craving. α-synuclein has been shown to play a role in dopamine functioning across several regions of the brain (e.g., inhibiting dopamine synthesis; (Perez et al., 2002)) – making it a candidate for addiction research. In regards to alcohol, Foroud et al. (Foroud et al., 2007), identified haplotypes of SNPs in SNCA that were associated with alcohol craving, but not DSM-IV alcohol dependence diagnosis, supporting our argument here that the study of individual symptoms for AUD may at times point to sources of liability that may be overlooked when studying only the shared variance across AUD symptoms. More recently, our analysis of genes in the dopamine pathway (i.e., DRD1, DRD2, DRD3, DRD4, SLC6A3, as well as SNCA) also suggested common and specific effects from variants in these genes across craving and alcohol dependence (i.e., without craving) (Agrawal et al., 2013). It is important to note that for the current analyses, craving was assessed using a single item (strong desire to use so couldn’t think of anything else). Prior work has contrasted the contributions of varying definitions of craving on AUD diagnosis (Keyes et al., 2011); the NESARC includes two items that effectively separate “strong desire or urge” from “couldn’t think about
