Previous studies show that alcohol and nicotine dependence share a genetic background (True et al. 1999; Funk, Marinelli & Le 2006; von der Pahlen et al. 2008). This is further supported by the well‐documented co‐use of alcohol and nicotine—also observed in the present study—and the neurobiological interaction between alcohol and nicotine within the mesolimbic dopamine system (for review, see Larsson & Engel 2004; Soderpalm, Lof & Ericson 2009). Given the present results, it is possible that variations in GHSR contribute to the shared genetic background seen for these addictions.
