Recruited subjects met the following criteria: ages 18–29; had previously consumed alcohol but did not meet dependence criteria; had at least one parent with repetitive alcohol-related life problems who met the criteria for alcohol dependence using the Diagnostic and Statistical Manual of the American Psychiatric Association, 4th edition (DSM IV); and were part of a family where at least two siblings met the same criteria (although incomplete recruitment did yield many single sibling families). Recruited siblings were given an alcohol challenge by consuming a 20% v/v solution of 0.75 ml/kg of ethanol (0.6 g/kg for women, and 0.9 g/kg for men) within an 8-minute period. Doses were chosen to produce similar blood alcohol concentrations among individuals. At baseline, 15 min, 30 min, and every half hour after consuming the alcohol, subjects filled out the Subjective High Assessment Scale (SHAS) indicating their feelings of intoxication on 13 items, each rated on a 36-point scale indicating perceived subjective changes from baseline. Subjects were also tested for motor coordination by quantifying body sway over a 1 minute period (BSA-body sway anterior/posterior and BSL-body sway lateral).
