Discriminative-stimulus effects of triazolam in light and moderate drinkers

Background: The results of previous laboratory experiments with humans suggest that light and moderate drinkers respond differentially to the effects of benzodiazepines. The aim of this study was to further assess the behavioral effects of a benzodiazepine in light and moderate drinkers. Methods: To accomplish this aim, 12 volunteers (6 light drinkers and 6 moderate drinkers) learned to discriminate 0.375 mg of triazolam, a triazolobenzodiazepine hypnotic. After they learned this discrimination, a test-of-novel-doses phase was conducted in which a range of doses of triazolam (0, 0.06, 0.125, 0.25, and 0.375 mg) was tested in both groups of volunteers. The subject-rated and performance-impairing effects of triazolam were assessed concurrently. Results: There was not a significant difference between the groups in terms of the number of trials needed to learn the discrimination, nor did the proportion of light and moderate drinkers who learned to accurately discriminate 0.375 mg of triazolam differ significantly. The discriminative-stimulus, subject-rated, and performance-impairing effects of triazolam were an orderly function of dose but did not differ across the light and moderate drinkers. Conclusions: Future studies should examine the discriminative-stimulus effects of a lower dose of triazolam (e.g., 0.25 mg) in light and moderate drinks or use a fading procedure to determine differences in terms of the lowest discriminable dose.