Does optimism affect symptom report in chronic disease? What are the consequences for self-care behavior and physical functioning?

OBJECTIVE: The aim of the present study was to examine whether optimistic chronically ill patients [50 multiple sclerosis (MS) patients and 65 Type 1 diabetes mellitus (IDDM) patients] overestimate their health status by decreased symptom report, and to what extent such an optimistic interpretation of health status affects self-care behaviour and physical functioning. METHOD: Hierarchical regression analyses were employed to determine the relationship of three concepts of optimistic beliefs (positive outcome expectancies, positive efficacy expectancies and unrealistic optimism) with symptom report, controlling for objective measures of health status; and whether this relationship was mediated by negative affectivity or denial. Hierarchical regression analyses were also employed to assess the impact of optimistic beliefs on self-care behaviour and physical functioning 6 months later. RESULTS: Optimistic beliefs did not affect symptom report with the exception of positive outcome expectancies relating to decreased fatigue report in IDDM patients, a relationship that was mediated by decreased negative affectivity. In addition, positive efficacy expectancies contributed to more self-care behaviours in both MS and IDDM patients. CONCLUSION: Optimistic chronically ill patients do not tend to have a biased perception of their health status, and positive efficacy expectancies appear to encourage self-care behaviour 6 months later. (aut.ref.)