Assessing the stimulant effects of alcohol in humans.

The stimulant effects of alcohol were assessed in humans. Twenty social drinkers were tested in dyads in the laboratory on three separate occasions, held 7 days apart. For their first session, one-third of the group consumed a dose of alcohol that was calculated to reach a target peak blood alcohol concentration (BAC) of 0.05 g/dl, one-third of the group consumed placebo-alcohol, and one-third consumed diet Sprite. For alcohol and placebo-alcohol conditions, subjects were told that they may or may not be given alcohol. For the soda condition, subjects were told they were consuming soda. Subjective stimulation, activity levels, and speech production were assessed over a 15-min period after beverage consumption (posttreatment) and compared to measurements taken prior to beverage consumption (baseline). Scores on the stimulant subscale of the Biphasic Alcohol Effects Scale (BAES) were significantly greater for the alcohol condition relative to the soda condition. There was also a trend for stimulant scores to be greater for the alcohol condition relative to the placebo-alcohol condition. Activity levels were significantly greater for the alcohol condition compared to either the placebo-alcohol or soda conditions. There were no group differences found for speech production. Subjective stimulant score and activity levels were not correlated. Peak BAC obtained in subjects who consumed alcohol was not correlated with either subjective stimulant scores or activity levels. Activity levels may provide a useful behavioral assay for assessing the stimulant effects of alcohol in humans.