The CHRM2 gene shows particular promise because both association and linkage analyses point to a significant relationship between the muscarinic 2 receptor (CHRM2) gene and alcohol dependence even in the presence of comorbid conditions such as depression and drug dependence (Wang et al., 2004; Dick et al., 2007). Several SNPs within the CHRM2 gene have been studied to determine their possible association with event-related oscillations (Jones et al., 2006; Jones et al., 2004). These findings support the role of muscarinic receptors in EEG oscillations and P300 generation. Although there are undoubtedly many genes that affect neurochemical processes that may, in turn, influence the generation of P300 (Frodl-Bauch et al., 1999), the CHRM2 gene appears to be an important candidate gene for better understanding developmental changes in P300 amplitude changes.
