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

Background & aims: 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.

Methods: 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.

Results: 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).

Conclusions: 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.