An Exploration of Men's Decision Making and Decisional Conflict after Localised Prostate Cancer
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The aim of this thesis is to describe how men with localised prostate cancer make decisions about their medical treatments, to describe the psychological and decision-related adjustment of these men over time, and to identify what variables predict decision-related adjustment. Chapter 1 reviews the medical context of localised prostate cancer and factors that influence men's decision making in this context. It is concluded that owing to ongoing uncertainty about the optimal medical treatment for this cancer and the substantial negative quality of life effects of treatments, how men make decisions in this context is an important research question. Further, although men with prostate cancer are high seekers of medical treatment information, knowledge about how men use such information and actually make this treatment decision is limited. Chapter 2 discusses research approaches currently applied to patient decision making: first, a social interaction approach encompassing the interaction between the patient and their physician and the social context influencing this interaction (Charles, Gafni, & Whelan, 1999); and second, normative decision theory (Shafir & Tversky, 1992; von Neumann & Morgenstern, 1947). The Heuristic-Systematic Processing model (Chaiken, 1980) is then proposed as a theoretical framework for investigating patient decision making that includes both systematic and non-systematic decision strategies. Chapter 3 reviews applied decision research in cancer, and presents an overview of research findings regarding patients' preferences for involvement in decision making, the relationship between decisional involvement and psychological adjustment, and decisional support interventions. Research on adjustment to cancer is discussed and the need for further research about men's psychological and decision-related adjustment after localised prostate cancer is identified. Finally, a multivariate analysis of decision-related adjustment for men with localised prostate cancer based on the stress and coping framework of Lazarus and Folkman (1984) is proposed. Chapter 4 describes Study 1 that was an experiment to investigate the utility of the Heuristic-Systematic Processing model (HSM) in explaining low desire for involvement in decision making about prostate cancer treatments as an example of use of the expert opinion heuristic. Using a hypothetical decision scenario about localised prostate cancer it was found that a low desire for involvement in decision making by men was predicted by a high belief in powerful others controlling health, a low belief in the self being responsible for good health, a high preference for black and white thinking, and a lower level of education. This study provides preliminary support for use of the HSM in this context and for the conceptualisation of decision deferral as the expert opinion heuristic. Chapter 5 introduces and describes the method of Study 2 that was a descriptive, prospective study of men's decision making after an actual diagnosis of localised prostate cancer. This method allowed for an analysis of men's decision making that includes both systematic and non-systematic processes, and for further investigation of the utility of the HSM in explaining decision behaviour. In addition, a multivariate approach was used to describe men's physical, psychological and decision-related adjustment over time, and to identify psychological predictors of decision-related adjustment. Chapters 6 describes men's use of systematic processing as limited and the use of non-systematic processes, such as lay beliefs and heuristics, as pervasive. It is concluded that patients do not utilise information about medical treatments in a comprehensive or systematic way when making treatment decisions and that patients' decision making is biased by their prior beliefs about cancer and health. A framework is outlined to demonstrate how the results of Study 1 and 2 support the application of the HSM to decision making about prostate cancer with particular reference to the role of beliefs about the physician, health locus of control, and uncertainty about the treatment decision in influencing decision strategies. Chapter 7 describes men's physical, psychological and decision-related adjustment over time, and concludes that decision-related distress is high but psychological distress in general is low. Decisional conflict at diagnosis and at twelve months concurrently, and at two months prospectively, was predicted by dispositional optimism; and this effect was mediated by the man's proximal cognitive appraisal of the impact of the cancer. It is concluded that decisional conflict is a person's cognitive judgment of the treatment decision that is generated by similar processes to that of the psychological distress that follows a cancer diagnosis. Conclusions and implications of these studies for future research in this area are summarised in Chapter 8.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Applied Psychology (Health)
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