Over the following decade, the 453 male probands were invited for an alcohol challenge, with almost all protocols over those 10 years including at least 2 sessions given in random order. One was an active challenge with 0.75 ml of ethanol per kilogram consumed over 10 min as a 20% by volume solution mixed with a noncaffeinated carbonated beverage, and the other was an evaluation with a placebo beverage. In both sessions, the participants’ intensities of reaction to the beverage were monitored at 15 min and every 30 min over a 3-hour period. While over the years the protocol used a range of measures, the items of primary interest included alcohol-related changes in subjective feelings of intoxication, standing steadiness (body sway), and changes in blood cortisol levels. The alcohol-related changes in these measures at 60 minutes (the usual time of peak BACs) as converted to standard deviations from the mean formed the basis of the alcohol challenge LR scores used in the current analyses (Schuckit & Gold, 1988; Schuckit & Rayses, 1979; Schuckit et al., 1987, 1988).
