The Upper Bavarian longitudinal community study 1975-2004. 2. Long-term course and outcome of depression. A controlled study.

Objective: The study describes course and outcome over 25 years in depressed and non-depressed men and women from a large community study. Outcome measures covered psychopathology, disability, and impaired functioning.

Method: A depressive syndrome (depressed mood and three additional depressive symptoms) was defined and compared to a control condition without depressive symptoms in the seven days preceding baseline assessment. Assessments focused on three time points: baseline survey, 5-year follow-up, and 25-year follow-up. Self-rating scales as well as expert-rating interviews yielded data on a wide range of social and psychopathological risk factors and outcome measures.

Results: Among participants of all three waves (N=838), the baseline prevalence for depressive syndrome was 18.1%. Depressive symptoms manifest at the first wave had substantial impact over the 25-year study. Subjects with a depressive syndrome were predisposed for later adverse mental health outcomes, more disability in social domains and reduced functionality. No long-term increase or decrease of the prevalence of the depressive syndrome was observed.

Conclusion: There is a persistent and long lasting impact of depressive syndrome, irrespective of diagnostic status, in the general population. Our results underscore the importance of sub-syndromal depressive syndrome when estimating the risk of future mental disorders and functional impairment in the long-term.