PREFERENCE FOR ETHANOL AND DIAZEPAM IN LIGHT AND MODERATE SOCIAL DRINKERS - A WITHIN-SUBJECTS STUDY

Preference for ethanol (versus placebo) and diazepam (versus placebo) was assessed in light and moderate social drinkers. The study was desi gned to investigate the relationship of habitual alcohol use to the su bjective and behavioral effects of the two drugs. A secondary purpose of the study was to investigate relationships within subjects in their responses to ethanol and diazepam. Light drinkers (n = 13) who consum ed one to five drinks per week and moderate drinkers (n = 14) who cons umed seven or more drinks per week participated in two seven-session c hoice experiments, one assessing preference for 0.5 g/kg ethanol versu s placebo and the other assessing preference for 20 mg diazepam versus placebo. Drugs were administered double-blind and double-dummy, and t he order of participation in the two experiments was counterbalanced. Sessions were conducted during the evenings in a comfortable laborator y environment. The primary dependent measure was the number of times e ach subject chose the drug (i.e., ethanol or diazepam) over placebo. S ubjective and objective measures of the drugs' effects were obtained u sing standardized self-report questionnaires and psychomotor tests. Wh ereas both groups preferred the ethanol over placebo (i.e., 63% and 83 % ethanol choice for light and moderate drinkers, respectively), only the moderate drinkers preferred the diazepam over placebo (i.e., 40% a nd 73% diazepam choice for light and moderate drinkers, respectively). Subjective responses to the drugs were generally similar across the g roups, although on some measures the light drinkers reported more mark ed drug effects. The number of times each subject chose ethanol was po sitively correlated with the number of times he or she chose diazepam (r = 0.57), and on subjective measures, responses to ethanol and diaze pam were positively correlated. Thus, subjective and behavioral respon ses to diazepam and ethanol were related to habitual alcohol consumpti on, and most notably, moderate drinkers were more likely than light dr inkers to prefer diazepam over a placebo.