A small number of variants in CNR1 (e.g., rs1049353; rs806368) and CNR2 (rs2501431) have been investigated in the context of emotional processing of socially relevant stimuli [Chakrabarti et al., 2006; Domschke et al., 2008] and in predicting antidepressant treatment response in patients with Major Depression [Domschke et al., 2008; Mitjans et al., 2012, 2013]. This evidence concerns the gene CNR2 and major depressive disorder.