Although the finding that heavier drinkers enjoy the effects of alcohol more than lighter drinkers seems intuitive, there has been limited evidence thus far to support this notion. Indeed, the prevailing model, the low-level response theory, posits that persons who experience a lower level of response to alcohol will engage in heavier drinking over time because they do not feel the internal cues of intoxication.88 Our data partially support this theory because HD exhibited reduced subjective sedative and cortisol responses after drinking, compared with the responses of LD, and lack of sedative responses predicted future drinking. However, alcohol markedly increased positive-like effects during ascending to peak BrAC in this group, and these responses also predicted future drinking. In contrast, LD experienced significant increases in sedation during the ascending limb that was sustained for several hours, without concomitant stimulating or rewarding effects. Collectively, these responses may serve as a protective factor underlying these drinkers’ ability to “put the brakes on” and limit their drinking. Taken together, the results indicate that the low-level response theory should be revised to include heightened sensitivity
