Studies have both supported and contested the proposition that lowering pla
sma cholesterol by diet and medications contributes to depression. Evidence
suggests that an imbalance in the ratio of the essential fatty acids (EFAs
), namely the n-6 and n-3 fatty acids, and/or a deficiency in n-3 fatty aci
ds, may be responsible for the heightened depressive symptoms associated wi
th low plasma cholesterol. These relationships may explain the inconsistent
findings in trials of cholesterol-lowering interventions and depression. D
ieting behaviors have similarly been associated with alterations in mood st
ate. This review discusses studies of EFAs and depression and explores the
involvement of dieting-related psychological factors as potential confounde
rs.