Illness representations, coping, illness outcomes, and support needs of people with cancer and anxiety/depression

Cancer and anxiety/depression commonly occur as co-morbid conditions, leading to poorer health and illness outcomes as well as reduced quality of life in those affected. However, currently too little is understood about the impact of this combination of illnesses. In order to determine how people with cancer and anxiety/depression can be best supported to improve health and illness outcomes, as well as to identify what supports and services they may need, it is important to understand the psychological processes underlying coping behaviours and illness outcomes for people with each illness separately and for those with combinations of cancer and anxiety/depression. This thesis therefore aimed to firstly examine how the illness representations of people with cancer (Study 1) and of people with depression (Study 2) separately influenced coping responses and illness outcomes. Secondly, this thesis aimed to examine how having a combination of cancer and anxiety/depression would influence illness representations, coping and self-management behaviours, and support needs (Study 3), as well as how such support needs might differ across cancer patients with varying histories of anxiety/depression (Study 4). The leading psychological model of self-regulation in the face of illness is Leventhal's Common Sense Model of health and illness (CSM), which assumes that people form and access subjective representations of their illness based on common-sense assumptions. These idiosyncratic representations then guide individual coping attempts and processes. The CSM's illness representation dimensions have been found to be reliably associated with coping and outcomes for a variety of chronic illnesses. However, although several studies have investigated these relationships in people with cancer, no systematic review and meta-analysis to summarise these associations had yet been conducted. The same lack of a systematic overview of the evidence was also found for anxiety/depression. Based on these existing gaps in the literature, two separate systematic reviews and meta-analyses were conducted to determine the strength and direction of the relationships between illness representations and coping behaviours as well as illness outcomes in people with cancer (Study 1) and in people with depression (Study 2). The systematic literature search for Study 1 located 54 studies, with 38 providing sufficient data for meta-analysis and 16 narratively reviewed, while the literature search for Study 2 located 19 studies, with 10 included in the meta-analysis and nine narratively reviewed. During the systematic review process for Study 2 only one study examining illness representations in people with anxiety was located, making a review of people with anxiety impossible. Both reviews found substantial relationships between illness representations and coping as well as illness outcomes, with findings suggesting that for people with cancer and for people with depression, higher identity (more symptoms), a more chronic and cyclical timeline, more severe consequences, less personal and treatment control, less illness coherence, and stronger emotional representations were associated with maladaptive coping strategies and increased psychological distress. This evidence base served as a starting point for the second set of studies in this thesis. As cancer and anxiety/depression commonly co-occur, whether and how the CSMs illness representation dimensions were associated with coping and outcomes in people with multimorbid cancer and anxiety/depression was explored. As no research had yet investigated the multimorbid representations of people with cancer and anxiety/depression specifically, Study 3 included 21 semi-structured interviews and used theoretical thematic analysis to examine the structure and content of individual's representations of co-morbid cancer and anxiety/depression, as well as how these related to coping and self-management. This study found that participants most often perceived their cancer and anxiety/depression as related, with these interactions often considered causal (albeit with heterogeneity in which illness caused the other). In terms of illness representations, personal control and illness coherence emerged as important determinants of illness behaviour, with these representations shown to have both positive and negative influences on coping and self-management. These results suggested that better understanding of multimorbid representations by health professionals have the potential to lead to improved self-management strategies and health care interactions for people with cancer and anxiety/depression. As Study 3 began to identify differing support needs across people with cancer and anxiety/depression, Study 4 used inductive thematic analysis on data obtained from 21 semi-structured interviews to examine how the existing needs and supports of this population differed based on experiences of varied histories of anxiety/depression (e.g., episodic versus long-term). This study found important differences across cancer patients with varying histories of anxiety/depression, with people who had a history of long-term anxiety/depression that was not associated with cancer generally coping better, experiencing less fear of cancer recurrence, and requiring less support from hospitals and support services. These results highlight a need for both researchers and health professionals to give more consideration to the origin and history of a cancer patient's anxiety/depression in order to facilitate better coping and improve and increase appropriate support provision across cancer diagnosis, treatment, and survivorship. Overall, across the research in this thesis, subjective illness representations such as personal control, consequences, timeline, and illness coherence, have been found to be important predictors of coping behaviours, self-management strategies, and illness outcomes in people with cancer, people with depression, and people with co-morbid cancer and anxiety/depression, supporting the importance of the CSM as a theoretical basis from which to explore such representations. Further, multimorbid representations such as combined or competing causal representations, prioritisation of a perceived most challenging illness, beliefs about fear of cancer recurrence, and synergies/antagonisms in the management of illnesses, were found to be associated with self-management strategies and illness outcomes in people with co-morbid cancer and anxiety/depression, with the support needs of these people found to vary based on their history with anxiety/depression. The discovery of these multimorbid illness representations suggests that the CSM may need to be adapted to be more appropriate for people with multiple illnesses. These findings also highlight the need for future research to trial interventions aimed at changing incorrect or maladaptive representations for people with cancer, people with depression, and people with both cancer and anxiety/depression. At the same time, the findings of this thesis highlighted the role of support providers in improving outcomes for people with cancer and anxiety/depression, suggesting a need for increased understanding of illness representations and illness history by providers, improved communication between patients and health professionals, and increased support provision and access to psycho-oncological services for patients.