For the current study, three alcohol-related variables were derived including a measure of past 30-day alcohol consumption in grams of ethanol (Consumption), the lifetime maximum number of drinks consumed in a 24-h period (Maxdrinks), and an alcohol problems sum score (Symptoms). Abstainers were not administered the alcohol-related items and therefore were not included in any of the current phenotypic and genetic analyses. Participants were given the option of skipping questions therefore number of participants varies across constructs. When a participant had assessments from different waves, the highest score was used.
