The DEPOXIN project analyzed various biomarkers in children and adolescents with depression and compared the results with healthy controls as well as an association with severity of depression and mutual associations between parameters like omega-6/omega-3 fatty acid ratio, lipid profile and HDL subfractions, secondary inflammatory markers (homocysteine, thromboxane), brain-derived neurotrophic factor (BDNF), vitamin D, oxidative stress markers, stress hormones, and tryptophan catabolism metabolites. Here, BDNF is linked to depressive symptom measurement.