Since IBD is associated with an increased risk for anxiety and mood disorders (Walker et al., 2008; Graff et al., 2009), we focused in particular on three messenger molecules that are known for their role in the regulation of anxiety and mood: NPY, BDNF, and CRF (Holmes et al., 2003; Martinowich et al., 2007). The gene discussed is NPY; the disease is inflammatory bowel disease.