ABSTRACT
Human behavior is at the centre of much research in the health domain because of its potential contribution to the myriad of medical conditions that afflict people every day. The detrimental health effects of cigarette smoking, alcohol and drug abuse, lack of exercise, poor nutrition, and so forth are well documented (see Stroebe, 2000). These lifestyle behaviours increase, among other things, the risk for various types of cancer, emphysema, coronary heart disease, diabetes, osteoporosis, and sleep disorders. Besides raising morbidity, these behaviours can also have a generally detrimental impact on quality of life. In the first part of this chapter we use a reasoned action approach, the theory of planned behaviour (Ajzen, 1988, 1991), to examine the causal antecedents of health-related behaviours, asking why people perform, or fail to perform, recommended health practices. A good understanding of these antecedents is of interest in its own right but, equally important, it is essential for designing effective intervention programmes, a topic we address in the second part of this chapter. We illustrate the potential utility of the theory of planned behaviour in this regard and then focus on one particular problem faced by any reasoned action approach, the question of behavioural routines, habits, and addictions.
