Participants were asked to report on their drinking in the past month with items regarding how frequently they drank and how many drinks they typically consumed on a drinking day. These items were combined to create a single measure of grams of ethanol consumed in the last month, using a method previously described (Dawson, 2000) and reported for the current sample by Salvatore et al. (2016). Briefly, the frequency and quantity variables were multiplied, and that product was multiplied by 14 (corresponding to the number of grams of ethanol in a standard alcoholic drink). Responses were windsorized with a maximum value of 2,000 g to account for unlikely responses. Values were natural log transformed (after adding 1 to each value). Phenotypic data were available for 7,374 participants.
