The association of vitamin B(12) and folate with depressive disorders may have different underlying mechanisms. Vitamin B(12) may be causally related to depression, whereas the relation with folate is due to physical comorbidity.

Interleukin-6 levels were strongly increased in some subjects with depressive disorders, possibly indicating a specific immunologic process. However, the associations of acute phase proteins with depression in this population-based study could be explained by confounding.

In community-dwelling persons, fatty acid composition is related to depression. Because this relation was not secondary to inflammation, atherosclerosis, or possible confounders, it suggests a direct effect of fatty acid composition on mood.

The incidence rate of depression in the elderly population is low except when episodes of clinically relevant depressive symptoms are accounted for. Most late-life depression occurs in persons with a history of depression. Moreover, the recurrence rate of depressive syndromes does not differ between men and women.

No abstract