The present findings showing associations between AUDIT scores, smoking and a SNP in GHSR gene are supported by pre‐clinical data showing role for the GHSR‐1a in drug reward. Pre‐clinical studies have shown that pharmacological or genetic suppression of the GHSR‐1a in mice attenuated the ability of alcohol to induce locomotor stimulation, increase accumbal dopamine release and induce a conditioned place preference (Jerlhag et al. 2009). In rodents, GHSR‐1a antagonism reduces alcohol intake and operant self‐administration of alcohol and prevents relapse drinking (Jerlhag et al. 2009; Kaur & Ryabinin 2010; Landgren et al. 2012; Bahi et al. 2013; Suchankova et al. 2013b). Similarly, the rewarding properties of several psychostimulant drugs, including nicotine, cocaine as well as amphetamine, are attenuated by GHSR‐1a antagonists in rodents (Jerlhag et al. 2010; Jerlhag & Engel 2011; Wellman et al. 2011; Wellman, Clifford & Rodriguez 2013), which further supports our hypothesis that ghrelin signaling system regulates reward in general.
