GRM5 and schizophrenia: Bearing in mind the very high prevalence of smoking (more than 60%) in subjects with schizophrenia compared to the general population (de Leon & Diaz, 2005; Sagud et al., 2009), the possible mediating role of mGluR5 as a linkage between schizophrenia and smoking (tobacco misuse or addiction) requires a closer investigation.