They could also be influenced by altered extra cranial S100B expression, for example, in patients with comorbid heart disease, obesity, or metabolic syndrome (Mazzini et al., 2005, 2007, 2009; Steiner et al., 2010a, 2010b), which might be a possible explanation for the sometimes contradictory findings on the role of S100B in major depression that are found in the literature. Here, S100B is linked to major depressive disorder.