Psychological Resources and Risk Factors in Coronary Heart Disease : Assessment, Impact and the Influence of Mindfulness Training

Sammanfattning: There is strong evidence for the observation that psychological risk factors, such as depressive symptoms, hopelessness, and anxiety are associated with higher risk of developing coronary heart disease (CHD), and also contribute to a worse prognosis among CHD patients. Much less is known about psychological resources, such as Mastery, and their role in cardiovascular medicine. Although the current state of science about the importance of psychological factors has advanced during the last decades, the mental health status of patients is often neglected in clinical practice. The reason behind this gap is multifaceted, including unawareness of the current state of science among professionals and a lack of clear guideline, which in turn, results from a lack of evidence-based ways to address the issues. Furthermore, the measurement of psychological resources is complex and a debated topic in psychology. The aim of this thesis was to investigate: 1) If the use of inverted items in three questionnaires that measure psychological resources and risk factors represent a validity risk in the context of CHD. 2) If psychological resources and risk factors are independently associated with incidence in CHD. 3) If an eight-week course in Mindfulness-Based Stress Reduction (MBSR) is a feasible psychological intervention, as an addition to cardiac rehabilitation. 4) How CHD patients experience the practices of mindfulness and yoga in MBSR.In Study I and II, data from 1007 participants randomly selected from a Swedish community sample, aged 45-69 at baseline (50 % women), were analysed. To study the validity of the self-report instruments Mastery, Self-esteem and Centre for Epidemiological Studies Depression scale (CESD), subscales with only positive and negative items were created. The new subscales were evaluated against three criterion measures; cross-sectional against each other and the circulatory marker of inflammation interleukine-6 (IL-6) (concurrent construct validity); prospectively against 8-year incidence in CHD (predictive validity), and in addition, a factor analysis was used to investigate construct dimensionality. The instruments seemed to be valid measures of psychological resources and risk factors in the context of CHD risk. The new subscales showed the same associations as the original scales, except for the positive items in CES-D. However, this did not have a major influence on the full scale. In Study II a prospective analysis of the impact of psychological factors on 8-year incidence in CHD was performed. The psychological resources Mastery and Self-esteem were negatively associated with CHD, also after adjustment for nine traditional cardiovascular risk factors in Cox proportional hazard models. The protective effect of the two resources, and the increased risk of Hopelessness, remained after adjustment for depressive symptoms. In Study III and IV, a group of CHD patients with depressive symptoms (n=79) was invited to participate in MBSR as a complement to cardiac rehabilitation. Twenty-four patients started MBSR and 16 completed it. The results were compared with a reference group (n=108) of patients from the same clinic, which showed stability in psychological variables over 12 months. MBSR was appreciated by the patients and improvements in psychological risk factors (e.g., depressive symptoms), and an increase in Mastery were observed. Study IV made use of a qualitative content analysis of diary entries written by patients immediately after practice sessions throughout MBSR. Participants described difficulties, both physical and psychological, during the whole course, but as the weeks passed they more frequently described an enhanced ability to concentrate, relax and deal with distractions. From the combined findings in Study III and IV, we conclude that MBSR could be a promising complement to cardiac rehabilitation for a selection of patients.The overall picture, emerging from this thesis, strengthens the argument that psychological factors should be recognized and addressed in clinical practice. It also encourages further studies of how psychological resources could be built, which could inform the development of effective prevention and treatment strategies for CHD patients with psychological distress and also contribute to improved public health interventions.