When administered intracerebroventricularly, intracerebrally, or intravenously in animal models, exogenous CGRP was found to potentiate fear-related behaviors [48], and it was attested a pivotal role in learning and consolidation of memory in passive avoidance tests [49], in locomotion, nociception, depression-like behaviors [43, 45–47], in anorexia [70], and in addiction [71–73]. This evidence concerns the gene CALCA and major depressive disorder.