Additionally, alterations in circulating chemokines {e.g., chemokine C–C motif ligand 2 [CCL2, also referred to monocyte chemoattractant protein-1 (MCP-1)], chemokine C–C motif ligand 11 [CCL11, eotaxin-1], chemokine C–X–C motif ligand 8 [CXCL8, interleukin-8 (IL-8)], and chemokine C–X–C motif ligand 12 [CXCL12, stromal cell-derived factor-1 (SDF-1)]} have been recently associated with psychiatric disorders such as cocaine use disorders (6), mood disorders (7, 8), generalized anxiety (9), personality disorders (9), and Alzheimer’s disease (10). This evidence concerns the gene CXCL12 and mood disorder.