We have described that the neuropeptide Galanin (1–15) [GAL(1–15)] induces strong depression and anxiogenic-like effects [22,23] and also a strong anhedonia-like phenotype, a key symptom of depression [24], acting through GALR1-GALR2 heteroreceptor complexes in the CNS [23,25]. This evidence concerns the gene GAL and major depressive disorder.