White matter changes and late-life depressive symptoms: longitudinal study.

Background: Evidence from cross-sectional studies suggests a link between cerebral age-related white matter changes and depressive symptoms in older people, although the temporal association remains unclear.
Aims: To investigate age-related white matter changes on magnetic resonance imaging (MRI) as an independent predictor of depressive symptoms at 1 year after controlling for known confounders.
Method: In a pan-European multicentre study of 639 older adults without significant disability, MRI white matter changes and demographic and clinical variables, including cognitive scores, quality of life, disability and depressive symptoms, were assessed at baseline. Clinical assessments were repeated at 1 year.
Results: Using logistic regression analysis, severity of white matter changes was shown to independently and significantly predict depressive symptoms at 1 year after controlling for baseline depressive symptoms, quality of life and worsening disability (P<0.01).
Conclusions: White matter changes pre-date and are associated with the development of depressive symptoms. This has implications for treatment and prevention of depression in later life.