This disclosure relates to an animal model of human disease. More specifically, this disclosure relates to a rodent model of mood disorders such as unipolar depression and an anxiety disorder. Disclosed herein are genetically modified rodent animals that carry a humanized G protein-coupled receptor 156 (GPR156) gene that encodes a mutant human GPR156 protein comprising Asp at an amino acid position corresponding to position 533 in a full length wild type human GPR156 protein.