field (1984) found that health concepts varied considerably according to the respondent's socioeconomic status (SES): Skilled workers viewed health in instrumental, negative terms ("absence of illness" or "performance deficit"), whereas individuals with more extensive academic backgrounds viewed health as a personal goal and a state of psychosocial well-being ("happiness").
There are also strong gender differences in people's ordinary concepts of health, especially between mothers and fathers (Versteegen, 1988). Mothers consider their health to be an essential resource; nevertheless, they invest more efforts in protecting and maintaining their children's health than their own. Research has demonstrated, too, that although most individuals have difficulties in articulating their subjective concepts of health, they are quite able to make relatively concrete statements about health-preventive behaviors, such as watching one's diet, getting enough sleep, pursuing athletic activities, relaxing, going for medical checkups, avoiding consumption of health-damaging substances (e.g., cigarettes, alcohol, or drugs), and maintaining social contacts (Freund & McGuire, 1991).
Just as laypeople's notions of health are shaped by their social and cultural background, so too are the ways people understand illness. Individual beliefs about illness are typically drawn from larger cultural belief systems that shape the illness experience, help the individual to interpret what is happening, and offer a number of choices about how to react. Lay conceptions of illness also dictate how an individual responds to disease. For example, a study of middle-class Americans found that people regularly referred to diseased body parts as if they were objects separate from the person (Blaxter, 1983). The concept of disease as a foreign entity reflects a common tendency to understand disease as being caused by some external agent that has invaded the body. Indeed, most people think of disease in terms of what one has, gets, or catches. The causal categories most commonly named in several studies are (a) infection; (b) hereditary or familial tendencies; (c) environmental agents (e.g., toxic wastes or poisons), working conditions, and climate; (d) secondary effects of other diseases; and (e) stress, strain, and worry (Freund & McGuire, 1991). Although causal categories used by lay people may not be correct in medical and biological terms, they are generally rational and are based on the kinds of empirical evidence available to them. In addition, the interpretation of illness is an ongoing process. People reappraise their conditions throughout the various stages of illness.
Developmental Changes in Conceptions of Illness and Health
A number of investigators studied the development of children's conceptions of health and illness. Most studies have been based on developmental theory as worked out by Piaget. Accordingly, attempts have been made to identify a general congruence between children's conceptions about health and illness and stages of cognitive development, especially with respect to reasoning concerning the physical world. For example, Bibace and Walsh (1981) interpreted the development of health concepts for younger children according to the three broad stages of cognitive development outlined by Piaget (i.e., preoperational, concrete operational, and formal operational). Most younger children (i.e., those between 4 and 7 years old) consider illness to be a magical phenomenon or an act of sorcery; they sometimes view illness as punishment (e.g., the consequence of disobeying their parents). In this developmental period, children begin to acquire an understanding that illness is transmitted from an external source to their own bodies. Nevertheless, they are not always able to understand or explain how illness is spread or they overgeneralize the principle of infection, believing that all illnesses are contagious. In middle childhood (from 7 to 11 years old), children accept the germ theory of illness etiology (i.e., that illnesses are transmitted by germs) but understand that not all illnesses are infectious. They accept a limited number of factors that enhance or reduce the possibility of illness. At about 11 years old, children understand that illness is related to the fact that bodily organs are not functioning properly. At around 14 years of age, they know that an illness may also result from emotional stress. Around the same time, they understand that ordinary definitions of illness also include aspects of a sick person's role (i.e., how someone acts after having been designated as sick). Thus, only when the child has reached the formal operational stage of cognitive development and has acquired more knowledge about internal physiological structures and functions is he or she able to approach understanding illness in terms of complex physiological and
TABLE 1.1 Child and Adolescent Definitions of Illness
| Topics | Adolescents | Children |
| Nonlocalized general feelings: "I feel bad." | 39.9 | 60.3 |
| Nonlocalized, specific feelings: "It hurts," "It's sensitive," "I'm dizzy." | 51.9 | 36.6 |
| Localized physical sensations: "I have a headache." | 42.9 | 46.2 |
| Visible signs: "Joints are swollen." | 15.6 | 11.5 |
| Objective but not visible signs: "I have a headache." | 5.2 | 12.6 |
| Illness concept: "Appendicitis." | 10.4 | 9.5 |
| State of feelings: Tm grumpy, lethargic." | 9.1 | 11.8 |
| Sick role behavior: "I go to bed." | 9.1 | 13.0 |
| Changed conventional role: "I don't go to school." | 28.6 | 10.7 |
| Behavior of others: "The doctor comes." | 2.6 | 8.8 |
| Explicit restrictions: "When I have a cold, I'm not sick." | 0.0 | 2.3 |
psychophysiological processes (C. Eiser, 1985). As Table 1.1 illustrates, the meaning of specific feelings, as well as the inclusion of changed behaviors related to illness or characteristics of a sick person's role, represent some of the most important differences between definitions of illness made by children and early adolescents according to the study of Millstein, Adler, and Irwin (1981).
