Is Optimism sensitive to the stressors of chronic disease? The impact of type 1 Diabetes Mellitus and Multiple Sclerosis on optimistic beliefs

Abstract

The aim of the present study was to investigate longitudinally the sensitivity of optimistic beliefs (positive outcome expectancies, efficacy expectancies, and optimistic bias) to disease-related stress (measured by disease duration, depressive symptoms, physical symptoms, physical impairment, and life-events) in Type 1 diabetes (n=90) and multiple sclerosis (n=90). First, we examined whether chronically ill patients were less optimistic than a healthy control group (n=60), which showed that patients reported lower levels of optimistic bias but similar levels of the two other optimistic beliefs. Next, we analyzed the stability of the three types of optimistic beliefs across time (one year) for both disease groups, which demonstrated that optimistic bias in MS patients decreased. Finally, the impact of disease-related stressors on optimistic beliefs during a one-year period was determined, showing that all three optimistic beliefs decreased when patients reported depressive symptoms. Together, these findings show that positive outcome expectancies and efficacy expectancies were unaffected by being ill and fairly stable unless patients reported depressive symptoms while optimistic bias appeared to decrease as a result of being ill. Results are discussed in terms of the role of control and depression in optimistic bias.