Quantity of use was indexed as light use (consuming between none and 10 alcoholic drinks during a typical week) and heavier use (consuming more than 10 alcoholic drinks during a typical week). This indicated whether the individual who had initiated had also progressed to heavier use. Progression to three other more serious alcohol use behaviours were also examined: binge drinking (having drunk at least five drinks in a row more than twice in the past year); getting drunk (having been drunk more than twice in the last year) and having been in situations later regretted due to alcohol (once in life-time). These were assessed with the following questions, respectively: (i) ‘Over the past 12 months, on how many days did you drink five or more drinks in a row?; (ii) ‘Over the past the past 12 months, on how many days have you got drunk on alcohol?’; and (iii) ‘Have you ever found yourself in situations you later regretted because of alcohol?’.
