Applied Fields: Health

Introduction

Health psychology is a field within psychology that is devoted to understanding psychological influences on health-related processes, such as why people become ill, how they respond to illness, how they recover from a disease or adjust to chronic illness, and how they stay healthy in the first place (Schwarzer & Gutiérrez-Doña, 2000). Health psychologists conduct research on the origins and correlates of diseases. They identify personality or behavioural antecedents that influence the pathogenesis of certain illnesses. Health psychologists analyse the adoption and maintenance of health behaviours (e.g. physical exercise, nutrition, condom use, or dental hygiene) and explore the reasons why people adhere to risk behaviours (e.g. why they continue to smoke or drink alcohol). Health promotion and the prevention of illness are, therefore, agendas for research and practice, as is the improvement of the health care system in general.

In health psychology, a multitude of variables are assessed, such as physical conditions, health behaviours, quality of life, coping with stress or illness, coping resources, and premorbid personality. Since health behaviours dominate the discipline, the following contribution will focus on this particular subarea.

Health Behaviours

Many health conditions are caused by such behaviours as problem drinking, substance use, smoking, reckless driving, overeating, or unprotected sexual intercourse. Health behaviours are often defined as behaviours that people engage in to maintain or improve their current health and to avoid illness. They include any behaviour a person performs in order to protect, promote, or maintain his or her health, whether or not such behaviours are objectively effective towards that end (Conner & Norman, 1996; Schwarzer & Renner, 2000).

People are inconsistent in the way they practise multiple health behaviours. For example, a person who exercises regularly does not necessarily adhere to a healthy diet. One reason people's current health habits are not more consistent is that they differ on a number of dimensions (see Table 1).

For a valid and reliable measurement of health behaviours, it is essential to distinguish between these dimensions and to define clearly the subject matter under investigation.

Assessment of Health Behaviours

There are various methods of assessing health behaviours (Renner, 2001). Questionnaires that assess the frequency of past behaviour are the most commonly used methods. There are numerous questionnaires that ask for the average or typical quantity and frequency of alcohol consumption (for an overview, see Sobell & Sobell, 1995), dietary habits, or physical activity. However, the information provided by quantity and frequency measures (QF estimates) is limited because respondents must base their estimates on a large variety of experiences. QF estimates often reflect less drinking and tend to misclassify drinkers compared to daily diary or timeline reports. They also provide lower absolute food intake estimates than a longer, interviewer-administered diet history.

In rare occasions, physiological methods can be used, which are most accurate for measuring alcohol consumption (via blood or urine sampling), drug consumption (via immunoassay, hair or sweat bioassay procedures), habitual dietary intakes (via biochemical markers), or physical activity (via doubly labelled water). However, such bioassay methods are only required when a high level of accuracy about recent health behaviour is needed (e.g. for workplace drug testing). They can also be used in addition to self-report data in order to confirm or falsify self-report information (e.g. about recent drug use). However, in some circumstances it may only be necessary to lead respondents to believe that there is an objective way to identify their behaviours via physiological measures, which is done to reduce misreporting. Another direct method is behavioural observation, used to assess physical activity among children or a driver's speed, for example.

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