Life-time use of alcohol and the quantity of alcohol drunk was assessed with the question: ‘Think of all the alcoholic drinks you had during the past 12 months. How many drinks did you have during a typical week? (A “drink” is a glass of wine, a can or half pint of beer or lager, a bottle (e.g. Bacardi breezer) or a single measure of spirits).’ Cigarette use was assessed with the question: ‘During the past month, on average, how many cigarettes did you smoke each day?’. Life-time marijuana use was assessed using the question: ‘During your life, how many times have you used marijuana?’. Possible responses to these questions ranged on a seven-point scale, from never having used the substance to using it more than 30 times.
