only the COGA studies have examined nAChR genes and adult alcoholism, and only the CHRNA5 gene has been associated with alcohol dependence (Johnson et al., 2006; Wang et al., 2008; Zhu et al., 2005). Here we used FBAT-PC to combine four quantitative measures of alcohol-related behaviors in an attempt to capture a complex phenotype driven by genetics. Interestingly, the item most highly correlated with the composite phenotypes was the quantity variable “average number of drinks when drinking in the past year”. This item differs slightly from the other three in that it measures recent rather than lifetime behavior. Some of the studies mentioned above (Ehringer et al., 2007; Schlaepfer et al., 2008a; Zeiger et al., 2008) have examined a “maximum drinks” measure, which is defined as the “number of drinks a day at a time when drinking the most.” Although this measure had been collected in the NYS sample, it was not included in our original analysis because we felt the “average number of drinks” might be more reflective of overall drinking patterns for an individual. In this sample, the “max drinks” phenotype is modestly correlated with “average drinks” (r2 = 0.25; p < 0.001). In an effort to examine
