This work by Millon et al. [46] indicates that GalR1-GalR2 heterocomplex activated by Gal (1–15) may directly activate the GABA interneurons in the VTA leading to inhibition of the VTA-Limbic-Cortical DA pathway which produces anhedonia-like behavior, a major sign of depression. This evidence concerns the gene GALR1 and depressive symptom measurement.