Alcohol- and nicotine-related disorders often co-occur (e.g., Hopfer et al., 2001), the presence of either disorder relates to increased severity of the other (Ehringer et al., 2007), both alcohol and nicotine conditions are genetically influenced, and some gene variants might predispose individuals toward both disorders (Froelich et al., 2017; Hettema et al., 1999; Hopfer et al., 2001; Steensland et al., 2007; Swan et al., 1997). Nicotinic receptors might contribute to this overlap (Sherva et al., 2010; Wang et al., 2009) in that the nicotinic receptor partial agonist, varenicline, might also attenuate alcohol consumption (Froelich et al., 2017; Steensland et al., 2007). Oral alcohol challenges and SRE data have highlighted rs1051730 (A/A) and rs8034191(C/C) in the cholinergic gene cluster on chromosome 15q2 as potentially related to lower LR (Joslyn et al., 2008). A rare missense variant of CHRNA5 might relate to more intense oral alcohol challenge responses, including rs749132306, rs2229961, rs55863434, and rs80087508. Data also support possible relationships to alcohol sensitivity for rs2072658 in the CHRNB2 receptor (chromosome 1q21.3) (Ehringer et al., 2007).
