GDNF and type 2 diabetes mellitus: For anhedonia, two biomarkers (eotaxin, MMP-10) had positive and three biomarkers (NT-3, TNFβ, TWEAK) had inverse associations in people with T1D, whereas in people with T2D positive associations were found for ten biomarkers (CD5, CD8A, CXCL6, GDNF, IL-10RB, IL-18R1, IL-8, LIF-R, MIP1α, SIRT2).