Recent pre‐clinical and clinical studies suggest that the orexigenic ghrelin signaling system may be of importance for addictive behaviors such as alcohol use disorder and compulsive over‐eating (for review, see Dickson et al. 2011; Leggio et al. 2011). Pre‐clinical studies have shown that ghrelin, just as addictive drugs (Imperato & Di Chiara 1986; Engel et al. 1988; Larsson & Engel 2004; Larsson et al. 2005) and natural rewards (Hernandez & Hoebel 1988; Rada et al. 2000), activates the cholinergic‐dopaminergic reward link in rodents (Jerlhag et al. 2007). Ghrelin has thus been suggested to increase the incentive salience of motivated behaviors such as those associated with drug taking. This hypothesis has been confirmed in several of our pre‐clinical studies in which pharmacological suppression of the growth hormone secretagogue receptor subtype 1a (GHSR‐1a), also known as the ghrelin receptor, was shown to attenuate the rewarding properties of alcohol and nicotine (Jerlhag et al. 2009; Jerlhag & Engel 2011). Further studies involving rodents have shown that ghrelin increases alcohol consumption while a GHSR‐1a antagonist decreases alcohol intake, operant self‐administration of alcohol and prevents
