Genetic variation of the ghrelin signaling system has previously been associated with paternal alcohol dependence, reported withdrawal symptoms, smoking and type 2 alcohol dependence (i.e. early‐onset and more heredity driven type of alcohol dependence) (Landgren et al. 2010). There is also a report of associations with personality traits such as self‐directedness and self‐transcendence in a sample consisting of controls and type 1 alcohol‐dependent individuals (Landgren et al. 2011a). Interestingly, low self‐directedness characterizes various kinds of addictive behaviors, raising the possibility that the system is involved in normal mental functions, which in turn may render a person susceptible to addictive behaviors.
