Cognitive determinants of treatment choice among cancer patients : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University

Decisions about whether or not to include non-conventional therapies in a cancer treatment regimen are potentially critical. An illness such as cancer, perceived to be life-threatening, inevitably raises existential questions which, in the present study, were posited to underlie the cognitive approach to treatment choice for cancer patients. The hypotheses tested in the study were that those who use non-conventional medicine will be more knowledgeable and have a more positive belief system about cancer, will be more interested in and motivated about health matters, will desire more personal control and assume more responsibility for their health and its treatment, and will be more intrinsically oriented in terms of meaning in illness and life. It was further hypothesised that the differences between those who use only conventional treatments and those who include non-conventional treatments will become more marked as the boundary between the two is altered to incorporate more non-conventional treatments in the conventional category, suggesting that patients' perceptions of the distinction varies from the medical establishment's view. An important underlying objective of the study included the exploration of the conceptualisation of meaning in life and its events in terms of intrinsic and extrinsic orientations. 212 adult participants, all having been diagnosed with any form of cancer for at least three months, volunteered and completed a postal survey. Overall, the results indicated that the conceptualisation of meaning as intrinsically or extrinsically oriented was an appropriate basis for exploring the role of existential issues in treatment decision making. The combination of constructs in the study was also confirmed as appropriate. In terms of the specific hypotheses, the expectation that users of non-conventional medicine would be more knowledgeable and more positive in their beliefs about cancer was supported only when conventional treatment was deemed to include certain physical and natural types of treatment usually labelled as non-conventional. Users of non-conventional medicine were found to be more interested in and more motivated to be involved in health matters than those who used only conventional medicine. They were also found to be those who desired more personal control over their health and its treatment and were also prepared to assume more responsibility. The results also supported the hypothesised difference between conventional only and non-conventional users in terms of intrinsic life meaning, but results for extrinsic life meaning only partially supported the expectation that this would be associated with conventional medicine use. These were discussed in terms of measurement issues and the reconceptualisation of the religious, spiritual and philosophical derivations of extrinsic meaning. No difference was found between users of conventional only and users of non-conventional medicine in terms of illness meaning, suggesting that conceptualisation in intrinsic and extrinsic terms was inappropriate for this sub-construct. There was also support for the view that treatments are viewed by many as being on a continuum from conventional to non-conventional, rather than being in defined dichotomous groups. Multivariate results (from a series of 2-group discriminant analyses) confirmed that health interest and motivation, attributions of control, responsibility and blame, and intrinsic and extrinsic meaning in life were the most important contributors to discrimination. Internal control attributions were consistently the most important relative discriminator. These results also showed that the influence of the discriminating variables in combination, including sociodemographic control variables, explained variances ranging from 25.4% to 33.6% across the altered groupings of treatment type. The results are discussed in relation to the conceptualisation of meaning and attributions of control and responsibility as pivotal concepts, and in relation to the indication that the greatest separation between conventional and non-conventional use was found when certain physical and natural treatments were classified as conventional rather than non-conventional. Psychometric, and conceptual limitations of the study are discussed, suggestions for future research are made, and some applications of the findings for health professionals are offered