Dispositional optimism and the risk of depressive symptoms during 15 years of follow-up: the Zutphen Elderly Study

OBJECTIVE: It is unclear whether the personality trait of dispositional optimism, defined in terms of generalized positive outcome expectancies, life engagement, and a future orientation, has a protective effect on the development of depression in community-dwelling elderly men. METHODS: We included 464 men aged 64 to 84 years (mean 70.8; SD 4.6) with complete data at baseline and at 5 years of follow-up in a prospective cohort study with a follow-up period of 15 years. In 1985, 1990, 1995 and 2000 dispositional optimism was assessed using a 4-item questionnaire, and in 1990, 1995 and 2000 depressive symptoms were assessed by the Zung self-rating depression scale (SDS). Logistic regression was used to estimate odds ratios for the development of depressive symptoms (i.e., Zung SDS > or = 50). RESULTS: The cumulative incidence for depressive symptoms was 44% (n = 202) after 15 years follow-up. Dispositional optimism predicted for a lower cumulative incidence of depressive symptoms with an odds ratio of 0.23 (95% confidence interval 0.15-0.36; high vs. low optimism). The protective effect remained unaffected after multivariate adjustment for age, self-rated health, cardiovascular disease, education, and physical activity. In men free of depressive symptoms in 1990, the protective effect of dispositional optimism persisted. LIMITATION: The dispositional optimism scale has not been validated against the 'Life Orientation Test'. CONCLUSIONS: Dispositional optimism protects against the development of depressive symptoms during 15 years of follow-up in elderly community-dwelling men.