As deficiencies in n-3 PUFAs have been linked separately to depression and to cardiovascular disease, they could act as a higher order variable contributing to the established link between depression and cardiovascular disease.

We therefore examine the relationship between depression and omega-3 polyunsaturated fatty acids (n-3 PUFA), including total n-3 PUFA, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), in patients with acute coronary syndrome (ACS).

Plasma phospholipid levels of n-3 PUFA were measured in 100 patients hospitalized with ACS. Current major depressive episode was assessed by the Composite International Diagnostic Interview (CIDI). Depression severity was assessed by the 18-item Depression in the Medically Ill (DMI-18) measure.

Patients clinically diagnosed with current depression had significantly lower mean total n-3 PUFA and DHA levels. Higher DMI-18 depression severity scores were significantly associated with lower DHA levels, with similar but non-significant trends observed for EPA and total n-3 PUFA levels.

The finding that low DHA levels were associated with depression variables in ACS patients may explain links demonstrated between cardiovascular health and depression, and may have prophylactic and treatment implications.