Abnormal erythrocyte fatty acid composition in first-diagnosed, drug-naïve patients with depression

The correlation between fatty acids (FAs) and depression is not yet conclusive. This study examined the relationship of FAs composition with the presence and clinical characteristics of first-diagnosed, drug-naïve patients with depression. A total of 139 first-diagnosed, drug-naïve patients with depression and 55 healthy controls (HCs) were included in the cross-sectional study. The levels of erythrocyte membrane FAs were compared and then the correlation between clinical symptoms and fatty acid levels in depression was investigated. Compared to HCs, patients with depression had higher C18:1n9t (z = −2.033, p = 0.042), C20:4n6 (z = −2.104, p = 0.035), C20:3n6 (z = −2.104, p = 0.035) and n-6 polyunsaturated fatty acids (PUFAs) (z = −2.127, p = 0.033), whereas the levels of C18:1n9c (z = −3.348, p = 0.001) were significantly lower. Higher C20:3n6, C20:4n6, C18:1n9t and n-6 PUFAs levels were associated with higher severity of depressive and anxiety symptoms in patients with depression, and the correlation remained after adjusting for the related confounding factors (p < 0.05). Patients with first-diagnosed, drug-naïve depression show abnormal erythrocyte fatty acid composition. Trans fatty acids (TFAs) and n-6 PUFAs levels are closely related to clinical characteristics of depression. This study indicated that increased n-6 PUFAs and TFAs are characteristic changes of first-diagnosed, drug-naïve depression.