Depression and anxiety are prevalent in adults with diabetes and are associated with poorer adherence to diabetes self-care. The Common Sense Self-Regulation Model (CS-SRM) hypothesises that both illness cognitions and emotions determine adherence to health behaviours but little is known about the causal pathways through which poor emotional health impairs adherence. Using the CS-SRM as a theoretical framework this thesis aimed to identify the pathways that exist between diabetes cognitions and poor emotional health and explored their combined and independent effects on diabetes self-care. A systematic review with meta-analysis identified that all previous observational studies used cross-sectional designs to explore the relationships between diabetes cognitions and poor emotional health, excluding one. Randomised controlled trials showed that changes in diabetes cognitions were associated with changes in poor emotional health but these mechanisms of action were not confirmed by mediation analyses. Few observational studies have rigorously tested how diabetes cognitions and poor emotional health operate together to determine diabetes self-management behaviours. This thesis used a longitudinal design to test whether: i) diabetes cognitions and poor emotional health have a longitudinal bi-directional relationship and ii) diabetes cognitions and poor emotional health have a combined (mediated) and independent (direct) longitudinal effect on diabetes self-care. Outpatients with Type 2 diabetes (N=261) were recruited at baseline and completed self-report measures of poor emotional health (Well-being Questionnaire), cognitions (Revised Illness Perception Questionnaire; Beliefs about Medicines Questionnaire) and diabetes self-care (Summary of Diabetes Self-Care Activities Scale) at baseline and six months follow-up. Hypothesised pathways were tested simultaneously using structural equation modelling. Participants who were more anxious at baseline perceived diabetes to be unpredictable and were apprehensive about their medications at follow-up. These effects were not observed for depression. Baseline diabetes cognitions did not predict change in poor emotional health at follow-up. Equally, neither baseline depression or anxiety predicted change in diabetes self-care behaviours at six months (directly or indirectly via diabetes cognitions). Baseline personal control beliefs remained independent of poor emotional health: greater personal control beliefs were associated with reduced adherence to diabetes self-care. A bi-directional relationship between diabetes cognitions and poor emotional health was absent in this sample. The main direction of effect was from anxiety only to diabetes cognitions. Depression and anxiety had no relationship with diabetes self-care. Whilst personal control remained independent of poor emotional health, mastery beliefs appear to be insufficient on their own to sustain adherence behaviours over time suggesting that interventions should also provide patients with action plans whilst managing outcome expectations. The unexpected findings for the relationship between poor emotional health, cognitions, and diabetes self-care may be because the sample did not include individuals with more severe depression or anxiety. This study needs to be replicated among people experiencing clinically significant levels of depression and anxiety in diabetes.

Type 2 diabetes mellitus affects patients' health across the globe and is costly to manage. The chronic high blood sugar of diabetes is linked to cardiovascular and kidney damage, impaired functional status, and multiple organ failure. To lessen the complications associated with diabetes and promote self-care in those with the disease, health care professionals must be vigilant in offering diabetes education to patients with each clinic or primary care visit. Lack of diabetic educators in the clinic that provided the setting for this study indicated a need to increase clinical staff competency in teaching self-care and diabetes management to patients. The resulting project, guided by Bandura's theory of social learning, involved the creation of an educational curriculum, which was evaluated by 5 content experts with 5 or more years of experience caring for adult patients with Type 2 diabetes mellitus who provided narrative feedback. The content experts indicated satisfaction with the program and offered the following recommendations: (a) implementation of staff coaching on motivational interviewing, (b) additional help in securing medications and blood glucose testing supplies for noninsured patients, (c) translation of patient tools into Spanish at a Grade 3 or 4 reading level for better patient understanding, and (d) proceeding with full implementation after the recommendations are carried out. Improved self-care among diabetes patients could promote positive social change through the prevention of acute, long-term complications and disability.

Caregivers play an integral role in the cancer care system in Canada as they provide unpaid care and support for millions of adults living with and beyond cancer. Although caregiving can be a positive experience for some, assuming a caregiving role can be detrimental to caregivers’ own physical and mental health. Research over the past decade has highlighted the negative impacts of caregiving and called for more efforts focused on improving caregivers’ wellbeing. Most interventions targeting caregivers are largely designed to support them in providing care, with little emphasis placed on specifically promoting self-care behaviours. To address this gap, we designed a brief 4-week self-determination theory-based intervention to improve two self-care behaviours (i.e., physical activity and fruit and vegetable consumption) among cancer caregivers. The primary objective of the mixed-methods research presented in this thesis was to assess the feasibility and acceptability of the intervention. Exploratory objectives included understanding participants’ experiences within the intervention. The single-arm intervention was delivered via four weekly video calls to 13 caregivers (mean age=57.6 [15.4 years]) across Canada. The enrollment rate was 62% and the retention, adherence, and fidelity rates ranged from 90 to 99%. The intervention was generally deemed acceptable by participants; however, modifications such as adding psychological support were suggested. Participants’ experiences participating in the intervention were captured within three themes: (1) (Re)prioritizing self-care behaviours; (2) Finding support for self-care behaviours within the caregiving context; and, (3) Becoming a better caregiver through self-care behaviours. Although promising, modifications to the intervention methods are needed to improve enrolment and better meet caregivers’ needs. This study highlights the importance of self-care behaviours for caregivers and provides valuable information on how to foster these behaviours among this population.