CNR1 and obesity due to melanocortin 4 receptor deficiency: For example, intron 2 of the human CNR1 gene contains a 3‐kb linkage disequilibrium block (LD block) that contains 17 polymorphisms, two of which rs2023239 and rs9450898, are associated with addictive behaviors (Ketcherside, Noble, McIntyre, & Filbey, 2017), depression (Icick et al., 2015), psychosis (Suárez‐Pinilla et al., 2015), reduced hippocampal volume in cannabis abuse (Schacht, Hutchison, & Filbey, 2012), nicotine addiction (Chen et al., 2008), obesity (Benzinou et al., 2008), and alcohol abuse (Hutchison et al., 2008; Pava et al., 2012).