Intoxication or HED frequency was measured using item #3 of the AUDIT questionnaire (“How often do you have six or more drinks on one occasion?”) or similarly worded items, recording the number of typical heavy drinking/intoxication days in categories from “never” to “daily”. As for CON, these categories were recoded into pseudo-continuous number of days per month. In FinnTwin12, the HED item was phrased as “How often do you drink so that you get at least slightly intoxicated?” (ages 14 and 17–18), “How often do you drink so that you get really drunk?” (age 21–26), and AUDIT item #3 (age 34–40). In COGA, the HED item was phrased as “How often did you have five or more drinks in 24 hours during the last 12 months?” and recoded to days per month. In S4S, HED was measured in two ways: 1) a sex-specific question “How often do you have [five/four] or more drinks in a single sitting (considered about a 2 hour period)?” for males/females, or 2) the values from the CON measure, above, if participants’ reported typical drinking quantity
