Psychosocial and vascular risk factors of depression in later life

Background: Research on the aetiology of late-life depression has typically focused on either risk factors from the psychosocial stress-vulnerability domain or degenerative biological changes (for instance, vascular disease). We examined whether vascular risk factors could be interpreted within the stress-vulnerability model of depression. Methods: The data came from a case-control design, nested in a community survey of elderly people. We compared 83 persons with a recently started episode of major or minor depression with 83 controls, with respect to the occurrence of stressful life events, long-term difficulties, neuroticism, and vascular risk factors (hypertension, heart disease, stroke). Results: The (non-significant) association of vascular risk factors and onset of depressive episodes was not modified by neuroticism or the presence of long-term difficulties. Quite unexpectedly, vascular risk factors seemed to neutralize the depressogenic effect of stressful life events. The effect of vascular risk was significantly stronger in depressive episodes not preceded by a life event than in onsets following an event. Conclusions: Vascular risk factors cannot be interpreted within the stress-vulnerability model, but represent another pathway to depression. Why vascular risk factors reduce the depressogenic effect of stressful life events is not clear. Replication is critical to exclude the possibility of a chance finding.