Observations made about children and adolescents in the hospital setting, documented by A. Freud and Bergmann (1965), shed light on how differently children and adolescents interpret and react to illness and infirmity. Younger children, who are expected to interpret illness as a consequence of disobeying their parents, often felt quite guilty about being ill. For example, they often explained their poor health to be a result of playing outside in the cold without a jacket, although their parents had instructed them to dress warmly. Slightly older children, who would be more likely to accept the germ theory of illness, were extremely careful not to come into physical contact with other ill children. The explanations for illness clearly became more differentiated among the 10- and 11-year-old children, who understand that illness is sometimes caused by bodily organs that do not function properly. Freud and Bergmann described the vigilance with which young patients with heart disease observed the amount, shape, and color of the pills the nurses gave them. Aside from the perceptible changes in heart functioning, these children assessed the gravity of their illness according to the amounts of medication they were required to take. Patients on the orthopedic ward tolerated the long periods of immobilization especially because the physiological reasons for their infirmity were concretely visible and they understood the rationale behind the therapeutic measures involved.
Other empirical studies on the development of health and illness conceptions have shown that both conceptions become differentiated in childhood and adolescence and that this development is associated with personal experiences with illness. For example, Millstein and Irwin (1987) interviewed 11- to 18-year-old adolescents and found that health and illness were different, yet overlapping, constructs. Children's definitions of health and illness became more precise with increasing age, and the focus changed as well. The younger respondents' definitions of health were more strongly bound to personal experiences with illness. In contrast, older adolescents' definitions included more references to physical well-being, the fulfillment of social- and achievement-related norms, and preventive health behaviors. In another study, adolescents typically viewed health as being more than simply the absence of illness: Being healthy meant living up to one's potential, being able to function physically, mentally, and socially, and experiencing positive emotional states (Millstein & Litt, 1990). In fact, "not being sick" accounted for less than 30% of the contents making up adolescents' conceptions of health. Thus, their definitions were more similar to adult conceptions of health and paralleled the formal definition of health laid down by the WHO.
In adolescents, illness and being sick are directly experienced by the manifestation of more or less frequently occurring symptoms of illness. As outlined earlier, their conceptions of health go beyond not being sick and include a variety of aspects of physical, psychological, and social well-being. It should also be pointed out that adolescents often perceive adult encouragement to lead a healthy lifestyle or engage in health-promoting behaviors as attempts of adults to regulate their lifestyles and restrain them from their spontaneous urges to eat, drink, and enjoy the pleasures of life at their will. Indeed, for many adolescents, experiencing health in the sense of well-being includes engaging in various behaviors that are hazardous to their health or are directly opposed to the adult conceptions of illness prevention, in the sense of risk avoidance or reduction. In addition, especially early adolescents sometimes underestimate their potential for becoming ill or injured. This is partly related to the fact that adolescents, due to their lower risk for illness, have generally had little experience with impaired health. Although they share this experience of low risk for illness with children, increased egocentrismāwhich reaches its greatest levels between 12 and 15 years old and decreases thereafterācontributes to this fallacy of judgment (see chap. 2, this volume). During this age span, adolescents believe they are relatively immune to sickness and injuries. After 16 years old, a more realistic perception of risks develops and adolescents begin to acknowledge and avoid health risks.
Additional changes in the development of conceptions of health and illness in adolescence are related to the sick role and the disruption of control. Although adolescentsācompared to childrenārecognize the sick role as a characteristic of illness, they may not be able to submit to this role easily. Most illnesses disrupt an individual's ability to exercise control, and being disabled or dependent on others can be especially threatening to the adolescent who is making great efforts to achieve independence.
Theoretical Models of Health and Illness
We are now ready to consider theories generated in the frameworks of various academic disciplines about health and illness. Medical, sociological, and psychological theories are presented and analyzed according to their suitability for a general conception of health in adolescence. It should be emphasized here that the models discussed in this section are oriented toward explaining the general concepts of health and illness; other models that incorporate aspects of health-related behavior, for example, as related to seeking professional care and treatment, are discussed later (see chaps. 8 and 9, this volume).
Medically Oriented Models
One of the more classic medically oriented theoretical approaches toward understanding health has its origins in the field of virology. The risk-factor model (Abholz, Borgers, Karmans, & Korporal, 1982) is based on the assumption that each illness has a specific cause and is associated with overtly manifest symptoms and physical damage or injury. In its original form, this model proved to have several inherent weaknesses, as Levi (1975) pointed out. For example, it fails to explain why some individuals do not contract an illness, despite exposure to a pathogenic agent.
More recent medical models attempt to compensate for these weaknesses. Compared to earlier models, they are more complex and accommodate for a variety of factors that influence health and health-related behavior. A more comprehensive understanding of health and illness is characteristic of these models. Health and illness are regarded as states determined or influenced by many variables (e.g., the risk of becoming ill and the onset and course of illness being determine...